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L White

Publications and source records attributed to L White.

At least 19 recordsLinked to original sources
PubMed1992

The rhombotin gene family encode related LIM-domain proteins whose differing expression suggests multiple roles in mouse development.

The rhombotin (RBTN1 or Ttg-1) gene was first identified at a chromosome translocation in a T-cell acute leukaemia and later used to isolate two related genes (RBTN2 or Ttg-2 and RBTN3). Complete characterization of these genes in man and mouse shows that all three encode cysteine-rich proteins with typical LIM domains. RBTN1 and RBTN3-derived proteins have 98% identity in the LIM domains but are located on separate chromosomes in man and in mouse while RBTN1 and RBTN2, both located on human chromosome 11p but are on separate chromosomes in mouse, are only 48% identical in this part of the protein. The exon organization of RBTN1 and RBTN3 genes are similar, both having an intron, absent from the RBTN2 gene, in the LIM2-encoding region. The remarkable similarity between rbtn-1 and rbtn-3 proteins is parallelled in their expression patterns in mouse development, since both genes show high expression in restricted areas of the brain, but little lymphoid expression. rbtn-2 expression, however, is more ubiquitous. This gene shows a low level of thymus expression but high expression in fetal liver, adult spleen and B-cell lines, consistent with a role in B-cell development. These results suggest multiple cellular targets for the action of these proteins during development.

Adult↗
PubMed1992

Assessment of dementia in elderly schizophrenics with structured rating scales.

Although a number of elderly institutionalized schizophrenic patients appear to suffer from dementia, little is known about the characteristics of the cognitive impairment or its prevalence in this population. In order to answer these questions it is necessary to first reliably and validly assess dementia in elderly schizophrenic patients. This paper reports the results of a study examining the reliability of assessments of the severity of dementia in schizophrenia using scales designed for other dementing conditions and examining the convergence of ratings of the severity of dementia generated from all available sources of information (patient, caregiver, and chart) versus the chart alone. It was found that the interrater reliability of these ratings was very high. On the other hand ratings generated from the hospital chart alone, without contact with either the patient or caregiver, manifested a systematic bias toward overestimation of the severity of dementia. These results suggest that dementia assessment in schizophrenia does not require different instrumentation from that used in other conditions but that relying on the medical chart alone would induce a systematic bias in the results.

Activities of Daily Living↗
PubMed1992

Non-Hodgkin's lymphomas in children. I. Patterns of disease and classification.

Non-Hodgkin's lymphomas (NHL) are part of an overlapping spectrum of lympho-proliferative diseases in childhood. In the first of this 2 part series, the clinicopathological aspects of NHL in childhood are discussed. The rapid progression of disease, the high incidence of micrometastases (over 80%) at diagnosis, and the propensity of hematogenous spread to the bone marrow and the central nervous system (CNS) as well as the clinico-pathologic 'clusters' associated with particular presenting sites distinguish the pediatric forms of disease. Abdominal primary sites most frequently manifest diffuse undifferentiated (Burkitt's or non-Burkitt's) histopathology, B-cell immunophenotype, FAB-L3 cytomorphology and specific karyotypic and/or genotypic alterations of the immuno-globulin genes and the c-myc oncogene. Mediastinal presentation is associated with lymphoblastic histopathology, T-cell immunophenotype and a variety of less consistent karyotypic and genotypic aberrations. Ki-1 lymphoma, a rare subtype of large cell NHL with specific features is often of T cell origin. The requirements for diagnosis, staging and monitoring are presented in the context of the associations between clinico-pathological presentation and subsequent behavior. The most frequent sites of disease progression and relapse are involvement of the bone marrow and the CNS. For Burkitt's lymphoma there is a historic perspective and a description of particular epidemiologic, clinical, virologic, immunophenotypic and genotypic features. Cytogenetic and molecular biologic studies of genomic rearrangements are advancing the understanding of oncogenesis, clonality, lineage, and clinical behavior. The capacity to detect and amplify DNA from submicroscopic disease may contribute to prognostic stratification both at diagnosis and during subsequent monitoring.

Abdominal Neoplasms↗
PubMed1992

Non-Hodgkin's lymphomas in children. II. Treatment.

