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Biomedical subjects

D Francis

Publications and source records attributed to D Francis.

At least 19 recordsLinked to original sources
PubMed1992

[Determination of estrogen receptor status in breast cancer by immunocytochemical examination of fine-needle aspirates].

Estrogen receptor status was determined by immunocytochemical examination of fine-needle aspirates in 109 cases of primary invasive breast carcinoma. The results were compared with those from biochemical determination performed on tumor cytosols. Positive agreement was found between qualitative determination (positive/negative) by the two methods in 83% of the cases, and after semiquantitative stratification into three groups the results corresponded in 76%. The predictive value of a positive result on fine-needle aspirate was 96%, and 57% of a negative result. It is concluded that immunocytochemical determination of estrogen receptor status of breast carcinomas on fine-needle aspirate with the applied technique cannot replace the current standard biochemical method.

Aged↗
PubMed1992

The evolution of human chromosome 21: evidence from in situ hybridization in marsupials and a monotreme.

We have mapped five human chromosome 21 (HSA 21) markers in marsupials and a monotreme, two major groups of mammals that diverged from eutherians 130-150 and 150-170 million years before present (MYrBP), respectively. We have found that these genes map to two distinct autosomal sites, one containing SOD1/CBR/BCEI and the other containing ETS2/INFAR, in the marsupials Macropus eugenii and Sminthopsis macroura (which belong to orders that diverged 40-80 MYrBP), as well as in the monotreme Ornithorhynchus anatinus (the platypus). Since marsupials and monotremes diverged independently from eutherians, these data suggest that HSA 21 genes were originally located in two separate autosomal blocks. In another Sminthopsis species, SOD1 is linked to TRF (a marker on HSA 3q), suggesting that the ancestral SOD1/CBR/BCEI region also included HSA 3 markers. We suggest that these blocks became fused early in the eutherian evolution to form a HSA 3/21 chromosome, which has remained intact in artiodactyls, but has been independently disrupted in both the primate and rodent lineages.

Animals↗
PubMed1992

High frequency jet ventilation: use of the Bain system for entrainment.

The use of a Bain system to convey anaesthetic gases for entrainment during high frequency jet ventilation (HFJV) was evaluated by examining the effect of varying the fresh gas flow (Vf) on the end-tidal carbon dioxide (PECO2) in 46 ASA physical status I and II patients undergoing extracorporeal shock-wave lithotripsy (ESWL). Anaesthesia was induced with methohexitone (1-2 mg.kg-1), fentanyl (1-1.5 micrograms.kg-1) and vecuronium (0.1 mg.kg-1). After endotracheal intubation with a Mallinckrodt Hi-Lo Jet cuffed endotracheal tube, the patient was immersed in a water bath and HFJV at 150 breaths per minute was instituted with an Acutronic AMS 1000 jet ventilator attached to the side channel of the Hi-Lo tube. A Bain system was attached to the proximal end of the endotracheal tube to provide gases for entrainment. Anaesthesia was maintained with an intravenous infusion of methohexitone (5 mg.kg-1.h-1) and 50% nitrous oxide in oxygen for both the jetted and entrained gases. PECO2 was determined at 5-min intervals by a single-breath technique using a calibrated Engstrom Eliza capnograph. Thirty patients were randomly allocated to receive Vf's of 50 (Group 1), 75 (Group 2) and 100 (Group 3) ml.kg-1.min-1, respectively. A further eight patients (Group 4) received a Vf of 100 ml.kg-1.min-1 for 15 min, 75 ml.kg-1.min-1 for the next 15 min and 50 ml.kg-1.min-1 thereafter. In a further group of eight patients (Group 5), Vf was initially 25 ml.kg-1.min-1 for 10 min and was then switched off for the remainder of the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Pulmonary hamartoma.

Eighty-nine cases of pulmonary hamartoma were studied. There were 51 men and 38 women, with a mean age of 57.5 years (range 14 to 76 years). A histologic diagnosis from examination of the resection specimens was obtained in all patients who had operations. Moreover, transthoracic needle aspiration biopsies were performed in 40 patients, with a diagnostic result in 34 (85%). The hamartomas were equally distributed in the pulmonary lobes; mean transverse diameter at the time of diagnosis was 21.7 +/- 16.2 mm. Tumor size was independent of the anatomic localization, but it correlated with the age of the patients (p less than 0.01). Tumor growth was recorded in 15 of 31 patients who had follow-up (45%); mean expansion in transverse diameter was 3.2 +/- 2.6 mm per year during an average observation time of 4.1 years (range 1 to 20 years). Pulmonary symptoms were present in 35 patients (39%). Seventy-five patients underwent operations as follows: enucleation (54), resection (11), lobectomy (5), pneumonectomy (4), and bronchoscopic removal (1). Since most pulmonary hamartomas are nonexpanding or slowly growing neoplasms, it is concluded that operation is necessary only when expansion is recorded in young or middle-aged patients and in patients with pulmonary symptoms.

