bluuebunny/crossref_metadata_2025 huggingface dataset:
TECHNOLOGY TRANSFER, APPROPRIATE TECHNOLOGY, AND CULTURAL RECEPTIVITY PROBLEMS
Authors: Okoro Greg I.
Published: May 2008

The prominent role of technology in economic development has made technology transfer a fertile area of research in recent times. Scholars of economic development often push the “late‐comer hypothesis” which emphasizes that LDCs can easily catch‐up with, and may even surpass, the advanced industrial nations. Yet in many situations, repeated efforts at implementing national economic agenda have failed to corroborate that theory. This article discusses some vexing difficulties and controversies surrounding the transfer process, and posits that unsuccessful technology transfer is attributable to factors which are rooted in cultural, economic, and political differences between the transferrer and recipient nations.
Photography: A Survey of New Reference Sources
Authors: Block Eleanor S.
Published: May 2008

What a difference a few years make! In the fall 1982 issue of Reference Services Review I described forty reference monographs and serial publications on photography. That article concluded with these words, “a careful reader will be aware that not one single encyclopedia or solely biographical source was included…this reviewer could find none in print…A biographical source proved equally elusive” (p.28).
Anorexia Nervosa and Bulimia: A Resource Guide
Authors: Baxter Pam M.
Published: May 2008

Medical and mental health professionals are in general agreement that the occurrence of anorexia nervosa and bulimia has increased dramatically during the past ten years. The revelation that public figures such as Karen Carpenter and Cherry Boone were victims has demonstrated that these debilitating illnesses occur more frequently than previously supposed. Not only has the number of relevant professional communications in psychology, psychiatry, and medicine multiplied, but popular periodicals, newspapers, and television have brought these psychiatric disorders to the attention of the general public. As a result, wards and clinics specializing in the treatment of eating disorders have opened in cities of even modest size. Support groups for sufferers and their families are becoming more common as the magnitude of these mental health problems is recognized.
Computerised colour measurement
Authors: Harding J.V.
Published: May 2008

Coloration costs as a percentage of a product's total manufacturing price have, in general, risen ten times faster than all other raw material costs in the last five years. The ever increasing need for the most cost‐effective use of pigments in colouring, coupled with the need to reduce machine down‐time while colour matching is taking place, has resulted in the rapid development of computer based technology to assist the colourist in his work.
Training for Word Processing—The Way Ahead
Authors: Tenne Ruth
Published: May 2008

In recent years the Manpower Services Commission (MSC), through its Training Services Division (TSD), has considerably extended its training operations for clerical and commercial staff. The rapid growth of office technology and its increasing impact on office functions and office skills led TSD to recognise this field as one of the major priority areas of its operating plan for the years 1980–81. As a result a project was launched aiming to:
Measuring the effect of training courses on the participants
Authors: Eskin F.
Published: May 2008

The subject of evaluating course effect has been a major source of controversy over a number of years in every professional field and organisational context. There has been much discussion, the development of a substantial literature, but little progress in action. The whole area of course evaluation is extremely complex, fraught with traps, pitfalls and unexpected blind alleys. It is not an issue which should be lightly tackled. The difficulties arise, not in the actual measurement, but in the definition, concepts, approaches and techniques that precede the measuring stage. Many attempts at evaluation have come to grief because measurement has taken place within the context of an inadequate conceptual framework.
All that glitters is not gold: The need for economic evaluation of supplies' options
Authors: Maynard Alan
Published: May 2008

The system for the provision of supplies in the UK National Health Service is being continually ‘redisorganised’ in an effort to improve efficiency and get better value for money. Alongside these reorganisations, the regulation of the supply of pharmaceuticals to the NHS is also being altered. What are the differences between these two processes and can any obvious lessons be learnt from the ways in which the NHS seeks to control the prices, qualities and quantities of products in these two closely related areas of supplies?
The Laboratory Data Management Computer — The appropriate source of cost reports in hospital budgeting systems
Authors: Dale G. , Fleetwood J.A. , Johnson B. , Walton D.R.
Published: May 2008

With the introduction of systems of financial management, departmental computers are needed to provide the cost analysis reports from clinical biochemistry and other laboratory departments. To avoid unnecessary duplication of effort, it is important that laboratory data management computers can produce the cost reports required. Any viable system should take account of the additional costs involved in emergency work, the processing of high risk samples etc. Such a system is described, and an indication of the flexibility of the cost analysis software is given. The problems are largely logistical, as the computer searches needed are lengthy, and at present are performed out of normal working hours.
‘Accountability’, Hospital Doctors and Disciplinary Procedures
Authors: McGregor Angus
Published: May 2008