The prognosis of non-Hodgkin's lymphoma (NHL) in childhood has improved steadily in the last 2 decades. This is primarily the result of increasingly effective chemotherapy regimens tailored to defined and relatively homogeneous prognostic categories and tested in prospective clinical trials. Surgical excision remains of prognostic benefit only when near-total resection can be performed without delay of chemotherapy. The role of radiation therapy is now limited to the treatment of overt central nervous system (CNS) lymphoma, disease unresponsive to chemotherapy, and certain emergencies. Effective 'prophylactic' treatment of the CNS has been achieved in most series by intrathecal and systemic chemotherapy alone. The most relevant modality of treatment is chemotherapy and a very large number of protocols have been published. The origins of current multi-agent regimens stem both from early experience with cyclophosphamide in endemic Burkitt's lymphoma and from therapeutic studies of acute lymphoblastic leukaemia. Sub-stratification of non-localized NHL has produced protocols designed for either lymphoblastic (mostly T cell) or non-lymphoblastic (mostly B cell) categories. While the cure rate for lymphoblastic lymphoma now exceed 70%, the non-localized non-lymphoblastic disease remains a major obstacle to cure. These patients frequently present with large abdominal primaries and are prone to regional as well as hematogenous dissemination. In particular, involvement of the CNS is now considered to be the most adverse prognostic variable in this group. Recently, highly intensive regimens are addressing these obstacles. On the other hand, NHL defined as localized has been shown to be curable in up to 95% of children with the use of simple chemotherapy regimens as short as 6 months in duration. Salvage of patients who relapse during or after chemotherapy remains bleak but cures are possible with regimens incorporating bone marrow transplantation from either an autologous or allogeneic source. Experimental methods, including biologic and immune response modifiers may also offer future promise.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Nonspecificity of colon-specific antigen in adenocarcinomas. An immunohistochemical study of 422 cases.

To determine the specificity of colon-specific antigen in adenocarcinomas, routinely prepared paraffin-embedded tissue from 422 cases of adenocarcinoma were studied using a commercially available monoclonal antibody to colon-specific antigen and a standard avidin-biotin immunohistochemical technique. Positive reactivity for colon-specific antigen was very common (80% to 100%) in adenocarcinomas of the colon, distal esophagus/stomach, ovary, endocervix, endometrium, lung, pancreas, prostate, and bile ducts. Positive reactions were infrequent in adenocarcinomas of the breast (16%) and in hepatocellular carcinomas (23%). No immunoreactivity was seen in adenocarcinomas of the thyroid or in renal cell carcinomas. It is concluded that colon-specific antigen is not a colon-specific marker in adenocarcinomas. However, it may be useful in ruling out adenocarcinomas of renal or thyroid origin in certain clinical settings.

Adenocarcinoma↗
PubMed1992

Association of N-myc amplification with neuroblastoma: the Australian and New Zealand experience.

Tumour samples from 38 patients with neuroblastoma were analysed for the presence of N-myc amplification. N-myc gene copy number in tumour DNA was determined by Southern blotting, and by dilution analysis where appropriate. Available clinical data, obtained at tissue collection and by subsequent questionnaire included patient age at diagnosis, catecholamine, ferritin and neuron-specific enolase levels, treatment and disease status. This study was designed to investigate the use of N-myc amplification data as an additional indicator for determination of prognosis. Patients with amplified N-myc had more rapid disease progression than those without amplification (P less than 0.005). Stratification of Stage III and IV patients using N-myc amplification permitted identification of a subgroup with poorer prognosis. The results demonstrate that determination of N-myc amplification is important in assessment of prognosis and subsequent treatment in patients with neuroblastoma.

Abdominal Neoplasms↗
PubMed1992

Searches for matched and closely matched related and unrelated bone marrow donors undertaken in a single paediatric unit.

Information regarding the likelihood of finding suitable marrow donors is limited. In order to determine this potential, all patients who received their primary care at a single paediatric institution over a 9 year period and in whom tissue typing studies were initiated are reviewed. Forty-five (31.3%) of 144 patients had a sibling who was human leucocyte antigen (HLA) identical. A further 16 (11.2%) patients had immediate or more distant relatives who were either HLA identical (2.7%) or matched for five of six HLA antigens (8.3%). The possibility that a parent was closely matched with the patient was suggestive from the typing of siblings alone in only half the cases. Unrelated HLA matched donors were identified in four (27%) of 17 bone marrow bank searches. Overall, a potential related donor was identified within the family for 42% of patients and this figure rose to 45% when successful marrow bank searches were included. It can be concluded that initial typing should include both the parents and siblings. If a suitable donor is not found then an extended family and/or bone marrow bank search will identify additional suitable donors in a significant number of families.

Bone Marrow Transplantation↗
PubMed1992

Fungal Pseudoallescheria boydii lung infiltrates unresponsive to amphotericin B in leukaemic patients.

The management of patients with acute leukaemia is often complicated by serious fungal infections, especially of the lungs. The outcome of therapy has historically depended on the early use, efficacy and toxicity of amphotericin B. Pseudoallescheria boydii is an uncommon cause of such infections but as it is more often resistant to amphotericin B early identification may enable the prompt use of alternative and newer antifungal agents. Here we report our experience and review the literature in three cases of P. boydii infection in patients with leukemia, showing unique features such as childhood and central nervous system disease, positive blood cultures and response to itraconazole.

Adolescent↗
PubMed1992

A circadian clock of Drosophila: effects of deuterium oxide and mutations at the period locus.

Mutations at the period (per) locus (1:1.3; 3B1-2) in Drosophila melanogaster lengthen (perL), shorten (pers), or abolish (per0) overt circadian rhythmicity. Deuterium oxide lengthens the free-running circadian period. We tested the effects of deuterium on three mutants of the per gene (pers, perL, and per0) and wild-type Drosophila melanogaster (per+) to assess interactions. With increasing concentrations of deuterium, the free-running circadian period of locomotor activity rhythms increased. The dose-response was linear in all genotypes tested. With increasing dosages of deuterium, circadian rhythms became weaker as evidenced by the signal-to-noise ratio (SNR). Genotype and deuterium changed circadian period length independently and additively, showing no interaction. SNRs for all genotypes converged on a low level as deuterium concentration increased. Deuterium increased life span, except at high concentrations (40 and 50%).

