Purchasers' view of localised prostate cancer management.
Explore the source record for details and available documents.
Decision Support Techniques↗
Biomedical subjects
A Walker
Publications and source records attributed to A Walker.
Decline in sperm counts: an artefact of changed reference range of "normal"?
OBJECTIVE: To investigate a reported fall in sperm counts during 1940-90 in relation to the reduced lower reference value of "normal" during the same period by assuming the null hypothesis that no change had occurred in the probability distribution of the sperm concentration. DESIGN: Analysis by using various mathematical models of the probability distribution of sperm concentration together with experimental data which supported a model employing a logarithmic distribution. SUBJECTS: 235 men presenting for stimulated in vitro fertilisation at Midland Fertility Services, Aldridge, in 1992 together with samples of 20 ejaculates from each of five men attending the same centre during 1992-3. RESULTS: The effect of the change in lower reference value for the "normal" sperm concentration (from 60 x 10(9) to 20 x 10(9)/l) depended on the probability distribution of the concentration in the population. If that distribution was normal or uniform, then very little of the reported decline was a consequence of the change in lower reference value. If it was heavily skewed, then most or all of the reported decline may have been a consequence of that change. The limited experimental data available indicate that the distribution was heavily skewed. CONCLUSIONS: Depending on the actual distribution of sperm concentration in the population, the reported decline in concentration may have been accounted for entirely or in part by the change in lower reference value. The original evidence does not support the hypothesis that the sperm count declined significantly between 1940 and 1990.
Humans↗
Africa on the precipice: perspective from South Africa.
Explore the source record for details and available documents.
Health Promotion↗
Specific heparan sulfate saccharides mediate the activity of basic fibroblast growth factor.
In a previous study, we showed that heparitinase releases a 14-saccharide sequence (Oligo-H) from heparan sulfate (HS) with the structure delta GlcUA beta 1,4GlcNSO3-alpha 1,4[IdceA(2S)alpha 1,4GlcNSO3]5 alpha 1,4IdceA alpha 1,4GlcNAc (where IdceA(2S) represents iduronic acid 2-sulfate), which binds to basic fibroblast growth factor (bFGF) with high affinity (Turnbull, J. E., Fernig, D., Ke, Y., Wilkinson, M. C. & Gallagher, J. T. (1992) J. Biol. Chem. 267, 10337-10341). This paper describes further work on the binding properties of HS saccharides and their capacity to mediate bFGF activity in a mitogenesis assay in which responsiveness is dependent on the addition of HS or heparin. Saccharides prepared by heparinase or nitrous acid digestion and heparitinase-resistant fragments five disaccharide units (degree of polymerization (dp) = 10) or less in size were unable to activate bFGF. However, heparitinase-resistant saccharides of dp12-16 were active in the assay; the dp14 and dp16 fractions were equivalent in activity to heparin and more active than the parent HS. Saccharides of the same size and basic structure as the active fractions (> or = dp12) bound to bFGF with high relative affinity. Active saccharides were composed mainly of N-sulfated disaccharides, the predominant unit being IdceA(2S)-GlcNSO3. This was enriched at least 5-fold in the active saccharides by comparison with the original HS. In addition, the dp12 and dp14 active fractions had a notably low content of trisulfated disaccharides (IdceA(2S)-GlcNSO3(6S)) (where GlcNSO3(6S) represents N-sulfated glucosamine 6-sulfate), which are the major repeat units of heparin. The data show that sequences similar in size and basic structure to Oligo-H can mediate the mitogenic activity of bFGF. Overall, the results provide further evidence that specific HS sequences are generated biosynthetically in order to fulfill particular biological functions such as activation of bFGF.
3T3 Cells↗
Postcranial robusticity in Homo. III: Ontogeny.