In the first part of this paper, the significance of the word ‘accountability’ is explored in relation to the employment of hospital doctors, as in‐practice doctors and management attach very different meanings to it. The paper takes the view that, essentially, management views doctors as particularly expensive and difficult senior employees, while doctors see themselves as accountable only to their patients. In the second part, the processes for disciplining doctors are described in relation to the three main types of problem — sickness; personal misconduct; and professional misconduct and incompetence.
A Constitutional Framework for Ethical Review Committees
Authors: Hunt Geoffrey
Published: May 2008

Ethical committees which review medical research need consitutions to help ensure continuity, clarity and consistency of purpose, and moral soundness. An adequate constitution must embody decision procedures which reflect a concern for clearly defined remit and scope, independence from bias and compromise, and accountability to the public, the health authorities and the researchers.
Use of IT to Improve Care and Save Resources: Why Present Proposals are Worrying, and Why the UK is Losing Ground
Authors: de Dombal F.T.
Published: May 2008

Improvements in the quality of care are com‐patible with resource saving — but to achieve these desirable aims, doctors' performance must change. More attention should be paid to this aspect of health care management. However, interest is far greater overseas than in the UK at regional or national level. The current UK lack of interest (at Government level) in the potential of information technology for clinical decision‐support is already prevent‐ing patient, physician and the public purse front benefiting from a concept originally promoted in the UK but now more widely adopted abroad. Unless some sensible means can be devised for coordinating clinical decision support systems with audit, resource management initiatives and HISS — and ensuring some structure which will offer both clinicians and managers some practical benefit — the present vast expenditure on IT in the National Health Service may merely repeat (at a hundred times the cost) the unfortunate 1960s experiments with computers and public money.
Comment
Authors: Hall Ray
Published: May 2008

Early in November 1982 I commissioned the article here published. LA's Executive Co‐ordinating Committee recommended to council on January 18 1983 that the association approach the Electoral Reform Society about running council elections, and that the use of a transferable vote be considered. Readers should not assume that such percipience in ECC matters can be maintained, or that I am a member of the Social Democratic Party. Editor
Commonplaces
Authors: Bunch Allan
Published: May 2008

Community festivals ‐ Local community festivals can be a lot of fun to those who participate in them and, incidentally, help to strengthen community awareness and develop skills, but for those called upon or lumbered with the job of planning and organising them, they can be a nightmare. The task is made easier by the existence of an excellent little book, the Community festivals handbook, which has just been released in its 3rd edition by Community Projects Foundation. The kind of festival covered by this essentially practical handbook is that in which there is a concentrated mixture of activities lasting for a day, a weekend or maybe a week, based in a particular locality, with some emphasis on community participation. It would also be relevant to other forms of community‐based work, such as running a barbecue or a social, trying to raise money, expanding the activities of an adventure playground, setting up a city farm or engaging in a local campaign. The handbook can serve as a checklist of ideas and aspects that need to be thought about from the reasons for running a festival to financial ‘post‐mortems’. On the way the book covers organising committees, involving local people, planning, publicity, legal and administrative aspects, site management and catering. An excellent guide that won't guarantee success but, if you follow its advice, will make it more possible. Costs £2.00 including postage from CPF, 60 Highbury Grove, London N5 2AG.
RENAL EPITHELIAL HYPERPLASIA: FAILURE TO DEMONSTRATE A HUMORAL CONTROL FACTOR
Authors: Johnson Horton A. , Roman Jose M. Vera
Published: May 2008

An attempt was made to demonstrate a humoral factor controlling renal hyperplasia following unilateral nephrectomy. Rapid mixing of blood between parabiotic rats was obtained through carotid artery‐jugular vein cross cannulation. These experiments showed no evidence for the passage from a nephrectomized rat to an intact rat of a humoral agent controlling compensatory growth of the kidney.
A STUDY OF INEFFECTIVE ERYTHROPOIESIS IN SIDEROBLASTIC ANAEMIA AND ERYTHRAEMIC MYELOSIS
Authors: Wickramasinghe S. N. , Chalmers D. G. , Cooper E. H.
Published: May 2008

