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Biomedical subjects

L Gibson

Publications and source records attributed to L Gibson.

At least 37 records · Page 2Linked to original sources
PubMed1994

FISH diagnosis of partial trisomy 13 and tetrasomy 13 in a patient with severe trigonocephaly (C) phenotype.

An infant girl with manifestations resembling Optiz trigonocephaly (C) syndrome who died at age 6 days was found to have a complex chromosome abnormality with t(13;18)(q22;q23) and a recombinant chromosome 13 involving duplicated segments of 13q. Precise characterization was possible with the application of fluorescence in situ hybridization (FISH) using chromosome specific probes. The patient's phenotype is compared to that of other syndromes involving trigonocephaly.

Abnormalities, Multiple↗
PubMed1994

Healing with humor.

Explore the source record for details and available documents.

Adaptation, Psychological↗
PubMed1994

Quality assurance in the voluntary sector.

Reports on a small-scale quality assurance analysis of rural mental health drop-in centres. Within a cross-sectional research design, measures were taken of the centres' structure, process and outcome. The instruments used to take these measures were structured interviews, questionnaires and direct observation, which were applied to clients, staff and referrers. It was found that the centres achieved their objectives with considerable success, including high levels of client and referrer satisfaction. Concludes that the three centres provided a quality service which complements the formal options (i.e. NHS and Social Services). Draws implications for the extension of NHS staff roles in relation to the voluntary sector.

Adult↗
PubMed1993

Molecular and cytogenetic characterization of 9p- abnormalities.

We report on 2 girls with terminal deletion of the short arm of chromosome 9 with concurrent duplication unrecognizable by routine chromosome studies. The phenotype of the patients was not specifically suggestive of the 9p-syndrome in the absence of trigonocephaly and long philtrum as cardinal manifestations. In addition to psychomotor retardation, their manifestations were mild and include upward slant of palpebral fissures and dolichomesophalangy which are characteristic of del(9p). Chromosome abnormalities were de novo in both cases. The two rearranged chromosomes 9 exhibit similar G-banding patterns and suggested the possible duplication of distal 7p. Fluorescence in situ hybridization (FISH) with a chromosome-7 specific library probe indeed identified that one derivative chromosome 9 was the result of a translocation between chromosomes 7 and 9 [der(9)t(7;9)(p15.3;p24] but failed to detect a signal on the other derivative 9. In the second case, the concurrent abnormality was an inverted duplication of proximal 9p and deletion of distal 9p [inv dup(9)(p13-->p22::p22-->qter)] confirmed by FISH using a chromosome 9 specific library probe. FISH clearly identified the origin of these 2 abnormal chromosomes 9 and provided crucial information for clinical evaluation. We emphasize the importance of utilizing updated cytogenetic and molecular techniques in the precise delineation of subtle or complex abnormalities where there are no useful phenotypic clues.

Abnormalities, Multiple↗
PubMed1993

The estrogen receptor cooperates with the TGF alpha receptor (c-erbB) in regulation of chicken erythroid progenitor self-renewal.

A unique combination of growth promoting factors is described that allows growth of large amounts (10(10)-10(11)) of normal erythroid progenitors from chick bone marrow. These erythroid progenitors express the estrogen receptor (ER) as well as the receptor tyrosine kinase TGF alpha R/c-erbB. They require both TGF alpha and estradiol for sustained self-renewal in vitro, but terminally differentiate upon withdrawal of TGF alpha and inactivation of the ER by an antagonist (ICI 164.384). Overexpression of the human ER in erythroblasts devoid of endogenous ER revealed that the hormone-activated ER alone arrested erythroid differentiation and repressed a large group of erythrocyte genes. When similarly overexpressed, TGF alpha R/c-erbB inhibited the expression of a distinct, but overlapping, set of genes. The endogenous ER and TGF alpha R/c-erbB affect erythrocyte gene expression in a similar, but less pronounced fashion. Surprisingly, suppression of ER function by antagonist efficiently inhibited erythroblast transformation by tyrosine kinase oncogenes, suggesting a role of the endogenous ER in leukemogenesis. We speculate that the oncogenes v-erbB and v-erbA cooperate in erythroleukemia induction by a mechanism that is employed by TGF alpha R/c-erbB and ER to regulate normal progenitor self-renewal in response to external signals.

Animals↗
PubMed1992

The v-erbA oncogene requires cooperation with tyrosine kinases to arrest erythroid differentiation induced by ligand-activated endogenous c-erbA and retinoic acid receptor.

