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Biomedical subjects

B Dale

Publications and source records attributed to B Dale.

At least 109 records · Page 6Linked to original sources
PubMed1985

Sperm-oocyte interaction in the sea-urchin.

A study was made of the electrical and morphological changes in the sea-urchin oocyte during interaction with spermatozoa. The first event, a small step depolarization accompanied by a 20-40% decay in input resistance occurs within seconds of attachment. The evidence suggests that this electrical event is the result of sperm-oocyte fusion, and that the ion channels that lower the resistance across the oocyte-sperm complex are located in the sperm plasma membrane. This primary electrical event does not necessarily lead to sperm incorporation. A second, determinative, event occurs at 50 s, which leads to sperm entry and the formation of a cytoplasmic protrusion at the site of sperm entry. This second event probably results from the transfer of a soluble component from the spermatozoon into the oocyte cytoplasm, which leads to sperm incorporation and formation of the protrusion. The changes in the oocyte following insemination are compared with the events of egg activation.

Action Potentials↗
PubMed1984

Sperm-activated channels in ascidian oocytes.

Ionic channels activated during fertilization in the ascidian oocyte membrane have been studied using the single-channel recording technique. These channels, which we have called "fertilization channels," have a single-channel conductance of about 400 pS, a reversal potential of about O mV, and an open time of 2-30 msec. The open channel probability is about 0.2 at +20 mV and increases as the membrane is depolarized. The unitary conductance is among the largest hitherto observed in biological membranes.

Animals↗
PubMed1984

Problem drinkers' goal choice and treatment outcome: a preliminary study.

Thirty-seven problem drinkers, who had completed a 6-week residential programme which emphasises self-control and education, were classified into three groups. The patients leaving treatment with no measurable physical damage were classed as either controlled drinking choosers or abstinence choosers depending on their goal choice. The third group of patients, who showed physical damage, were strongly advised to remain abstinent after discharge. Follow-up for 1 year produced no significant outcome differences between the controlled drinking choosers and abstinence choosers, with patients in each group most likely to achieve their goal choice. The worst outcome, measured on several indices, was shown by patients strongly advised to abstain.

Adult↗
PubMed1983

Electrical response to fertilization in ascidian oocytes.

The fertilization potential of the ascidian oocyte has been studied using two intracellular electrodes. Two classes of oocyte were observed; low resting potential (RP) oocytes of -20 to -35 mV and high RP oocytes of -80 to -90 mV. The two types have comparable membrane resistance, falling in the range of 100-300 M omega, and both may be fertilized and develop normally, although the fertilization potential (FP) is different in the two cases. High RP oocytes give rise to step-like regenerative potentials which attain positive values, whereas low RP oocytes give rise to slower depolarizations that reach zero level. In both cases the FP was sometimes preceded by a small-step depolarization as normally observed in the sea urchin. Irrespective of the original RP, the membrane resistance always decreased to 1-10% of its initial value during the first few minutes of the FP plateau. In contrast when the membrane was depolarized to a comparable potential by current injection the membrane resistance did not decrease. Polyspermic fertilization was induced by removing the extracellular coats, aging the oocytes and using high densities of sperm. The FP in monospermic and polyspermic oocytes were comparable and we could not correlate additional sperm interactions with additional electrical events. Our results suggest that the plasma membrane in ascidian oocytes lacks intrinsic mechanisms, electrical or otherwise, to prevent polyspermic fertilization.

Action Potentials↗
PubMed1982

Transforming gene of a human leukaemia cell is unrelated to the expressed tumour virus related gene of the cell.

The virally encoded oncogenes (v-onc) of avian and mammalian retroviruses are the recombinant products of normal cellular genes (c-onc) and a retroviral genome. These cellular homologues have been highly conserved during evolution and are found in human DNA. The expression of at least one c-onc under the control of a viral promoter results in transformation of cells in a manner resembling that displayed by the v-onc counterpart; the inappropriate expression of c-onc in the absence of viral influences could likewise result in the malignant state. This proposal would be strongly supported by the presence of c-onc RNAs in a variety of human tumours were they not also demonstrable in normal tissues. The role of these RNAs in the oncogenic process remains unclear. Here we report that RNA homologous to the oncogene (v-abl) of Abelson murine leukaemia virus (A-MLV) is expressed in a unique human leukaemia in a fashion different from that of other human tissues and tumours. In addition, DNA from this tumour transforms NIH-3T3 cells at a high efficiency in a transfection assay. The transfected sequences are not related to the v-abl gene, but the NIH-3T3 transformants manufacture a transforming growth factor which behaves similarly to factors produced by A-MLV-transformed NIH-3T3 fibroblasts.

Abelson murine leukemia virus↗
PubMed1982

Loss of viral gene expression and retention of tumorigenicity by Abelson lymphoma cells.

