Search PubMed⌕ Search

Biomedical subjects

C E Ford

Publications and source records attributed to C E Ford.

At least 55 records · Page 3Linked to original sources

Cardiovascular morbidity and mortality in HDFP patients 50-69 years old at entry.

Five-year morbidity and mortality in the Hypertension Detection and Follow-Up Program (HDFP) were stratified by age groups at entry to the study and by Stepped Care (SC) and Referred Care (RC) treatment groups. Although the incidence of stroke increased with age in both treatment groups, the greatest reduction in strokes for SC versus RC occurred in the older age groups: 44.3% for ages 60-69, 33.0% for ages 50-59, and 24.6% for ages 30-49. Conversely, the 30-49-year SC group showed a greater reduction of myocardial infarction than their RC counterparts, with only marginal benefit in the older SC patients. There was a lower rate of left ventricular hypertrophy (LVH) or cardiomegaly and a higher rate of reversal in those who had LVH or cardiomegaly at baseline in all SC age groups versus RC. HDFP patients 50 years and older at entry in the SC group had a substantial reduction in cardiovascular morbidity and mortality as compared with age-matched RC patients. It is likely that these benefits were the result of successful lowering of blood pressure.

Adult↗

Computerized spectral analysis of the interictal EEG in epilepsy.

Eight seizure patients without encephalopathy, frequent seizures, brain lesion, or medication intoxication had significant slowing of alpha-frequency activity, as compared to nonepileptic controls, that was evident in compressed spectral analysis but not in standard EEG. Those patients with cognitive or behavioral problems or taking more than one antiepileptic medication had a greater degree of slowing. Differences between seizure patients with and without cognitive or behavioral symptoms, and between specific antiepileptic drugs, were suggested but could not be assigned significance due to small numbers. The findings suggest that interictal changes in brain function that are not revealed by standard EEG may relate to observed changes in interictal behavior and cognition, and that computerized spectral analysis of the interictal EEG may be of value in the assessment of seizure patients before and during therapy.

Adolescent↗

Selective attention and rehearsal in the auditory short-term memory task performance of poor and normal readers.

The performance of poor and normal sixth-grade readers was compared on an auditory short-term memory task in two studies. In the first study, the effects of distraction, list length, and speed of stimulus presentation were investigated to test the hypothesis that the performance of the poor readers is affected by deficits in selective attention. Group differences in performance, however, were obtained for both distraction and no-distraction conditions. The second experiment examined the hypothesis that group differences may reflect differences in the use of rehearsal. In the second experiment, half the reading-disabled children and half the controls were provided with rehearsal training prior to completing the same short-term memory task a second time. Rehearsal training resulted in improved performance relative to children who were not trained; however, there was no rehearsal training X reading group interaction. The poor readers continued to show deficits in performance relative to the performance of control children. The results of these two studies suggest that deficits observed for poor readers on short-term memory tasks may reflect processing difficulties in some area that precedes rehearsal and affects performance under both distraction and no-distraction conditions.

Attention↗

Nondisjunction.

Explore the source record for details and available documents.

Animals↗

X-autosome translocation with a breakpoint in Xq22 in a fertile woman and her 47,XXX infertile daughter.

An unusual case is presented of a fertile woman heterozygous for a balanced X-autosome translocation t(X;12)(q22;p12) with a break-point (Xq22) in the critical region of the X chromosome. The karyotypes of her daughter, who is infertile, and one of her two sons are 47,XXX,t(X;12)(q22;p12) and 46,XY,t(X;12)(q22;p12) respectively. The literature on balanced X-autosome translocations in males and females involving both arms of the X chromosome is reviewed. All 23 of the 36 cases of females with balanced Xq-autosome translocation, that exhibited gonadal failure have a break-point between bands Xq13 and Xq26.U

Adult↗

A reciprocal translocation, t(6p+; 14q-), in the pig.

A reciprocal translocation, identified as t(6p+; 14q-), is described in a 38,XX intersex pig. It is the fourth reciprocal translocation to be reported for this species, whereas Robertsonian translocations, of frequent occurrence in cattle and sheep, are so far unknown in domestic pig breeds.

Animals↗

Cytogenetic observations on XX/XY chimaeras and a reassessement of the evidence for germ cell chimaerism in heterosexual twin cattle and marmosets.

