Search PubMed⌕ Search

Biomedical subjects

A Scott

Publications and source records attributed to A Scott.

At least 235 records · Page 13Linked to original sources
PubMed1989

Pediatric AIDS: clinical presentation and diagnosis.

HIV infection/AIDS in infants and children under the age of 13 years expresses itself clinically so differently from the same infection in adults that a separate classification of the symptomatology has been adopted. Recurrent bacterial infections, as well as various opportunistic infections predominate, and while Kaposi's sarcoma is infrequent in pediatric patients, lymphomas occur with high frequency. The diagnosis of HIV infection/AIDS in children is presented.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Ultrastructural observations on the caecum of the rabbit.

The caecal mucosa of the rabbit has been studied using transmission electron microscopy and its fine structure is considered in the light of its known secretory and absorptive capacities. The luminal surface consists of columnar absorptive epithelium while the crypts are lined with glandular epithelium comprising undifferentiated cells, goblet cells containing dark and light mucigenous granules, and intra-epithelial cells. Endocrine cells occur more commonly in the cryptal epithelium and two cell types have been recognised which correspond to EC and L cells respectively. The lamina propria includes lymphocytes, plasma cells, mast cell and smooth muscle cells. There is little ultrastructural variation within mucosal cells along the length of the caecum.

Animals↗
PubMed1988

Neurological development of small-for-gestational age babies during the first year of life.

137 small-for-gestational age (SGA) infants were examined in the neonatal period and at 2, 6 and 12 months. At each age a structured assessment was used for which a score denoting neurological maturation could be given. The SGA infants were significantly retarded compared with average-for-gestational age (AGA) infants from 2 months onwards. Within the SGA group the mean scores for boys, those who were first-born, breast-fed and/or born to mothers who smoked during pregnancy were in each case significantly higher than the rest at 6 and 12 months. Maternal smoking influenced all aspects of development at 12 months; whereas sex and method of infant feeding mainly affected the motor items, and birth order only those that were socially oriented. Positive associations were found between changes in somatic measures and changes in neurological scores from birth through to 6 months. Infants who grew faster also matured faster during this period of time, and vice versa. Positive correlations were found between size and scores at 2 and 6 months, but not at 12 months.

Age Factors↗
PubMed1988

Cutaneous malignant mixed tumor. Report of a case and review of the literature.

We describe an unusual malignant cutaneous neoplasm having a biphasic growth pattern and apparently arising in a mixed tumor. A lymph node metastasis was similar histologically to the primary lesion, exhibiting both carcinomatous differentiation and areas that appeared sarcomatous. Immunohistochemical stains showed selective staining for high molecular weight keratin in carcinomatous areas and for vimentin in areas having a sarcomatous appearance. The literature of cutaneous malignant mixed tumor is reviewed and possible explanations for the unusual morphology and immunohistochemical staining pattern are discussed.

Biopsy↗
PubMed1988

Plasma bupivacaine concentrations during caudal analgesia and ilioinguinal-iliohypogastric nerve block in children.

Plasma bupivacaine concentrations were measured in 27 children aged 3-7 years who received one of two analgesic regimens for herniotomy or orchidopexy. Analgesia was provided either by caudal epidural bupivacaine 0.2% 2 mg/kg (n = 14) or by ilioinguinal-iliohypogastric nerve block with bupivacaine 0.5% 1.25 mg/kg (n = 13). Mean (SD) peak venous bupivacaine concentrations were 0.57 (0.17) microgram/ml and 0.79 (0.38) microgram/ml respectively. Time to peak plasma concentrations were 29.6 (7.9) and 22.3 (10.9) minutes respectively. These concentrations are well below the potentially toxic level of 4.0 micrograms/ml, but suggest that uptake of bupivacaine is more rapid after ilioinguinal-iliohypogastric nerve block than during caudal analgesia.

Anesthesia, Caudal↗
PubMed1988

Head circumference and developmental ability at the age of seven years.

Data on 365 children who had been small (SGA) average (AGA) or large (LGA) for gestational age at birth were analysed at the age of seven years. Significant positive correlations were found between head circumference and developmental scores in the SGA and LGA groups. These were mainly due to associations between relatively small heads and low scores. Familial factors, social class and sex affect both head circumference and developmental ability at this age. Their influences on these two parameters differ in degree; and in the case of sex, in direction. When account was taken of these other factors the contribution of birth-weight group to the variance in head circumference remained high; but its contribution to developmental scores was reduced.

