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Biomedical subjects

M Sawyer

Publications and source records attributed to M Sawyer.

At least 19 recordsLinked to original sources
PubMed1992

Development of the D. melanogaster caudal segments involves suppression of the ventral regions of A8, A9 and A10.

Whereas the segmental organization of the thorax and anterior abdomen is morphologically delineated in both the Drosophila larva and adult, segments in the head and caudal regions lack such well-defined boundaries. Consequently, the organization of these regions has been difficult to decipher. In this study, transformations caused by the bithorax-complex homeotic mutants 48, M3, Ultraabdominal-1 (Uab1) and tumorous-head-3 (tuh-3), as well as the patterns of engrailed gene expression have been analyzed to investigate the segmental organization of the caudal segments. A special emphasis was placed on sense organs appearing in abdominal segments 8, 9 and 10 (A8-A10): We find that: (1) transformations in the caudal segments obey parasegmental borders; (2) the sense organs on A8, A9, and A10 are probably homologous to the pits and hairs in anterior A1-A7; (3) except for the larval anal tuft and the anterior side of A8, all structures in larval segments A8, A9 and A10 are dorsal/lateral in origin; and (4) dorsalization of embryonic A8 and A9 cells leaves space ventrally for A10, as it follows the contracting ventral nervous system during the embryological process of germ band contraction.

Abdomen↗
PubMed1992

Diagnosis of human immunodeficiency virus infection by enzyme-linked immunospot assays in a prospectively followed cohort of infants of human immunodeficiency virus-seropositive women.

The enzyme-linked immunospot (ELISPOT), a method for quantifying specific and total antibody-secreting cells, was used for the diagnosis of human immunodeficiency virus (HIV) infection in a prospectively followed cohort of infants born to HIV-infected women. From July 1, 1987, to June 1, 1990, 127 infants with known HIV infection status were studied. Seventeen of 22 HIV-infected infants had specific HIV-specific antibody-secreting cells (ASC). Among the infected infants rates of ASC positivity increased during the first year of life, from 25% in the first 5 days of life to 78% after 6 months. Two of the five ASC-negative infected infants were further characterized as hypo- or dysgammaglobulinemic by an adjunct ELISPOT assay for total immunoglobulin-secreting cells. Excluding hypo- or dysgammaglobulinemic infants from the analysis, the rate of ASC positivity among infected infants was 85% (17 of 20) after the age of 6 months. None of the 95 uninfected infants had a positive ELISPOT assay, including 55 who were tested in the first 3 months of life. Thus in this series the specificity was 100%. ELISPOT methodology can be a useful technique for the diagnosis of HIV infection in infants of HIV-seropositive mothers.

Female↗
PubMed1990

The attitude of parents to the use of computer-assisted interviewing in a child psychiatry service.

Before undergoing interview, parents reported that a computer-assisted interview would lack the friendly and personal approach of one conducted by a clinician but, after completing the interview, parents showed more acceptance of the procedure. Computer-assisted interviewing has the potential to play an important role in the collection of clinically relevant information from both parents and children referred to child psychiatry services.

Attitude to Computers↗
PubMed1989

Peroxidase-labeled primary antibody method for detection of pestivirus contamination in cell cultures.

Contaminating bovine viral diarrhea (BVD) virus in cell cultures and in fetal bovine serum (FBS) is a well recognized problem. This study describes a direct peroxidase (DP) labeled primary antibody method for detection of pestivirus antigens in cell culture that is simple and reliable. Using this method, most bovine and porcine cell cultures, a cat lung, four mosquito and two monkey cell cultures were found contaminated with BVD virus. The rodent and human cell cultures tested were negative by this method for BVD virus.

Animals↗
PubMed1989

Energy expenditure of Gambian women during peak agricultural activity measured by the doubly-labelled water method.

The doubly-labelled water (2H218O) method was used to measure total energy expenditure (TEE) in ten non-pregnant, non-lactating (NPNL), six pregnant (P) and fourteen lactating (L) women in a rural Gambian community. Measurements were made on free-living subjects at a period of peak energetic stress when high agricultural work loads coincided with a hungary season to induce moderately severe negative energy balance. TEE averaged 10.42 (SD 2.08) MJ/d, equivalent to 1.95 (SD 0.38) times resting metabolic rate (RMR). The energy cost of physical activity plus thermogenesis, derived as TEE-RMR, averaged 4.94 (SD 1.96) MJ/d. Expressed per kg body-weight (103 kJ/kg per d) this component of expenditure was 2.5 times greater than comparative values from inactive, affluent women studied previously (39 kJ/kg per d). Estimated energy intake (EI) in a subset of the women (n 13) was only 4.80 (SD 1.58) MJ/d, yielding an apparent deficit of 6.08 MJ/d between EI and TEE. Weight changes suggested that endogenous fat oxidation accounted for only about 0.85 MJ/d, leaving an unexplained difference of over 5 MJ/d. Critical analysis of possible errors suggests that the new doubly-labelled water method has provided the most reliable estimates and that the estimates of EI were substantially in error. This finding has important consequences for other food intake studies.