The influence of developmental factors on long-bone cross-sectional geometry and articular size in modern humans is investigated using two approaches: (1) an analysis of the effects of increased mechanical loading on long-bone structure when applied during different developmental periods, using data collected for a study of upper limb bone bilateral asymmetry in professional tennis players; and (2) an analysis of the relative timing of age changes in femoral dimensions among juveniles from the Pecos Pueblo Amerindian archaeological sample. Results of these analyses are used to interpret the femoral morphology of three pre-Recent Homo juveniles--the H. erectus KNM-WT 15000 and the archaic H. sapiens La Ferrassie 6 and Teshik-Tash 1--as well as observed differences in postcranial morphology between adult Recent and earlier Homo (Ruff et al., 1993). Our findings indicate the following: (1) There are age-related changes in long-bone diaphyseal envelope sensitivity to increased mechanical loading, with the periosteal envelope more responsive prior to mid-adolescence, and the endosteal envelope more responsive thereafter. The periosteal expansion and endosteal contraction of the diaphysis documented earlier for adult pre-Recent Homo relative to Recent humans (Ruff et al., 1993) is thus consistent with a developmental response to increased mechanical loading applied throughout life. The relatively large medullary cavity in the 11-12-year-old KNM-WT 15000 femur is also consistent with this model. However, the two archaic H. sapiens juveniles show relatively small medullary cavities, possibly indicating a modified developmental pattern in this group. (2) Articulations follow a growth pattern similar to that of long-bone length (and stature), while cross-sectional diaphyseal dimensions (cortical area, second moments of area) show a contrasting growth pattern, with slower initial growth from childhood through mid-adolescence, followed by a "catch-up" period that continues through early adulthood. This latter pattern is more similar to the growth curve for body weight, and may in fact partially reflect adaptation of the diaphysis to increased weight bearing. Because of these different growth patterns, articulations appear relatively large, and diaphyseal breadths relatively small during late childhood to mid-adolescence (i.e., about 9-13 years), when compared to adults from the same population. KNM-WT 15000 shows this same proportional difference from adult early Homo specimens, which is therefore interpreted as simply a developmental consequence of his age at death.(ABSTRACT TRUNCATED AT 400 WORDS)
Adolescent↗
Four-million-year-old hominids from East Lake Turkana, Kenya.
A piece of mandible and several isolated teeth are reported from fluviatile sediments older than 4 million years at East Lake Turkana. They most closely resemble hominids from Laetoli, Tanzania and Hadar, Ethiopia which have been assigned to Australopithecus afarensis.
Animals↗
Reanalysis of the Lukeino molar (KNM-LU 335).
This paper details a reanalysis of KNM-LU 335, a hominoid mandibular first molar dated to about 6 Ma from the Lukeino Formation, Kenya. Researchers have argued that this molar closely resembles those of modern chimpanzees and may approximate the ancestral morphotype of humans and chimpanzees. The investigation presented here describes a morphometric study of the Lukeino molar and M1s of Homo sapiens, Pan troglodytes, and early australopithecines. Results indicate that KNM-LU 335 differs from both human and chimpanzee M1s in relative distances (measured in three dimensions) between crown fissure termini. Further, the Lukeino molar shares with early australopithecines a pronounced flaring of the buccal surface of the crown not seen for either modern sample. Results of this study do not exclude KNM-LU 335 as a potential ancestral morphotype for Pan and Homo but provide no evidence that this morphotype resembled modern chimpanzees.
Animals↗
Estrogen action on hepatic synthesis of angiotensinogen and IGF-I: direct and indirect estrogen effects.
In the present study effects of estrogens (natural estradiol and synthetic ethinyl estradiol) on liver derived proteins (angiotensinogen, IGF-I) were investigated in vivo in ovariectomized rats and in vitro in a rat hepatoma cell line (Fe33). The aim of this study was to establish both an animal and an in vitro model for quantification of the hepatic activity of given estrogenic compounds, and to study underlying mechanisms as regards the question of direct or indirect mode of estrogen action. In ovariectomized rats subcutaneous (s.c.)-treatment for 11 days with either estradiol (E2) or ethinyl estradiol (EE) (dose range 0.1-3 micrograms/animal/day) induced a comparable dose-dependent increase in uterine weight indicating a similar estrogenic potency of the two estrogens. Equipotency was also found as regards the effects on IGF-I plasma levels which dose-dependently decreased by about 50% at the highest dose tested (3 micrograms/animal/day). The decrease in IGF-I serum levels was accompanied by a significant 40% decrease in liver IGF-I mRNA. In contrast angiotensinogen plasma levels were affected only by EE (60% increase for the 3 micrograms/animal/day dose) but not by E2. When rats, in addition to ovariectomy, were also hypophysectomized (substituted with human growth hormone and dexamethasone) angiotensinogen again increased by 80% upon administration of 3 micrograms/animal/day EE, whereas IGF-I remained unaffected by EE. In a rat hepatoma cell line (Fe33) which is stably transfected with an estrogen receptor expression plasmid, 10 nmol/l EE for 24 h caused a 2.4-fold increase in angiotensinogen mRNA level. We conclude from our studies that estrogen effects on angiotensinogen serum levels in the rat are direct effects via the hepatic estrogen receptor, whereas estrogen effects on IGF-I serum levels are indirect effects, the primary target of estrogen action being probably the pituitary. The changes in angiotensinogen serum levels in the rat model are comparable to the situation in humans indicating the rat model and the Fe33 model to be useful tools to study the hepatic activity of estrogenic compounds.