Adolescent↗
PubMed1991

Three genes which affect founding of aggregations in Polysphondylium pallidum.

PN6024 is an extraordinary mutant strain of the cellular slime mold Polysphondylium pallidum, characterized by having defects in many unlinked genes. New strains with altered development appeared spontaneously as aberrant clones of PN6024. Genetic crosses using the macrocyst sexual cycle were used to show that PN6030 (a clone like PN6024 in phenotype) carries mutations at two loci, emm and hge, whereas PN6031 (a clone of altered morphology) carries in addition a mutation at a third locus, mgt. hge and possibly mgt are linked to the mating type locus mat. The relatively high frequency of recombination between mat and hge is strong evidence that meiosis precedes macrocyst germination. The mutant genes themselves are of interest. A major effect of the emm-1 mutation is to remove the requirement for light to trigger aggregation. hge-1 greatly reduces the frequency of aggregation, whereas mgt-1 greatly increases it under standard conditions. None of these mutations interrupts later development leading to stalks and spore cells. It is hypothesized that all three genes act on steps immediately preceding the differentiation of the founder cells which initiate aggregation.

Crosses, Genetic↗
PubMed1990

Is mucaine an appropriate medication for the relief of heartburn during pregnancy?

A double blind comparative study comparing Mucaine, Mucaine without oxethazaine, and placebo was carried out with 50 patients with symptoms of heartburn during late pregnancy. We found that the 2 active treatments were more effective than placebo for the relief of heartburn, but there was no statistically significant difference between groups for the relief of nausea and regurgitation. There was a significant difference in the percentage of days of use of each medication, with the placebo being used least frequently. Although not statistically significant, for the 3 measures for which placebo differed from the active treatments, patients showed a better response to mucaine. This suggests that the addition of oxethazaine may be of benefit. The lack of statistical significance may be due to the relatively small number of cases, and the findings are promising. No side effects were recorded for any treatment.

Adult↗
PubMed1990

Primary hemangiopericytoma of the lung. Case report.

Hemangiopericytoma is a rare tumor, arising from pericytes. Its outcome is difficult to foretell, as the usual criteria for malignancy are unreliable in this neoplasm. Three cases of primary pulmonary hemangiopericytoma are presented and the pathologic and clinical aspects are briefly reviewed. All three patients were surgically treated, and two are still alive after 7 and 18 years without sign of recurrence or metastasis. The third patient, although still alive, has had three recurrences within 22 months and vertebral metastasis.

Female↗
PubMed1990

Immunohistochemical identification of neuron-specific enolase, synaptophysin, chromogranin and endocrine granule constituent in neuroendocrine tumours.

Immunohistochemical identification of neuroendocrine tumour markers in paraffin embedded material from 22 tumours (5 small cell carcinomas of the lung (SCCL), 12 carcinoids, 2 medullary thyroid carcinomas, 2 pheochromocytomas and one paraganglioma) with electron microscopically verified dense-core granules revealed neuron-specific enolase in all but one tumour, synaptophsin in 15/22 (2 SCCL and 6 carcinoids negative), chromogranin in 16/22 (all SCCL and one carcinoid negative), and endocrine granule constituent in 18/22 (4 SCCL negative). The Grimelius silver methods stained 13/22 (all cases of SCCL and 4 carcinoids negative).

Adrenal Gland Neoplasms↗
PubMed1989

Replicon size and rate of DNA replication fork movement are correlated in grasses.

In eukaryotes, most nuclear DNA replication proceeds bidirectionally from multiple origins of replication. A unit of DNA, replicated by two replication forks from a single origin, is termed a replicon. Using results from DNA fiber autoradiography we show a novel positive correlation between replicon size and the rate of replication fork movement in root meristem nuclei of 13 grass species. Although there is interspecific variation in replicon size, it is balanced by similar variation in the rate of replication fork progression.

Poaceae↗
PubMed1988

A mutant strain of Polysphondylium with defects in many genes.