Adult↗
PubMed1988

Characterization of glial subpopulations in cultures of the ovine central nervous system.

The cellular composition and in vitro development of glial cultures derived from the rat CNS has been well studied. However, less information is available on similar cultures from other species, particularly higher mammals. To study ovine glial development in vitro, cultures from 50-day fetal to adult animals were characterized with various immunocytochemical markers, which are frequently used to define neural cell subsets in rat cultures. As in rats, both A2B5+ and A2B5- astrocytes can be identified in ovine cultures. However, ovine A2B5+ and A2B5- could not be reliably differentiated by their morphology, which was more influenced by whether the cells were in serum-free or serum-containing media than by their A2B5-positive or -negative status. In addition, ovine A2B5+ astrocytes were present in cultures from early fetal brain before the development of identifiable oligodendrocytes, unlike rat type II astrocytes, which develop only after the appearance of oligodendrocytes. An A2B5+ cell, morphologically similar to the rat 02-A cell, can be found in cultures from fetal ovine cerebrum or cerebellum. A2B5+/glial fibrillary acidic protein (GFAP)- cells in cultures from 100- to 115-day ovine cerebellum appeared to differentiate into A2B5+ astrocytes in serum-containing media. However, in serum-free media, although the A2B5+ cells assumed a more "oligodendroglial-like" morphology, they did not express galactocerebroside or myelin basic protein, suggesting that these cells may not be bipotential as is the rat 02-A cell. Oligodendroglial differentiation was not induced by treatment with dibutyryl cyclic AMP or insulin-like growth factor I. Many cells in cultures from a variety of fetal ages did not label with any of the immunocytochemical markers used, suggesting the need for more cell-type-specific markers to identify neural cell subsets in higher mammals.

Animals↗
PubMed1988

Treatment of bacterial meningitis with once daily ceftriaxone therapy.

Ceftriaxone, a cephalosporin with an extended half-life and excellent antibacterial activity was used to treat bacterial meningitis, given as a single daily intravenous dose of 100 mg/kg on day one, followed by 80 mg/kg daily. A total of 22 patients were treated, of whom 14 had Haemophilus influenzae type b, five had Streptococcus pneumoniae and three Neisseria meningitidis isolated from their CSF. The CSF of all patients became sterile within 24-48 h. The CSF ceftriaxone concentrations 24 h after dosing were 10 to 100-fold higher than the MIC of the pathogenic bacteria early in therapy, and five to 50-fold higher at the end of therapy. Side effects encountered included mild diarrhoea (32%), thrombocytosis (77%) and neutropenia (9%), but none caused therapy to be stopped. Ceftriaxone is a safe and effective antibiotic for the treatment of bacterial meningitis when administered once daily.

Adolescent↗
PubMed1987

First report of the Australian Corneal Graft Registry.

In the Australian Corneal Graft Registry's first 18 months of operation, May 1985 to November 1986, data supplied by 53 surgeons relating to 322 graft recipients have been entered and analysed with respect to: the most common presenting diseases (primarily keratoconus, bullous keratopathy and corneal opacities), risk factors (especially prior sensitisation to HLA antigens, corneal vascularisation, past or present anterior segment inflammation and history of raised intraocular pressure [IOP]), donor and recipient sex, cause of donor death, storage procedures for donor eyes, operative procedures accompanying the grafts themselves, and preliminary indications of overall graft survival by actuarial analysis. It is hoped that the establishment of this Registry will not only reinforce the use of actuarial graft survival analysis as the method of choice for transplantation surgeons wishing to monitor the survival of their patients and grafts, but will also provide a useful service for the Australian ophthalmic community in general.

Actuarial Analysis↗
PubMed1987

Experimentally induced ovine border disease: extensive hypomyelination with minimal viral antigen in neonatal spinal cord.

Border disease (BD) was experimentally induced in 9 lambs by inoculation of their dams with the BD-31 strain of border disease virus (BDV) at 50 days of gestation. These ewes developed serum-neutralizing antibody titers to BDV. The diagnosis of BD in their lambs was confirmed by hairy birthcoats, intrauterine growth retardation, tremors, and hypomyelination. Three clinically healthy age-matched control lambs, whose dams had been given an inoculum containing only BDV-free cell culture supernatant, were studied in parallel. There were significant differences in birth weights and in the lengths of the right tibiae and radii between the affected and the control lambs. There was a gradient in severity of clinical neurologic signs among the affected lambs, which directly correlated with the severity of hypomyelination in their spinal cords. However, the difference in severity of the neurologic deficits did not correlate with differences either in the precolostral serum-neutralizing antibody titers to BDV in these lambs or in the number of BDV antigen-containing cells in their spinal cords. Only approximately 0.01% to 0.3% of spinal cord cells, both in gray matter and white matter, were BDV antigen positive in the affected lambs. These results indicate that extensive infection of CNS cells with their subsequent destruction or functional alteration may not be a critical part of the pathogenesis of the hypomyelination in BD.

Animals↗
PubMed1987

Vitamin B12-responsive neonatal megaloblastic anemia and homocystinuria with associated reduced methionine synthase activity.