Erythropoiesis has been studied in three patients with sideroblastic anaemia and one case of erythraemic myelosis. The marrows showed erythroid hyperplasia, plasma iron turnover was high, red cell iron utilization low, and retention of 59Fe prolonged in the marrow. A combined quantitative cytochemical and autoradiographic analysis showed an accumulation of early polychromatic cells in G2 and the presence of several cells which were apparently arrested after a period in DNA synthesis. DNA synthesis was rarely seen in cells with pronounced siderotic deposits. These results indicate the presence of ineffective erythropoiesis with a disturbance in the progress of early polychromatic cells through interphase, probably leading to intra‐marrow cell death. In erythraemic myelosis there was also a reduced red cell production due to faults of cell division; the nature and consequence of the bizarre forms of cell replication are discussed.
THE NUMBER AND POSSIBLE FUNCTIONS OF DNA‐SYNTHESIZING CELLS IN HUMAN BLOOD
Authors: Killmann Sven‐Aage
Published: May 2008

The number of DNA‐synthesizing cells in the blood of patients with various disorders was studied autoradiographically after incubation of blood in vitro with [3H]thymidine. The DNA‐synthesizing cells were cytologically assigned to the following categories: erythroid, myeloid, lymphoplasmacytoid and unidentifiable (monocytoid or blast‐like) cells.

The following patient categories were studied: mitral valvular disease (samples obtained from peripheral vein, pulmonary artery and left auricle), ‘autoimmune diseases’(systemic lupus erythematosus, schleroderma, Hashimoto's thyroiditis, immunohaemolytic anaemia), patients with depressed haemopoiesis (aplastic anaemia, nitrogen‐mustard induced bone‐marrow hypoplasia) and with increased haemopoiesis (haemolytic anaemia, pernicious anaemia before and during initial vitamin‐B12 therapy, red‐cell mass regeneration after haemorrhage or iron deficiency) and patients with bacterial infection.

In all conditions studied, the number of labelled monocytoid and blast‐like cells varied between 0 and 4/μl. Similarly, the number of labelled lympho‐plasmo‐cytoid cells was consistently low (0–8/μl) in all cases studied except two, where values of 37 and 63/μl were found. Both these patients had severe bacterial infections.

The function(s) and potential(s) of these cells are discussed. The fate of the blast‐like and monocytoid cells remains obscure. The lympho‐plasmocytoid cells probably serve an immunological function, perhaps by disseminating immune responses. Whether or not some DNA‐synthesizing cells in the blood are haemopoietic stem cells cannot be decided from the available evidence.
EFFECTS OF INCREASED PARTIAL PRESSURES OF OXYGEN, NITROGEN AND HELIUM ON CELLS IN CULTURE
Authors: Stephenson N. G.
Published: May 2008

The effects of gas‐phase oxygen, nitrogen and helium at superatmospheric as well as at atmospheric partial pressures have been studied, using both normal and malignant cells.

The ability of certain types of cells in monolayer cultures to proliferate when exposed to high or low oxygen tensions, and to recover when cultured further under more optimal conditions, has been assessed.

The presence of an inert gas at high partial pressure permits survival of various types of cells in culture at much higher oxygen tensions than would otherwise be possible. A tentative explanation for this phenomenon is provided and its significance discussed.
SOME MORPHOLOGIC AND KINETIC STUDIES OF THE DEVELOPING ERYTHROID CELLS OF THE COMMON GOLDFISH, CARASSIUS AURATUS
Authors: Iorio Robert J.
Published: May 2008

Developing erythroid cells of the goldfish Carassius auratus were obtained from kidney prints and from smears of the peripheral blood. All preparations were stained with the May‐Grunwald Giemsa technique. Developing cells were divided into six different stages. The criteria used to stage the cells were degree of chromatin condensation, degree of basophilia, nuclear:cytoplasmic ratio, and cell shape. The morphology of the maturation sequence for erythroid cells in this organism was similar to that found by other workers in other non‐mammalian vertebrates.

Fish received intraperitoneal injections of tritiated thymidine, tritiated uridine or tritiated leucine so that the stages involved in DNA synthesis, RNA synthesis and protein synthesis could be determined by means of autoradiography. For the tritiated thymidine studies the per cent labeled cells per stage from four different series receiving 0.5, 1.0, 3.0 or 6.0 μCi/g body weight were pooled, since subjecting the average per cent labeled cells per stage at the lowest and at the highest dosages to Student's t‐test showed no significant differences. In all four series the fish were killed 2 hr, 12 hr and daily, 1–8 days post‐injection. The 3H‐TdR studies showed that stages I‐IV were engaged in DNA synthesis; they also showed that about 5 days were required for the stage V cell to become a mature erythrocyte (stage VI cell).