PN6024 is a mutant strain of P. pallidum which appeared on selection for resistance to MDMP, an inhibitor of translation. It was found to be mutant in four other traits, being resistant to tubercidin, incapable of growth at 31.5 degrees C, abnormal in development, and slow growing at 25 degrees C. Genetic crosses using the macrocyst cycle showed that these five traits are controlled by five unlinked genes. The hypothesis is that movement of a transposon to multiple new locations caused these mutations. A difference in restriction fragment pattern between PN6024 and its parent PN600 support the hypothesis. Attempts were made to find conditions generating other strains like PN6024. Selection for growth in the presence of tubercidin yielded clones which resemble PN6024 in being developmentally abnormal as well as tubercidin resistant. Tubercidin treatment also increased the frequency of clones resistant to canavanine. It is suggested that tubercidin is mutagenic because it causes movement of the putative transposon, not because it generates point mutations. Growth under conditions of stress (at 31.5 degrees C, at 8 degrees C, in the presence of 2% ethanol) had at most an erratic effect in generating strains like PN6024. Three substrains appeared spontaneously in cultures of PN6024. These differed in developmental characteristics from each other and from the parent strain. It is suggested that they carry mutations in genes which control the choices between growth and aggregation, and between aggregation and encystment.

Crosses, Genetic↗
PubMed1988

Temperature and the cell cycle.

During the period between successive divisions, a cell traverses three stages of interphase: G1 (pre-synthetic interphase), S-phase (DNA synthetic interphase) and G2 (post-synthetic interphase). The time taken for all cells in a meristem to divide (the cell doubling time (cdt] decreases in response to an increase in temperature. For example, the cdt in root meristems of Zea mays decreases 21-fold as the temperature is increased from 3 to 25 degrees C. Whether all phases of the cell cycle alter proportionately with temperature has been ascertained by comparing data from the root meristem of five species: Pisum sativum, Helianthus annuus, Tradescantia paludosa, Allium cepa and Triticum aestivum. In three of the five species there is a disproportionate lengthening of the G1 phase at low temperatures. We suggest that arrest in G1 with the associated 2C amount of DNA, confers maximal protection on the genome of a somatic cell to the stress of low temperature. DNA replication has been studied at different temperatures for Helianthus annuus, Secale cereal and Oryza sativa. The rate of DNA replication, per single replication fork, increases when the temperature is raised, while the distance between initiation points (replicon size) remains constant. The temperature at which the cell cycle has a minimum duration is close to 30 degrees C in many species, and it seems that this optimum temperature is always near the upper temperature limit of the cell cycle. The rate of cell division determines the rates of organ and cell growth. Thus, temperature has a major effect on the way in which meristematic cells are deployed in organogenesis. The rate of organogenesis, in turn, determines the response of the plant to the growing season. We predict that species growing in sub-arctic conditions comprise cells with low DNA contents and hence have the potentialities for rapid cell cycles so that maximum advantage can be taken of a short growing season. Data from Triticum aestivum show that at 5 degrees C, nucleoli are large compared with those at 10-25 degrees C. These observations are consistent with high levels of RNA polymerase and cellular RNA found at low compared with high temperatures. These responses may be important in sustaining growth at 5 degrees C. Finally, the effects of temperature on developmental transitions are discussed. The picture that emerges is that more is known about low, as opposed to high, temperature as a morphogenetic switch but virtually nothing is known about cell cycle activity during such transitions.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗
PubMed1987

Mutants of Polysphondylium pallidum showing delayed modifications of glycoproteins are altered in a regulatory signal for development.

Binding of a monoclonal antibody, mAb293, to cell-surface glycoproteins of Polysphondylium pallidum is known to be blocked by L-fucose, and Fab of this antibody has been shown to inhibit intercellular adhesion of aggregation-competent cells. Mutants with delayed expression of the carbohydrate epitope, ep293, recognized by the antibody, have been shown to be retarded and altered in cell aggregation. The present study shows that ep293 is a modification of carbohydrate structure that is subject to regulation not only in mutant but also in wild-type cells; ep293 is expressed at an early stage of exponential growth in wild-type and only after 12 h of starvation in mutant PN6002. Proteins are already glycosylated before the epitope is expressed. The developmental regulation of pallidin, a lectin known to be an unglycosylated protein, was investigated in parallel with ep293 using a monoclonal antibody. Pallidin was expressed at about the same time as the carbohydrate epitope in cells of the wild-type as well as the mutant. These results indicate a regulatory signal to which various events are coupled. Induction of ep293 and expression of pallidin are two of these events, and mutants such as PN6002 are altered in the timing of the signal.

Antibodies, Monoclonal↗