Testicular preparations were obtained from 7 bulls, twins of freemartins, and 1 male marmoset, all proved XX/XY chimaeras. X and Y sex chromosomes were confidently identified in nearly all the 87 spermatogonia at mitotic metaphase and 1052 primary spermatocytes at diakinesis-metaphase examined: no cell was identified as containing two X chromosomes. The germ cell chimaerism previously reported in these species is therefore not confirmed. Cultures grown from presumptive somatic these species is therefore not confirmed. Cultures grown from presumptive somatic cells in the testes of two of the bulls yielded 248 identifiable mitotic spreads, all XY-type; cultures from the gonads of their freemartin twins yielded 442 mitotic spreads, all XX-type. Direct preparations from one freemartin gonad, however, yielded 3 XY mitotic spreads out of 18 examined. The conflicting evidence concerning germ cell chimaerism in cattle and marmosets is discussed, particularly in relation to reports of XX/XY bulls that have sired a great excess of daughters. The possibility that XX germ cells contributed to the functional spermatozoa of these bulls is not favoured by present information, but is not excluded.

Animals↗

Compartments and cell flows within the mouse haemopoietic system. I. Restricted interchange between haemopoietic sites.

Two chromosomally distinguishable haemopoietic cell populations were injected into lethally irradiated syngeneic recipients. The presence or absence of the T(14;15)6Ca reciprocal translocation (indicated by T6 marker chromosomes) did not affect the proliferation of a population. Wide disparities were found in the proportions of the two donor cell populations between animals and between the right and left femora of individual animals. This suggest (i) that there is, at most, a very limited interchange of proliferating cells and their precursors between the marrow of different bones; and (ii) that the number of clones proliferating in the bone marrow at any one time must be rather small; there was evidence that this number depended in part on the number of haemopoietic cells injected. Exchange between the mitotically active cell populations of spleen, thymus, lymph nodes and bone marrow was also limited, as shown by significant disparities in the proportions of the two donor populations proliferating in the different tissues of individual mice.

Animals↗

Compartments and cell flows within the mouse haemopoietic system. II. Estimated rates of interchange.

Part-body irradiated CBA mice were injected with CBA-T6 bone marrow. In this way a predominantly donor population was established in the femora while the marrow of the humeri remained largely (average 94%) of host origin. In animals examined cytologically up to 2 years later, no tendency was observed for the proportion of donor cells in the humeri to increase. Splenectomy had no effect on this. When femoral bone marrow from the experimental mice was injected into lethally (whole-body) irradiated recipients, cells originating from the primary host repopulated the lymph nodes to a disproportionate extent. Equilibration between the cell populations of femora and humeri occurred after re-exposure to 600 rad whole-body irradiation, but not after 100 rad or 350 rad; thus, regeneration of damaged bone marrow involved a significant contribution from extrinsic stem cells only after the highest dose of radiation. The data are compatible with an inflow of at most ten effective stem cells per humerus per day from the blood, and suggest a much lower figure. This means that few if any of the stem cells of peripheral blood enter the bone marrow and found haemopoietic clones. Evidence is adduced for the existence of a proliferating lymphoid sub-population in the bone marrow, contributing some 5-10% of the observed mitoses. The mitotic cells in the lymph nodes are replaced from marrow-derived progenitors at an estimated rate of 4-5%/day. The relevant data for the thymus are more variable, but suggest an average figure of 8-11%/day. Earlier data from mouse parabionts suggest a lower rate of inflow to the thymus.

Animals↗

Marker chromosome analysis of two mouse chimaeras.

Chimaeric mice were obtained by injecting embryonic (CBA/H-T6 X PDE)F1 cells into PDE blastocysts. Three of 15 young were overt chimaeras. One female and one male chimaera survived to adulthood and after completion of test breeding, which demonstrated chimaerism in the germ cells of both, they were killed for study when aged 32 and 33 weeks respectively. Chromosome spreads were scored for the presence or absence of the T6 marker chromosome in direct preparations from bone marrow, spleen, thymus, lymph nodes, Peyer's patches, corneas, gut epithelium and testes. Preparations from monolayer cultures of skin, kidney, ovary and gut from mitogen-stimulated blood cultures were scored in the same way. Both components of the chimaeras were identified in every one of 53 specimens studied, some of which, such as single lymph nodes, corneas, and segments of gut, may not have contained more than 10(5) proliferating cells. This result complements published evidence for fine-grained mixture obtained in morula-aggregation chimaeras by other methods and implies extensive cell movement during embryogenesis. Results obtained from the lymphomyeloid tissues show a clear partition into two groups in respect of the proportions of host-type to donor-type cells indentified. The one group consists of bone marrow, thymus and Peyer's patches, the other of spleen and lymph nodes. This result would be most simply explained in terms of two distinct stem cell pools and appears to conflict with the currently favoured hypothesis of a single stem cell pool for the whole lymphomyeloid complex located in bone marrow. Four groups of factors may, however, modify the relative representation of the two components in different lymphomyeloid sites: (1) The magnitude of embryonic founder populations. (2) Limited recruitment from the stem cell pool in post-natal life. (3) Variable size of clones produced by individual stem cells. (4) Differential cellular behaviour determined by genotypic differences.

Animals↗