Tritiated uridine was injected at a dosage of 5.0 μCi/g body weight and animals were killed 1/2, 1, 3 and 6 hr post‐injection. Grain counts showed that stages I‐IV are engaged in RNA synthesis and that the rate of this synthesis decreased as maturation proceeded.

Tritiated leucine was administered at a dosage of 5.0 μCi/g body weight, and fish were killed 45 min and 3 hr post‐injection. Grain counts indicate that stages I‐V are engaged in the synthesis of protein (assumed to be globin). The fact that DNA and RNA synthesis ceased with stage IV cells while protein synthesis continued into stage V cells indicated that the mechanism responsible for protein synthesis in stage V cells was produced at an earlier stage and was self‐sustained for about 5 days.
MEGAKARYOCYTOPOIESIS IN MICE
Authors: Jr T. T. Odell , Jr E. A. Burch , Jackson C. W. , Friday T. J.
Published: May 2008

Megakaryocytopoiesis was investigated in young RFM/Unf mice by determining in autoradiograms of marrow smears the labeling index (percentage of cells labeled) of morphologic stages of megakaryocytes at intervals after a single injection of tritiated thymidine. The total maturation time of recognizable megakaryocytes is estimated to be 50–57 hr. The average times spent in the Type I (immature) and Type II (mature) compartments are, respectively, 15 and 42 hr, but we believe that there is a wide variation in these periods among individual megakaryocytes. The frequencies of megakaryocytes of Types I, II and III are 10, 86 and 4%, respectively.
THE REACTIVITY OF HUMAN SMALL LYMPHOCYTES IN CULTURE: THE EFFECTS OF CONCENTRATION AND DURATION OF EXPOSURE TO PHYTOHAEMAGGLUTININ
Authors: Simons M. J. , Fowler R. , Fitzgerald Margaret G.
Published: May 2008

The reactivity to phytohaemagglutinin (PHA) of column purified human small lymphocytes in culture has been quantitated by tritiated thymidine uptake into newly synthesized DNA. Using this system the dependence of lymphocyte response on PHA concentration, purity of PHA and duration of exposure was demonstrated in detail. Stimulation of lymphocytes was found to occur within 10 min of the addition of PHA. Maximal responsiveness occurred with exposure to PHA for 10 hr, while further exposure resulted in a sub‐maximal response.
GROWING BONES ON THE COMPUTER—SOME PITFALLS OF A COMPUTER SIMULATION OF THE EFFECTS OF RADIATION ON BONE GROWTH
Authors: Kember N. F.
Published: May 2008

The linear arrangement of the proliferating cells in the growth cartilage of bone provides an apparently simple system for studying the relationship of cell kinetics to a gross endpoint, i.e. bone growth. The system has been reduced to a simple computer model which follows the effects of radiation on the growth of fifty or one hundred individual cartilage columns.

When the computed data were compared with experimental curves some factors were discovered that had been omitted from the original model. A revised model proved of limited value in sorting out the relative importance of competing kinetic parameters but indicated some directions for future experimental studies.
DISTRIBUTION AND MULTIPLICATION OF COLONY FORMING UNITS FROM BONE MARROW AND SPLEEN AFTER INJECTION IN IRRADIATED MICE
Authors: Lahiri S. K. , Van Putten L. M.
Published: May 2008

The distribution and proliferation of CFUs from bone marrow and spleen cell suspensions were followed after injection in lethally irradiated isogeneic mice. It was found that a larger proportion of the injected bone marrow CFUs than of the spleen derived CFUs could be recovered from the recipient's spleen and femur. This consistently higher recovery points to the conclusion that a larger fraction of bone marrow‐derived CFUs than of spleen‐derived CFUs is capable of producing daughter CFUs, most likely due to a commitment to early differentiation of many spleen CFUs.
IN VIVO ORGAN RECONSTRUCTION FROM CELLS CULTURED IN VITRO
Authors: Wada Akira , Pollak O. J.
Published: May 2008

Dispersed primary tissue culture cells from adrenal, aorta, heart and cornea of adult rabbits were placed into diffusion chambers. The chambers were implanted into serologically compatible litter mates.

Chimaeric aggregates resembling embryonal organs formed in the chambers within 3 weeks. The ‘adrenal’had two to three cortical zones to both sides of a medulla. The ‘aorta’had a central fibromuscular layer and a surface layer of endothelial cells. The ‘heart’consisted of a muscular layer coated with endothelial cells; the aggregate assumed a chamber‐like shape. The ‘cornea’had a loose matrix covered on the convexity by epithelial cells.