Angiotensinogen↗
Kinetics of blood free and milk casein-amino acid labelling in the dairy goat at two stages of lactation.
The kinetics of blood free amino acids (AA) transfer into milk casein were compared in goats (n 4) at 61 (SE 5) d (Expt 1; post-peak, 4.51 (SE 0.26) kg milk/d) and at 180 (SE 6) d (Expt 2; late, 2.36 (SE 0.16) kg milk/d) of lactation during non-primed, continuous (Expt 1, 12 h; Expt 2, 16 h) intravenous infusions of mixtures of L-[1-13C]leucine and L-[1-13C]phenylalanine with either L-[1-13C]valine (Expt 1) or L-[5-13C]methionine (Expt 2). The 13C enrichments of blood free and casein-bound AA were fitted to a single exponential model to estimate isotopic plateaux and the fractional rate constant for milk casein labelling. Milk protein output and its contribution to whole-body flux was higher in Expt 1 (post-peak) than in Expt 2 (late lactation), but the kinetics of 13C labelling of the casein-bound AA were similar for all AA tracers in both experiments. At both stages of lactation the delay (6-8 h) between the attainment of isotopic plateau for the blood free AA and the corresponding attainment of plateau for the casein-bound AA indicated that the blood free pool was not the immediate precursor pool for milk casein biosynthesis. Plateau enrichments of casein-bound AA were generally higher than those for the corresponding blood free AA in both experiments. These results indicate that the relative contributions of different AA sources to the immediate precursor pool for milk casein biosynthesis are similar at different stages of lactation despite major changes in the partitioning of whole-body flux towards milk protein output. Non-milk protein fluxes were also similar in post-peak and late lactation.
Amino Acids↗
Child abuse, sudden infant death syndrome, infectious disease, and vaccinations.
Clinicians all too often face the difficult dilemma of deciding whether a bone fracture in a young child was intentional. A structured expert consensus process suggests that all rib fractures; midshaft or metaphyseal fractures of the humerus; and fractures of the radius, ulna, tibia, or fibula in children younger than 1 year of age are highly likely to have been caused by abuse. Abused children are more likely to have negative social relationships with other children than their school-aged peers. Research on the causes of sudden infant death syndrome is still confounded by the likelihood that some deaths for which the label was misapplied are included in many studies; however, the presence of smokers in the household in the postnatal period appears to be yet another factor associated with increased risk. Congenital syphilis is on the rise. Detection of infants who have been infected is incomplete. Lack of prenatal care is strongly associated with infection. Cord serology is not sensitive enough to detect all possible cases. Testing of both maternal and neonatal sera results in detection of more infants at risk. Current tests still result in the treatment of some infants who are not themselves infected. Amoxicillin clavulante given twice daily rather then thrice, cefixime given once a day, and a single intramuscular dose of ceftriaxone have all shown acceptable--though not exceptional--cure rates for otitis media. Price is a consideration. Fewer courses of antibiotics would be necessary if more infants were breastfed. Exclusively breastfeeding to at least 4 months cuts the number of bouts of otitis media almost in half.(ABSTRACT TRUNCATED AT 250 WORDS)
Bacterial Capsules↗
Gene deletion causing adrenal hypoplasia congenita and hypogonadotrophic hypogonadism.
We report a patient with X-linked adrenal hypoplasia congenita and hypogonadotrophic hypogonadism in whom there were no clinical or biochemical features of either glycerol kinase deficiency or Duchenne muscular dystrophy. (The adrenal hypoplasia congenita and glycerol kinase loci map in Xp21 distal to Duchenne muscular dystrophy, and proximal to DXS727). DNA isolated from our patient was analysed by PCR amplification with primers for appropriate loci in the Xp21 region. This analysis revealed the absence of DXS319, which lies near the adrenal hypoplasia congenita deletion critical region, and the presence of DXS727, which is distal to the gene. The absence of glycerol kinase deficiency biochemically and clinically was consistent with the presence of one glycerol kinase exon product from PCR primers P17/P18 which lies within the glycerol kinase gene. The hypogonadotrophic hypogonadism is universally found in X-linked adrenal hypoplasia congenita and is thought to be pituitary in origin. These findings suggest that a gene locus resulting in hypogonadotrophic hypogonadism is present in the Xp21 region and is an integral part of the adrenal hypoplasia congenita gene or in close relationship to it.
Adolescent↗
Rapid degradation of the triazinone herbicide metamitron by a Rhodococcus sp. isolated from treated soil.