Birth Weight↗
PubMed1988

Dietary components modulate yolk protein gene transcription in Drosophila melanogaster.

The three yolk proteins of Drosophila melanogaster begin to be synthesized at eclosion. Transcription of the genes is regulated by the genes tra, tra-2 and dsx and also by the insect hormones, juvenile hormone and 20-hydroxyecdysone. We show that there is yet another level of control which is dependent upon feeding. Females that are starved from eclosion show a basal level of yolk protein gene transcription, which is rapidly increased when a complete diet is supplied. We show that the effect is not due to incorrect development of the fat body and is unlikely to be solely due to a general effect on protein synthesis. Later in development, cessation of feeding leads to selective inhibition of yolk protein synthesis and hence egg production. The effects of starvation can be partially overcome by 20-hydroxyecdysone, juvenile hormone, casein, amino acid mix or sucrose, but only a complete medium or live yeast brings about total recovery. Using yp1-Adh fusions (fusions of the promoter region of yp1 to the structural gene for Adh), the DNA sequence required for this diet-enhanced transcription has been located within an 890 bp fragment upstream of the yp1 gene. The insect hormones do not operate on this same DNA fragment.

Animals↗
PubMed1988

Detection of type 1 insulinlike growth factor (IGF) receptors in Wilms' tumors.

Insulinlike growth factors (IGFs) are peptide hormones that regulate proliferation and differentiation of several types of normal and neoplastic cells. Recent studies of Wilms' tumor, a childhood kidney neoplasm, have detected increased expression of IGF-2 mRNA and protein. The present report describes detection of Type 1 IGF receptors in specimens of Wilms' tumor and adjacent nonneoplastic kidney tissue. These receptors recognize both IGF-1 and IGF-2, and binding of either peptide activates endogenous tyrosine kinase activity of the Type 1 IGF receptor beta subunit. These data indicate that Wilms' tumors contain receptors that recognize and respond to exogenous IGF in vitro, and that autocrine IGF production might contribute to the increased proliferation and abnormal differentiation of these cells in vivo.

Electrophoresis, Polyacrylamide Gel↗
PubMed1988

Endocrine cells in the caecum of the rabbit.

An ultrastructural study of the caecal mucosa of the rabbit revealed four endocrine cell types, distinguishable by their morphological features and by the size and appearance of the secretory granules which they contained. Endocrine cells occurred most frequently in the mid-region of the corpus ceci, with fewer cells in other regions of the caecum. The commonest cell type appeared to belong to the widely distributed enterochromaffin cells of the intestinal mucosa; less common were cells corresponding to the L cells of the colon, and more rare were endocrine cell types which corresponded to the M and (probably) S cells of the gastrointestinal tract. The secretions from these cell types may well be important in the diurnal physiological regimen of the rabbit caecum.

Animals↗
PubMed1988

An unusual presentation of inflammatory bowel disease.

A 32 year-old male presented to his general practitioner for a routine health check. Microscopic haematuria was noted in an otherwise asymptomatic and fit patient. Subsequent investigation was normal apart from abnormal liver function tests for which no cause was found. A cholecystectomy was performed for gallstones which were detected by ultrasound after the patient complained of upper right quadrant pain. Wedge biopsy of the liver at operation was suggestive of cholangitis. A barium enema was performed which revealed ulceration of the transverse colon suggestive of Crohn's disease. The association of cholangitis and inflammatory bowel disease is discussed.

Adult↗
PubMed1987

Identification of a female-sterile mutation affecting yolk protein 2 in Drosophila melanogaster.

The three yolk proteins (YP1, YP2 and YP3) of Drosophila melanogaster are synthesised in the fat body and ovarian follicle cells and selectively accumulated in the developing oocytes to provide a nutrient source for embryogenesis. We have described the phenotype of a temperature-sensitive female-sterile mutant, fs (1) K313, nad characterised its yolk proteins. This mutation affects the secretion of YP2 and is the first mutation affecting YP2 to be described. Using genetic and molecular tests we argue that the female-sterile phenotype results, at least in part, from the abnormal secretion of YP2 perturbing the follicle cell secretory pathway in general and thus causing defects in chorion protein secretion. The gene coding for YP2 in fs (1) K313 has been cloned and sequenced. Two amino acid substitutions have been found which probably cause the abnormal secretion of YP2 and the resulting female-sterile phenotype.

Animals↗
PubMed1987

A longitudinal study of tooth emergence and somatic growth in 697 children from birth to three years.