Upon transfer of the aggregates from in vivo to in vitro culture, cells dispersed within 1 week and propagated as a mixed population.

Analysis of the phenomenon has been attempted and the course of future studies suggested. The study contributes to the discussion of cell automatism.
IN VITRO INCORPORATION OF 3H‐THYMIDINE, 3H‐URIDINE, 3H‐LEUCINE AND 3H‐MELPHALAN BY PLASMACYTOMA PLASMA CELLS
Authors: Ponti G. B. , Eridani S. , Astaldi G. , Giangrande A.
Published: May 2008

Bone marrow plasma cells from fifteen cases of multiple myeloma, immunologically typed, were incubated with different tritiated compounds.

The labelling index with tritiated thymidine is generally low, while the mean grain count is fairly normal in the active cells. The labelling index of 3H‐uridine and 3H‐leucine was very high, while the mean grain count per cell lies within the normal range.

The results obtained with 3H‐phenylalanine‐mustard (melphalan), which is a drug used in the treatment of the plasmacytoma, show also incorporation values roughly comparable to those of 3H‐leucine.

The present data seem to support the clinical use of melphalan as a compound that is actively incorporated into the plasma cells of plasmacytoma although inhibition of protein synthesis due to specific binding to protein was not demonstrated.
A METHOD FOR QUANTITATION OF PROLIFERATIVE INTESTINAL MUCOSAL CELLS ON A WEIGHT BASIS: SOME VALUES FOR C57BL/6
Authors: Hagemann Ronald F. , Sigdestad Curtis P. , Lesher S.
Published: May 2008

A method for determining the number of intestinal mucosal crypts, S cells, and total proliferative cells, on a weight basis has been presented. The number of crypts was obtained (following injection of tritiated thymidine) by dividing the disintegrations per minute (dpm) per mg intestine by the dpm per crypt. Multiplication of the number of crypts per mg by the number of labeled cells per crypt (determined radioautographically) resulted in the number of S cells per mg intestine. Division of the number of S cells per mg by the fraction of proliferative cells in S (obtained by cell cycle analysis) resulted in the number of proliferative cells per mg intestine.

Values for duodenum, jejunum, and ileum of male C57BL/6 mice are given.
AREA RELATIONS BETWEEN LABELING INDEX CURVES FROM MULTICOMPARTMENT CELL KINETICS MODELS.
Authors: Buchal R. N. , Phillips D. L. , Trucco E.
Published: May 2008

The study of the multicompartment models in cell kinetics can be simplified by the use of a conservation law relating the integrals, with respect to time, of labeling index in various compartments. We present a proof of the conservation law directed to the nonmathematician, as well as four applications from biology. The first demonstrates a contradiction, which biologists have yet to resolve, between a certain biological model and experimental results. The second and third are simpler proofs of results already proven by other techniques in the literature. The fourth is a result which appears to be new.
THE KINETICS OF CELL PROLIFERATION IN THE TRACHEOBRONCHIAL EPITHELIA OF RATS WITH AND WITHOUT CHRONIC RESPIRATORY DISEASE
Authors: Wells A. B.
Published: May 2008

Labelling indices of the tracheobronchial epithelia of conventionally‐derived rats with chronic respiratory disease (CRD) and minimal‐disease rats without CRD have been determined. The duration of the DNA synthesis phase (ts) computed from the percentage of mitoses labelled at various intervals of time after injection of tritiated thymidine was 7 hr: tG2 was 3.5 hr. Using the measured value of ts and the labelling indices, the mean turnover times of the tracheobronchial epithelia in three groups of six 5‐week‐old conventionally‐derived rats were calculated to be 11.2, 14.6 and 22.4 days, while in similar groups of 5‐week‐old minimal‐disease rats the turnover times were found to be 24.3, 36.5 and 41.6 days. The majority of cell divisions in the tracheobronchial epithelium of these minimal disease rats were probably required for growth rather than renewal. The mean turnover time of this tissue in 5‐week‐old Syrian hamsters was 73 days.

The cells of the rat tracheobronchial epithelium have been classed as basal or superficial, depending on their shape and proximity to the basement membrane. The mean turnover time of the basal cells in 5‐week‐old minimal‐disease rats was 11.7 days calculated from labelling indices. The migration method of Brown & Oliver (1968) gave a similar value for the basal cells in minimal‐disease rats, and a value of 9.5 days for the basal cells in a group of conventionally‐derived rats. The mean turnover time in the latter was only 5.4 days if two rats with tracheobronchitis were included. Consideration of the slow rate of fall in mean grain count over labelled cells at intervals of time after labelling and the calculated turnover times suggests that the proliferative fraction of the basal cell population is close to unity. Well‐labelled cells were still present in both basal and superficial populations in the minimal‐disease rats at 10 days after labelling.