Lymphomas induced by the Abelson murine leukemia virus (A-MuLV) were examined for the expression of biochemical and biological markers associated with A-MuLV transformation before and after in vivo growth in genetically distinguishable host mice. Although all tumors and clonal lines derived from them initially expressed the A-MuLV-encoded gag fusion protein p160, they ceased synthesis of this molecule after several weeks of growth in vivo as ascites tumors. Transplanted clonal lines continued to express the alloantigenic marker H-2b and the isoenzyme marker Gpi-1b of the donor tumor cells, indicating that the cells were of donor and not host origin. Examination of cellular DNA obtained from p160-positive and derivative p160-negative lines indicated that p160-negative clones had lost A-MuLV-specific proviral sequences as detected by hybridization with several probes. Although the clonal lines no longer expressed p160, they retained their malignant phenotype and continued to express the Abelson antigen, a cell surface marker associated with A-MuLV lymphomagenesis. Continued expression of the A-MuLV genome was not required for maintenance of oncogenic potential under these conditions of in vivo tumor growth.

Abelson murine leukemia virus↗
PubMed1981

Characterization of mouse cellular deoxyribonucleic acid homologous to Abelson murine leukemia virus-specific sequences.

The genome of Abelson murine leukemia virus (A-MuLV) consists of sequences derived from both BALB/c mouse deoxyribonucleic acid and the genome of Moloney murine leukemia virus. Using deoxyribonucleic acid linear intermediates as a source of retroviral deoxyribonucleic acid, we isolated a recombinant plasmid which contained 1.9 kilobases of the 3.5-kilobase mouse-derived sequences found in A-MuLV (A-MuLV-specific sequences). We used this clone, designated pSA-17, as a probe restriction enzyme and Southern blot analyses to examine the arrangement of homologous sequences in BALB/c deoxyribonucleic acid (endogenous Abelson sequences). The endogenous Abelson sequences within the mouse genome were interrupted by noncoding regions, suggesting that a rearrangement of the cell sequences was required to produce the sequence found in the virus. Endogenous Abelson sequences were arranged similarly in mice that were susceptible to A-MuLV tumors and in mice that were resistant to A-MuLV tumors. An examination of three BALB/c plasmacytomas and a BALB/c early B-cell tumor likewise revealed no alteration in the arrangement of the endogenous Abelson sequences. Homology to pSA-17 was also observed in deoxyribonucleic acids prepared from rat, hamster, chicken, and human cells. An isolate of A-MuLV which encoded a 160,000-dalton transforming protein (P160) contained 700 more base pairs of mouse sequences than the standard A-MuLV isolate, which encoded a 120,000-dalton transforming protein (P120).

3T3 Cells↗
PubMed1980

Serotyping of Campylobacter jejuni/coli.

Antisera were prepared from strains of Campylobacter jejuni/coli isolated from patients in six outbreaks of enteritis. Bactericidal antibodies, and agglutinating antibodies to heat-labile and heat-stable antigens, were demonstrated. These reactions were used to type a number of strains isolated from patients in each outbreak, and to distinguish 'epidemic' from 'non-epidemic' strains.

Campylobacter↗
PubMed1980

Serological response to Campylobacter jejuni/coli infection.

The antibody response to Campylobacter jejuni/coli infection was investigated in 59 patients involved in two outbreaks of milk-borne infection and in sporadic infections in the community. Agglutinins and complement-fixing (CF) antibodies were detected in nearly all these patients. Agglutinins were present in 25% of normal sera at low titres (not greater than 1/160) but CF antibody titres of 1/4 or 1/8 were present in only 2.0%. The agglutination reactions in convalescent sera were best developed with the homologous or an antigenically similar strain whereas the CF test, with sonicated organisms as antigen, was less strain-specific and was more suitable as a routine test. Antibody was present seven to 10 days after the onset of symptoms.

Agglutination Tests↗
PubMed1979

Membrane response to 1-methyladenine requires the presence of the nucleus.

Meiosis is re-initiated in starfish oocytes by the action of the hormone 1-methyladenine (1-MA). It is thought that the primary trigger is localised at the plasma membrane, and early changes reported are the activation of a Na+ pump and variation in membrane potential and conductance. We report here that external application of 1-MA results in an irreversible switching of the starfish oocyte membrane from one stable electrical state to another. This induced change requires the presence of the germinal vesicle.

Adenine↗
PubMed1979

Null cell chronic lymphocytic leukaemia.

Lymphocytes lacking receptors for sheep erythrocytes and surface immunoglobulin were present in the blood in large numbers at some stage in four cases of chronic lymphocytic leukaemia (which included a mother and son), and formed a substantial proportion of the circulating lymphocytes in other cases. These null cells possessed receptors for mouse erythrocytes. Other B-cell markers were also found on these cells. Serial studies showed a great variation in the number of null cells during the course of the disease (which may be associated with treatment), suggesting variation in the the maturation of leukaemic cells, and indicating that the surface marker complement may not reflect the constitution of the cell undergoing the original malignant change.

Aged↗