The study was on three groups of children who had been small (SGA), average (AGA) or large (LGA) for gestational age at birth. A generalized linear model was used to estimate the effects of associated factors on the number of teeth emerged at one, two and three years. When the groups were combined, birth weight, birth order, maternal smoking during pregnancy and the children's height and head circumference at a given age all emerged as significant explanatory variables. The effect of maternal smoking was the reverse of that expected and evident only in the AGA and LGA groups. The associations with postnatal size were strongest in the SGA group and mainly low or negative in the LGA group. The birth-order effect was similar in all three groups.

Age Determination by Teeth↗
PubMed1987

Interleukin-1 induces mucus secretion from mouse intestinal explants.

Secretion of goblet cell (GC) mucus occurs during immune reactions in the gut. As human macrophages produce a substance that induces mucus secretion from lung explants, we tested the effect of macrophage-derived factor(s) on mucus secretion from intestinal explants. Fragments of mouse duodenum were incubated with macrophage culture supernatants and purified interleukin-1 (IL-1) preparations, and the amount of mucus released was estimated by an enzyme-linked lectin assay. Both the culture supernatants and the IL-1 preparations induced dose- and time-dependent mucus release. Lipopolysaccharide-induced culture fluids were shown to contain IL-1. Thus, stimulation of mucus secretion from GC can be added to the list of biological activities attributable to IL-1.

Animals↗
PubMed1987

The use of an inhibitor of protein synthesis to investigate the roles of ecdysteroids and sex-determination genes on the expression of the genes encoding the Drosophila yolk proteins.

The three yolk-protein genes of Drosophila are normally expressed only in adult female fat bodies and ovaries. 20-hydroxyecdysone can affect the transcription of these genes in males and females, as can mutations in the sex-determining genes tra, tra-2, ix and dsx. We have asked a number of basic questions about how these genes are regulated, using an inhibitor of protein synthesis (cycloheximide), labelling RNA in vivo, a temperature-sensitive sex-determination mutant (tra-2ts1), and 20-hydroxyecdysone. We have found that the yolk-protein genes are continuously transcribed in the fat bodies of adult females and that maintenance of this transcription requires protein synthesis. Hormone induction in males is also inhibited by cycloheximide, suggesting that the products of other genes are essential both for 20-hydroxyecdysone to be able to switch on the genes, and for their continuous transcription in the female fat body. The products of the tra-2 gene are also required for continuous transcription of the yolk-protein genes, suggesting that the pathway inhibited by the cycloheximide is that of the sex-determination hierarchy. 20-hydroxyecdysone can override the sex-determination system and induce yolk protein synthesis in normal males and tra-2ts reared and maintained at the restrictive temperature.

Animals↗
PubMed1987

Bacterial localization in the caecum of the rabbit.

The indigenous microflora of the rabbit caecum and its associated microenvironments has been examined using transmission electron microscopy. Rods and coccoid forms predominated in the caecal lumen and in association with the lining epithelial cell surfaces. In certain areas a curved flagellate rod-like form occurred in numbers and these exhibited features reminiscent of spirochaetes. The caecal crypts showed a homogeneous population of a monotypic spiral form similar to that found in caecal crypts of certain other mammals. In several cases, fusiform bacteria were found within the apical region of intact epithelial cells. There was no evidence of host reaction and the organisms appeared to be undergoing resting spore formation.

Animals↗
PubMed1986

Growth and proportionality in early childhood. I. Within population variations.

Data on the postnatal growth patterns of 238 small-for-gestational age (SGA) and 241 large-for-gestational age (LGA) babies are presented. Three proportionality ratios were selected; and their changes in shape, by these indices, during the first 7 years are compared with a random sample of 284 children drawn from the same population. Highly significant differences (P less than 0.001) were found between the mean head-chest and head-length ratios for both sexes at birth; but mean chest-length ratios did not differ. Our findings show that these three measures of proportionality differ in their patterns of change over time; in the influence of birthweight group on their absolute values at each age; and the influence of sex within birthweight groups. At 7 years SGA children still had the highest and LGA children the lowest head-chest and head-stature ratios, and the differences were significant (P less than 0.01) for girls. This was mainly due to the relatively small heads of LGA girls. 46% of our sample had a head-chest ratio above unity at the age of 2 years. The "rule of thumb" criterion for the identification of malnourished children, based on the general principle that mean chest circumference overtakes head circumference by the age of 12 months, should not be too strictly applied.

Birth Weight↗