The marked effects of CRD on cell proliferation in this epithelium are emphasized and the significance of this in relation to published work is discussed.
CELL CLASSIFICATION AND KINETIC ASPECTS OF NORMOBLASTIC AND MEGALOBLASTIC ERYTHROPOIESIS
Authors: Killmann Sven‐Aage
Published: May 2008

Mitotic indices and 3H‐thymidine flash labelling indices have been determined in a total of 6000 erythroid cells from patients with megaloblastic anaemia (vitamin B12 deficiency) and 4000 erythroid cells from patients with increased, normoblastic erythropoiesis. In the anaemic states there is a lack of mitoses in the more mature erythroid compartments relative to the number of mitoses in the early erythroid precursors; this must reflect skipped division and/or cell death in the later precursors. In order to further locate the deficit of mitoses, erythropoietic cells were subdivided in a way which aimed at stratifying them according to cell generations. It appears that there are four consecutive generations of recognizable proliferating red cell precursors. Balance considerations of mitotic figures suggest that in stressed normopoiesis all cells which enter generation III divide, whereas only about one‐half of cells leaving generation III divide again in generation IV. In megaloblastic erythropoiesis it appears that only about one of three cells which leave generation III divide in generation IV. The data suggest that in megaloblastic anaemia, skipped division and/or cell death to a large extent take place in generation IV or at the transition from III to IV.

In normoblastic erythropoiesis, the ratio labelled cells/mitotic cells is rather independent of cell maturation. In contrast, this ratio varies considerably in megaloblastic erythropoiesis, from 25:1 in early forms to 4‐5:1 in late forms. As an explanation of the lack of mitoses, relative to cells in DNA‐synthesis, in the early stages and the relative surplus of mitoses in the late stages it is proposed that cell cycle and cytological boundaries do not coincide in all cells. The present observations can be accounted for if a significant fraction of cells change their morphology (from basophilia to polychromasia) between their DNA‐synthesis phase and the subsequent mitosis. It cannot be decided whether in addition there is a death function between DNA‐synthesis and mitosis in the large basophilic megaloblasts, megaloblastic system could absorb a direct entry from the large basophilic cells amounting to perhaps about one‐half of the flux through the S‐pool of the large basophilic cells without being more dominated by very large cells than is actually the case; still, in large measure this will depend on the time from entry into the polychromatic pool until the subsequent mitosis or possible cell death. The alternative is a significant death function between S‐phase and mitosis at the level of the large basophilic E1‐E2 cells (generation I + II).
HYPODIPLOID METAPHASE FIGURES IN HUMAN LYMPHOCYTE CULTURES TREATED WITH COLCEMID
Authors: Fitzgerald P. H. , Brehaut Loreen A.
Published: May 2008

A small proportion of dividing human lymphocytes exposed to colcemid continued cytokinesis in spite of partial or complete destruction of the mitotic spindle which made normal chromosome distribution impossible. At low concentrations of colcemid the cells divided into two, three, or more parts about chromosome aggregates, to form separate, apparently intact units, often with very low chromosome numbers. Greater concentrations of colcemid caused a more even dispersal of the chromosomes, and the cells tended to divide into two parts, between which the chromosomes were more or less equally distributed on a random basis.

This abnormal nuclear division is viewed in relation to the many known effects of colchicine and colcemid on mitosis and other stages of the cell proliferation cycle.
CHALONE CONTROL OF MITOTIC ACTIVITY IN SEBACEOUS GLANDS
Authors: Bullough W. S. , Laurence Edna B.
Published: May 2008

Extracts of skin with sebaceous glands contain a substance which inhibits mitotic activity in sebaceous glands both in vivo and in vitro. This substance is neither the epidermal chalone nor the melanocyte chalone, both of which are also present in skin extracts. However, it resembles these other chalones in that it is water soluble, is precipitated by ethanol, is activated by the two stress hormones adrenalin and hydrocortisone, and is not species specific. It is present within the sebaceous glands, and it is evidently a sebaceous gland chalone.
DIURNAL VARIATION IN THE LABELING INDEX OF MOUSE EPIDERMIS: A DOUBLE ISOTOPE AUTORADIOGRAPHIC DEMONSTRATION OF CHANGING FLOW RATES
Authors: Crube D. D. , Auerbach H. , Brues A. M.
Published: May 2008

A diurnal rhythmicity in the labeling index was observed in the epidermis of hairless mice, injected with either 14C‐ or 3H‐thymidine, at different times during a 24 hr period.