The v-erbA oncogene, a mutated version of the thyroid hormone receptor alpha (c-erbA/TR-alpha), cooperates with tyrosine kinase oncogenes in erythroblast transformation. Here we show that the ligand-activated, endogenous retinoic acid receptor (RAR-alpha), in cooperation with c-erbA/TR-alpha, efficiently reverses the transforming effect of kinase oncogenes, overcoming oncogene-induced self-renewal by triggering terminal differentiation of the transformed cells into healthy erythrocytes. This differentiation induction was accompanied by up-regulation of erythrocyte gene expression. Similarly, RAR-alpha and over-expressed exogenous c-erbA/TR-alpha efficiently abolished the differentiation arrest caused by v-erbA, while the low levels of endogenous TR-alpha had no effect. In contrast, transformation by v-erbA plus a kinase oncogene was not affected at all by ligand-activated endogenous or over-expressed exogenous TR-alpha and RAR-alpha. These results suggest that oncogene cooperation is required to protect leukemic erythroblasts from differentiation induction via endogenous, nuclear hormone receptors. Endogenous c-erbA/TR-alpha and RAR-alpha apparently cooperated in abolishing erythroblast self-renewal and inducing differentiation, since the respective ligands acted in a synergistic fashion, and overexpressed, non-ligand-bound c-erbA/TR-alpha suppressed endogenous RAR-alpha function in differentiation induction. Genetic evidence is presented that this functional cooperation requires the receptor dimerization domain, suggesting that TR-alpha/RAR-alpha heterodimers play a role in regulation of erythroid differentiation.

Blood Proteins↗
PubMed1992

Modulation of normal erythroid differentiation by the endogenous thyroid hormone and retinoic acid receptors: a possible target for v-erbA oncogene action.

The v-erbA oncogene, a mutated version of the thyroid hormone receptor alpha (c-erbA/TR-alpha), inhibits erythroid differentiation and constitutively represses transcription of certain erythrocyte genes, suggesting a normal function of the proto-oncogene c-erbA in erythropoiesis. Here we demonstrate that the endogenous thyroid hormone receptor alpha (c-erbA/TR-alpha) and the closely related retinoic acid receptor alpha (RAR-alpha) play a role in the regulation of normal erythroid differentiation. Retinoic acid (RA) distinctly modulated the erythroid differentiation program of normal erythroid progenitors and erythroblasts reversibly transformed by a conditional tyrosine kinase oncogene. When added pulsewise to immature cells, differentiation was accelerated while more mature cells underwent premature cell death. Thyroid hormone (T3) alone caused similar but weaker effects. Interestingly, T3 strongly enhanced the action of RA, suggesting cooperative action of the two receptors in modulating erythroid differentiation. Expression of the human RAR-alpha in receptor-negative erythroblasts conferred RA-induced regulation of differentiation to the otherwise unresponsive cells, thus showing that the RAR-alpha is essential for the RA effect. Likewise, enhanced expression of exogenous c-erbA/TR-alpha in erythroblasts rendered them susceptible to modulation of differentiation by T3, suggesting a similar function of both receptors.

Bone Marrow Cells↗
PubMed1992

Molecular definition of the smallest region of deletion overlap in the Wolf-Hirschhorn syndrome.

Wolf-Hirschhorn syndrome (WHS), associated with a deletion of chromosome 4p, is characterized by mental and growth retardation and typical facial dysmorphism. A girl with clinical features of WHS was found to carry a subtle deletion of chromosome 4p. Initially suggested by high-resolution chromosome analysis, her deletion was confirmed by fluorescence in situ hybridization (FISH) with cosmid probes, E13 and Y2, of D4S113. To delineate this 4p deletion, we performed a series of FISH and pulsed-field gel electrophoresis analyses by using probes from 4p16.3. A deletion of approximately 2.5 Mb with the breakpoint at approximately 80 kb distal to D4S43 was defined in this patient and appears to be the smallest WHS deletion so far identified. To further refine the WHS critical region, we have studied three unrelated patients with presumptive 4p deletions, two resulting from unbalanced segregations of parental chromosomal translocations and one resulting from an apparently de novo unbalanced translocation. Larger deletions were identified in two patients with WHS. One patient who did not clinically present with WHS had a smaller deletion that thus eliminates the distal 100-300 kb from the telomere as being part of the WHS region. This study has localized the WHS region to approximately 2 Mb between D4S43 and D4S142.

Abnormalities, Multiple↗
PubMed1991

der(3)t(3;5). Another recurring abnormality in myelodysplastic disorder.

Monosomy for chromosome 5 or a portion of the long arm is a common finding in acute nonlymphocytic leukemia (ANLL) and myelodysplastic syndrome (MDS), especially when the disorder is therapy related [1,2]. If only a portion of chromosome 5 is missing, the loss is usually accomplished by interstitial deletion of various bands, most frequently q12-14 to q31-33 [3]. Occasionally monosomy for 5q is the result of a translocation between chromosome 5 and another chromosome, with the loss of the derivative chromosome that contains 5q. A previously described unbalanced translocation involves chromosome 7: [der(5)t(5;7)(q11.2;p11.2)] and appears to be a recurring abnormality in these disorders [4]. We report here one case of therapy related MDS, one case of MDS which may be therapy related, and two cases of MDS with another "variant" 5q - abnormality, namely a derivative chromosome 3 composed of most of the short arm of chromosome 5 and the long arm of chromosome 3: [der(3)t(3;5)(?p11;?p11)].

Aged↗
PubMed1991

Evaluation of a comprehensive assessment battery for stroke patients.