We present findings on an infant with neonatal megaloblastic anemia, homocystinuria, and neurologic dysfunction that included developmental delay and tonic seizures. There was no methylmalonic aciduria. Cyanocobalamin therapy was accompanied by complete hematologic and neurologic recovery, diminished homocystine excretion, and subsequently normal neurologic development. Cultured fibroblasts and lymphoblasts showed a reduced methionine synthase activity and a growth requirement for methionine. Cobalamin incorporation by the patient's lymphoblasts was normal, but the proportion of cellular methylcobalamin in the patient's lymphoblasts and fibroblasts were markedly reduced and that of adenosylcobalamin normal. The reduced methionine synthase activity was independent of assay reducing (thiol) conditions, but normal levels of activity accompanied culture of the patient's lymphoblasts in medium with markedly increased cobalamin concentration. The characteristics of the reduced methionine synthase of our patient differ significantly from that of the previously described infant with cobalamin E disease and suggest that genetic heterogeneity may characterize this mutation.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1986

High levels of energy expenditure in obese women.

Total free living energy expenditure was compared in lean and obese women by the new doubly labelled water method and partitioned into basal metabolism and thermogenesis plus activity by whole body calorimetry. Average energy expenditure was significantly higher in the obese group (10.22 versus 7.99 MJ/day (2445 versus 1911 kcal/day); p less than 0.001) resulting from an increase in the energy cost of both basal metabolism and physical activity. Self recorded energy intakes were accurate in the lean subjects but underestimated expenditure by 3.5 MJ/day (837 kcal/day) in the obese group. Basal metabolic rate and energy expenditure on thermogenesis plus activity were identical in the two groups when corrected for differences in fat free mass and total body mass. In the obese women in this series there was no evidence that their obesity was caused by a metabolic or behavioural defect resulting in reduced energy expenditure.

Activities of Daily Living↗
PubMed1986

Psychological adjustment of families of children and adolescents treated for leukemia.

This report describes a follow-up study in which the prevalence of emotional and behavioral problems in a group of 42 children and adolescents treated for leukemia is compared with the prevalence of problems in a matched control group selected from the general population. The prevalence of problems among the siblings of the two groups, and the adjustment of the two groups of families, are also examined. The Achenbach Child Behavior Checklist, for completion by parents, and the Achenbach Child Behavior Checklist and Rutter B2 Behavioural Scale, for completion by teachers, are used to identify both social competence and behavioral problems. In addition, the Family Concept Inventory is used to evaluate the adjustment of families. The leukemic children and adolescents were found to have significantly more problems and less social competence, particularly in school-related activities, than either the control group or their own siblings. There was no difference in the prevalence of problems between the two groups of siblings, nor between the two groups of families. It is suggested that careful prospective studies are needed to identify the cause of the problems experienced by the leukemic children and adolescents so that programs may be developed to prevent their emergence.

Adaptation, Psychological↗
PubMed1986

Glucocorticoid-induced vasoconstriction in human skin. An inhibitory role on phospholipase A2 activity.

The ability of topically applied betamethasone valerate to reduce erythema produced by a variety of vasodilators was assessed. The steroid significantly reduced the erythema induced by topical arachidonic acid, intradermal histamine, and compound 48/80. We postulated that the steroid reduced endogenous phospholipase activity either before or after application of the vasodilators, or both. This action may explain the mechanism of glucocorticoid-induced vasoconstriction in the skin and part of the steroids' action in acute inflammatory skin disease.

Administration, Topical↗
PubMed1986

The treatment of soft tissue after spinal injury.

There are a number of modalities available for the treatment of soft tissue that are applicable to spinal injuries. Each has a long history of use; however, there is relatively little scientific data to support the effects often seen in the clinical setting. Only through careful evaluation and specific diagnosis can these methods of treatment be utilized to their fullest potential. The underlying pathology must always be addressed as well as its soft-tissue manifestations. Direct treatment of the mechanical derangement must take precedence when such conditions exist. The total treatment must incorporate patient education in posture and positioning as well as prophylactic measures. In later stages of rehabilitation, a general strengthening program to further prevent reinjury should be embarked upon. It must always be remembered that treatment of soft tissue alone rarely provides long-lasting relief of symptoms.

Athletic Injuries↗
PubMed1985

Unexpectedly low levels of energy expenditure in healthy women.

A new method for measuring total energy expenditure (TEE) with stable isotopically labelled water (2H218O) was used to measure average daily energy expenditure over 14-21 day periods in 12 healthy women following their normal activity patterns. TEE expressed as a multiple of basal metabolic rate (TEE/BMR) averaged only 1 X 38 +/- 0 X 04. This result is at variance with the widely held assumption that minimum maintenance requirements are 1 X 5 times BMR.

Adult↗
PubMed1985

Glucocorticoid-induced vasoconstriction in canine skin.

Vasoconstriction, manifest as a reduction in blood flow necessary to maintain a constant pressure, was observed over 4 h in the arteries supplying isolated abdominal skin flaps of greyhound dogs treated with intravenously administered betamethasone-17-valerate. Norepinephrine concentration-response curves performed initially and after 4 h showed no significant difference between the treated or control animals.

Animals↗