A modified autoradiographic technique, using 14C‐ and 3H‐thymidine and two overlying emulsion layers, makes it possible to clearly differentiate synthesizing cells which are singly labeled with either carbon‐14 or tritium, and cells labeled with both isotopes. At various times during a 24 hr period, hairless mice were injected with thymidine‐2‐14C and colcemid, followed at 2 or 3 hr by a second injection of 3H‐thymidine. The labeling indices were calculated for the 14C‐ and 3H‐thymidine injection times. These labeling indices were consistent with the control, single isotope, labeling indices and exhibited the same diurnal rhythm.

Cells singly labeled with 3H‐ or 14C‐thymidine have either started or completed DNA synthesis during the interval between the two injections. Flow rates into and out of DNA synthesis, throughout the 24 hr period, can be calculated from these singly labeled cells. The flow rates varied rhythmically throughout the day and paralleled changes in the labeling indices. The influx and efflux flow rates, at all times measured, were not equal. The influx flow rate was reflected in the efflux rate at a time later equal to the duration of S.

By means of these flow rates, the per cent of cells in DNA synthesis was calculated for each hour during a 24 hr period. The resulting labeling index curve matches the observed 24 hr diurnal rhythm in labeling indices. By extension of these flow rates through mitosis, the resulting mitotic index curve is comparable to the reported 24 hr diurnal rhythm in mitotic indices.
THE EFFECT OF POLYCYTHAEMIC SERUM ON THE PROLIFERATION OF RAT BONE MARROW CELLS IN VITRO
Authors: Kivilaakso E. , Rytömaa T.
Published: May 2008

The effect of experimental polycythaemia on the rate of proliferation of erythrocytic precursor cells was investigated by means of an in vitro technique. The serum obtained from polycythaemic rats was found to inhibit significantly 3H‐thymidine incorporation in normal rat bone marrow cells in vitro, as compared with normal serum. Autoradiographic analysis revealed that this inhibition resulted from a reduction in the number of labelled bone marrow cells. The inhibition proved to be specific to the erythrocyte precursor cells; the labelling index was reduced in the erythrocytic cell population by 21–50% (P < 0.001) at different incubation times, while the effect on the granulocytic cell population was negligible. It is deduced that an inhibitor substance responsible for the effects observed is present in polycythaemic serum. It is proposed that this factor is the ‘erythrocytic chalone'. The results support the general view that triggering of stem cells is not the only mode of regulation of erythropoiesis, but that the rate of proliferation of the precursor cells in the erythron is also regulated.
THE DEVELOPMENT OF FIBROBLAST COLONIES IN MONOLAYER CULTURES OF GUINEA‐PIG BONE MARROW AND SPLEEN CELLS
Authors: Friedenstein A. J. , Chailakhjan R. K. , Lalykina K. S.
Published: May 2008

In monolayer cultures of guinea‐pig bone marrow and spleen the development of discrete fibroblast colonies takes place on days 9–12. The linear increase in the number of colonies with increasing numbers of explanted cells and the distribution of male and female cells in mixed cultures support the view that fibroblast colonies are clones. The concentration of colony‐forming cells in bone marrow and spleen is approximately 10‐5. Bone marrow culture (but not spleen culture) fibroblasts are capable of spontaneous bone formation in diffusion chambers. Fibroblasts from both bone marrow and spleen cultures are inducible to osteogenesis in diffusion chambers in the presence of transitional epithelium.
CELL CYCLE PROPERTIES OF DIFFERENTIATING SPERMATOGONIA IN ADULT SPRAGUE‐DAWLEY RATS
Authors: Huckins Claire
Published: May 2008