Seven bacterial isolates which degraded the herbicide metamitron (3-methyl-4-amino-6-phenyl-1,2,4-triazin-5-one) were obtained from field-enhanced soil by liquid enrichment culture. All isolates appeared to be identical and a representative, 0246b, was identified as a Rhodococcus sp. by cell wall and fatty acid analyses. This isolate degraded metamitron as the sole source of carbon within 24 h at 25 degrees C and this is the first report of a bacterium capable of growing with metamitron as the sole source of carbon. Metamitron was degraded less rapidly when it was the sole source of both carbon and nitrogen. The rate and extent of degradation was affected by the presence and type of additional sources of carbon and nitrogen in the culture medium. In studies with [14C]-phenyl-labelled metamitron Rhodococcus sp. 0246b partly mineralized the phenyl ring.
Biodegradation, Environmental↗
Technical note: the measurement of mammographic room protection.
Owing to the inherent design of mammographic X-ray tubes, transmission measurements through the surrounding protective barriers are difficult to obtain using the primary beam. An alternative method has been developed which employs an iodine-125 source. Transmission measurements were obtained through common building materials using both the iodine-125 source and a mammographic X-ray beam generated at 35 kVp. Measurements were converted into an aluminium equivalence, from which correction factors were calculated to convert the aluminium equivalence determined using iodine-125 to the true aluminium equivalence. Average correction factors for samples of glass, chipboard and plasterboard were 1.10, 0.75, and 0.85, respectively.
Construction Materials↗
Consultation with the specialist. Anticholinergic medications in pediatric gastrointestinal disease.
Explore the source record for details and available documents.
Child↗
Common health problems in Northern Territory aboriginal children.
Aboriginal children in the Northern Territory suffer health problems similar to children in Third World countries. The major problems are malnutrition, diarrhoeal disease and respiratory tract infections. Infections in all systems are common and low birth weight due in significant part to poor growth in utero is a major problem in the newborn period.
Child↗
Partial skeleton of Proconsul nyanzae from Mfangano Island, Kenya.
A partial skeleton attributed to Proconsul nyanzae (KNM-MW 13142) is described. The fossils were found at a site on Mfangano Island, Kenya, which dates to 17.9 +/- .1 million years ago. KNM-MW 13142 consists of six partial vertebrae (T12-S1), a nearly complete hipbone, most of the right femur and left femoral shaft, a fragmentary tibia and fibula, and a nearly complete talus and calcaneus. This skeleton provides the first pelvic fossil known for any East African Miocene hominoid. The new Proconsul specimen is compared to a large sample of extant anthropoids to determine its functional and phylogenetic affinities. In most aspects of its anatomy, KNM-MW 13142 closely resembles nonhominoid anthropoids. This individual had a long, flexible spine, narrow torso, and habitually pronograde posture, features characteristic of most extant monkeys. Evidence of spinal musculature suggests a generalized condition intermediate between that of cercopithecoids and hylobatids. The hindlimb of KNM-MW 13142 exhibits relatively mobile hip and ankle joints, with structural properties of the femur like those of hominoids. This mix of features implies a pattern of posture and locomotion that is unlike that of any extant primate. Many aspects of the Proconsul nyanzae locomotor skeleton may represent the primitive catarrhine condition.
Animals↗
Squamosal suture of cranium KNM-WT 17000.
Explore the source record for details and available documents.
Animals↗
Postcranial robusticity in Homo. I: Temporal trends and mechanical interpretation.
Temporal trends in postcranial robusticity within the genus Homo are explored by comparing cross-sectional diaphyseal and articular properties of the femur, and to a more limited extent, the humerus, in samples of Recent and earlier Homo. Using both theoretical mechanical models and empirical observations within Recent humans, scaling relationships between structural properties and bone length are developed. The influence of body shape on these relationships is considered. These scaling factors are then used to standardize structural properties for comparisons with pre-Recent Homo (Homo sp. and H. erectus, archaic H. sapiens, and early modern H. sapiens). Results of the comparisons lead to the following conclusions: 1) There has been a consistent, exponentially increasing decline in diaphyseal robusticity within Homo that has continued from the early Pleistocene through living humans. Early modern H. sapiens are closer in shaft robusticity to archaic H. sapiens than they are to Recent humans. The increase in diaphyseal robusticity in earlier Homo is a result of both medullary contraction and periosteal expansion relative to Recent humans. 2) There has been no similar temporal decline in articular robusticity within Homo--relative femoral head size is similar in all groups and time periods. Thus, articular to shaft proportions are different in pre-Recent and Recent Homo. 3) These findings are most consistent with a mechanical explanation (declining mechanical loading of the postcranium), that acted primarily through developmental rather than genetic means. The environmental (behavioral) factors that brought about the decline in postcranial robusticity in Homo are ultimately linked to increases in brain size and cultural-technological advances, although changes in robusticity lag behind changes in cognitive capabilities.
Animals↗