Analysis of Variance↗
PubMed1991

Reduced drug accumulation as the mechanism of extreme clinical resistance to methotrexate in the human T-cell leukemia xenograft, LALW-2.

The mechanisms were examined that underlie the extreme resistance to methotrexate (MTX) by near diploid leukemic T-cells (LALW-2) exposed to the drug only during the course of therapy administered to the patient of origin. Despite the LALW-2 cells being highly resistant to MTX (inhibitory dose for 50% of cells, more than 10(-3) mol/l), southern blot analysis did not show any amplification of the dihydrofolate reductase gene, nor was there any evidence, by comparison with drug-sensitive CCRF-CEM cells, that the gene was overexpressed. Kinetic analysis of dihydrofolate reductase activity in the presence of MTX provided no basis for attributing resistance in LALW-2 cells to a change in enzyme structure. By contrast, studies of MTX accumulation revealed that the LALW-2 cells accumulated significantly less drug than either CCRF-CEM cells or a MTX-resistant CCRF-CEM subline with a characterized transport defect. These data suggest that extreme MTX resistance in LALW-2 cells is mediated by reduced drug accumulation in the absence of any effect on the target enzyme.

Animals↗
PubMed1991

Temporal distribution of human rotavirus serotypes 1,2,3, and 4 in Venezuelan children with gastroenteritis during 1979-1989.

The temporal distribution and clinical severity of rotavirus VP7 serotypes 1, 2, 3, and 4 recovered from 427 Venezuelan children with acute gastroenteritis over a period of 11 years were studied. Rotavirus VP7 serotype was established by ELISA serotyping in 298 (69.78%) of the specimens while the serotype of the remaining 129 (30.21%) samples could not be determined. Of the specimens typed, 85 (19.90% of the total) were serotype 1, 43 (10.07%) were serotype 2, 105 (24.59%) were serotype 3, and 65 (15.22%) were serotype 4. Yearly changes in the frequency of individual serotypes were observed. The predominance of a single serotype with minor contribution from others was noted every year. In this study, serotype 1 appears to induce a less severe illness in comparison with serotypes 2, 3, and 4. No apparent association between the proportion of each serotype and the children's age were found.

Antigens, Viral↗
PubMed1991

Acute myelomonocytic leukemia with bone marrow eosinophilia and inv(16)(p13q22),t(1;16)(q32;q22).

A two-year-old girl presenting with de novo acute myelomonocytic leukemia with eosinophilia (French-American-British [FAB] classification, M4Eo) and inv(16)(p13q22), t(1;16)(q32;q22) involving the same chromosome 16 is described. This is the second report of a variant translocation of an inverted chromosome 16 with chromosome 1 at 1q32. However, the segment 1q32----1qter has been exchanged for 16q22----qter and not 16p13----pter, as reported in the previous case. The additional break at 1q32 and the juxtaposition of 1q32----qter onto chromosome 16 could be relevant to the pathogenesis of the disease.

Bone Marrow↗
PubMed1991

Assignment of the YT blood group locus to chromosome 7q.

The antithetical antigens YT1 and YT2 constitute the YT blood group system (International Society of Blood Transfusion system number 11). Despite being serologically well defined, the YT blood group locus (YT) has not secured a chromosomal location. In our report, peak lods of 3.61 at theta = 0.00 for YT:COL1A2 and of 3.31 at theta = 0.00 for YT:D7S13 allow us to assign YT to the long arm of chromosome 7.

Blood Group Antigens↗
PubMed1991

Mutational analysis of the Drosophila miniature-dusky (m-dy) locus: effects on cell size and circadian rhythms.

A mutational analysis has been performed to explore the function of the Drosophila melanogaster miniature-dusky (m-dy) locus. Mutations at this locus affect wing development, fertility and behavior. The genetic characterization of 13 different mutations suggests that m and dy variants are alleles of a single complex gene. All of these mutations alter wing size, apparently by reducing the volume of individual epidermal cells of the developing wing. In m mutants, epidermal cell boundaries persist in the mature wing, whereas they normally degenerate 1-2 hr after eclosion in wild-type or dy flies. This has permitted the direct visualization of cell size differences among several m mutants. Mutations at the m-dy locus also affect behavioral processes. Three out of nine dy alleles (dyn1, dyn3 and dyn4) lengthen the circadian period of the activity and eclosion rhythms by approximately 1.5 hr. In contrast, m mutants have normal circadian periods, but an abnormally large percentage of individuals express aperiodic bouts of activity. These behavior genetic studies also indicate that an existing "rhythm" mutation known as Andante is an allele of the m-dy locus. The differential effects of certain m-dy mutations on wing and behavioral phenotypes suggest that separable domains of function exist within this locus.

Alleles↗