The authors describe their experience of evaluating a battery of tests to assess function in patients with stroke and head injuries. They consisted of the Abbreviated Mental Test Score, Ravens Progressive Coloured Matrices, Hospital Anxiety and Depression Scale (HAD), Motricity Index, Shortened Rivermead Perceptual Assessment Battery (RPAB), Frenchay Aphasia Screening Test (FAST) and Barthel's Activities of Daily Living Index. These were applied to 50 patients, six of whom had had a head injury and 44 a stroke. Over 80% of subjects were able to complete the battery. Reasons for failure amongst the remainder were language problems, poor concentration and short term memory loss. Abnormalities in one aspect of cerebral function often compromised tests designed to assess another aspect of this. For example, upper limb incoordination interfered with RPAB, language difficulties affected the Abbreviated Mental Test, and HAD, and hemianopia compromised both RPAB and FAST tests. The battery can usually be completed within 1h, and could be performed by a wide range of professionals. It is likely to be particularly useful in screening for abnormalities requiring more detailed evaluation by particular professionals, and in monitoring the progress of patients during the course of treatment.

Activities of Daily Living↗
PubMed1991

Prevalence of histoplasmosis in a midsouthern population.

We found a histoplasmin reactivity rate of 69% in a selected population of normal midsouthern adults. This prevalence is similar to that previously reported and has major clinical implications for area residents who are infected with human immunodeficiency virus and are at risk for disseminated disease with Histoplasma capsulatum.

Adult↗
PubMed1989

Anatomic changes in the pelvis after uncomplicated vaginal delivery: a CT study on 14 women.

We analyzed CT scans of the pelvis made within 24 hr of an uncomplicated term vaginal delivery in 14 women to document the anatomic changes that occur in the immediate postpartum period. Scans were interpreted by three radiologists, and the results were compared with those from pelvic CT scans made from normal, age-matched, nonpregnant women. In addition to soft-tissue windows, bone windows also were obtained to assess the pubic symphysis and sacroiliac joints in both the postpartum women and the control subjects. The mean uterine length, transverse width, and anteroposterior diameter in the postpartum women (14 +/- 1.4, 12 +/- 1.5, and 9 +/- 1.6 cm, respectively) were significantly larger than in the nonpregnant women (7 +/- 1.4, 5 +/- 0.8, and 4 +/- 0.9 cm) (p less than .0001). CT scans showed intrauterine blood in nine of the postpartum women (64%), and three (21%) had intrauterine gas. There was widening of the sacroiliac joint in one (7%) of the postpartum women compared with none of the control subjects. Widening of the pubic symphysis was present in six (42%) of the postpartum women and in none of the control subjects. Six (42%) of the postpartum women had gas in the sacroiliac joints, 33% of which occurred bilaterally; gas in the pubic symphysis was seen in four (28%) of the postpartum scans. In one patient, an asymptomatic muscle hematoma was discovered. We conclude that normal changes in the pelvis after uncomplicated term vaginal delivery include enlargement of the uterus, intrauterine blood, widening of the symphysis and sacroiliac joints, and gas in the sacroiliac joints.

Adult↗
PubMed1984

Evaluation of some serum erythropoietin concentration procedures using serum-containing and serum-free in vitro bioassays.

Studies are reported which were designed to further refine a serum-free culture method to assess the erythropoietic response of fetal mouse liver cells. The objective was to employ such a serum-free system with deproteinized serum concentrates as the test materials in a potentially highly specific assay for erythropoietin (Ep). A serum-free culture method is described which permits responses to Ep (125I-deoxyuridine incorporation) closely comparable to those observed in cultures containing optimal concentrations of sera. Mean recoveries of Ep were acceptable in each of three variations of a serum concentration procedure. However, no correlations were evident between Ep titers in whole sera and those in the concentrates (assayed in both serum-free and serum-containing cultures) with deproteinization and/or concentration procedures involving serum acidification and exposure to boiling water temperature.

Biological Assay↗
PubMed1983

Differences in some erythroid regulatory parameters between two inbred mouse strains.

Normal erythropoiesis in inbred CBA/Tr x CBA/Tr mice is shown to be associated with higher rates of red blood cell production and destruction than in age-matched, but significantly larger, C57Bl6/Tr x C57Bl6/Tr mice. As expected from these observations, serum Ep titers were significantly higher in the CBA/Tr mice than in the C57Bl6/Tr mice. These differences, which appear to result from variations in the operating point for erythropoiesis, can explain the different in vitro erythropoietin sensitivities of hematopoietic tissue from these two mouse strains.

Animals↗
PubMed1983

Stomatocytosis in a colony of captive squirrel monkeys (Saimiri sciureus).

Chronic stomatocytosis, which increased in severity as a function of the time that animals were held in captivity, was observed in a small colony of squirrel monkeys. The stomatocytosis was associated with increasing hematocrits possibly due to a change in packing characteristics of the erythrocytes rather than any overt changes in the erythrocyte mass. Reticulocytes remained at control levels throughout development of the stomatocytosis. The most probable cause of this alteration in erythrocyte shape distribution was dietary, but the exact etiology was not determined.

Animals↗