The duration of the mitotic cycle and of its components was analysed for each of the six successive generations of differentiating spermatogonia (A1, A2, A3, A4, intermediate and B), using radioautographed whole mounts of seminiferous tubules from testes of adult Sprague‐Dawley rats. Cell cycles were determined from two successive waves of per cent labeled metaphases obtained during the period of 81 hr after a single dose of 3H‐thymidine. Except for the A1 spermatogonia, all spermatogonial types (A2 to B) had similar cell cycle durations of 41‐42.5 hr and comparable pre‐DNA synthesis phases (G1) of 11‐13 hr. Although the combined duration of DNA synthesis (S) and the post‐synthesis phase (G2) remained identical for all the cell types including A1, there was a progressive lengthening of the S period at the expense of G2 during the process of spermatogonial maturation. This change was most marked during the transition from A1 to A3 spermatogonia when the S period increased from 14 hr to 21 hr, and the G2 phase shortened from 13 hr to 7.5 hr. This feature seems to be unique to germ cells and may be associated with an increasing amount of heterochromatin in the nucleus. Excluding the development of type A1 cells, the entire process of spermatogonial maturation lasted for 208 hr. Combined data on cell cycle times indicated that every 313 hr or 13 days, a new sequence of spermatogonial differentiation was initiated by the A1 cells. This was equivalent to the duration of one ‘cycle’ of the seminiferous epithelium as measured by other techniques.
THE SPERMATOGONIAL STEM CELL POPULATION IN ADULT RATS
Authors: Huckins Claire
Published: May 2008

Radioautographed whole mounted seminiferous tubules from adult rat testes were used to analyse undifferentiated type A spermatogonia at various intervals up to 81 hr following a single injection of 3H‐TdR. the data obtained led to the identification of the spermatogonial stem cell and to the formulation of a new model for spermatogonial renewal and differentiation.

Undifferentiated type A cells were morphologically alike, but were topographically classified as (1) isolated or (2) paired and aligned. Although labeled isolated A cells were scattered over most stages of the seminiferous epithelium, their proliferative activity varied with the stage; their labeling index was 20‐30% in stages I and II, but less than 1% in stages VII and VIII. By tracing the labeled divisions of isolated A spermatogonia in time, it was seen that some daughter cells became separated from one another to form two new isolated cells, while others remained together as paired A spermatogonia. Analysis of two successive waves of labeled mitoses revealed that most paired A spermatogonia continued to proliferate forming four aligned A cells, many of which divided again to produce a chain of eight and so on. the greatest incidence of labeling among paired and aligned A spermatogonia occurred in stages XIII‐III. In stage I, where the labeling index was 50%, the calculated proliferative fraction was 1 for these spermatogonia. Between stages II and V, they began to leave mitotic cycle, and during stage V this entire cohort morphologically transformed into A1 spermatogonia. Labeled metaphase curves for undifferentiated A spermatogonia were distinct from any of the curves previously constructed for the six classes of differentiating spermatogonia, especially because of particularly long S and G2 phases in the former. the cell cycle time of paired and aligned A cells was 55 hr, compared to an average of 42 hr for differentiating types A2 to B.
MECHANISM OF EOSINOPHILIA
Authors: Spry Christopher J. F.
Published: May 2008

Eosinophil leucocyte production was studied in the bone marrow of normal rats and rats given single injections of Trichinella spiralis larvae which stimulated eosinopoiesis. the development sequence of eosinophils in the bone marrow was based on morphological criteria combined with studies of the extent of eosinophil labelling after injections of tritiated thymidine. the proliferative compartment contained at least three recognizable steps in eosinophil development which were defined.

There was a delay of 23 hr after injection of larvae before the proportion of eosinophils in the bone marrow increased and it had doubled by 49 hr. the mitotic index increased by a factor of 3 after stimulation. Estimates of the cell cycle parameters were made for marrow eosinophils 1‐3 days after stimulation, using the technique of analysing labelled mitoses. the results were compared with a similar group of normal rats, and were processed by using a computer program. Marrow eosinophil cell cycle time was 30 hr in normal rats and 9 hr in stimulated rats, and this acceleration was associated with a reduced spread of cell cycle times. the number of eosinophil cell divisions and the transit times for each compartment in normal and stimulated rats were estimated. This showed that the stimulus may have resulted in five or six additional divisions among the youngest eosinophils in the dividing compartment. From these figures an outline of eosinopoiesis in the marrow of normal and stimulated rats is proposed.
INCORPORATION OF TRITIATED THYMIDINE INTO THE SKIN AND HAIR FOLLICLES
Authors: Potten Christopher S. , Jessup Barbara A. , Croxson Mary B.
Published: May 2008

Diurnal fluctuations in incorporation of tritiated uridine and tritiated thymidine are reported for full thickness skin and its two proliferative populations, the epidermal basal layer and the hair follicle germ or matrix. Recently developed techniques whereby these two populations can be studied independently were utilized. Resting (unplucked) skin and skin in the middle of the hair growth cycle (10 days after plucking) was studied. the diurnal fluctuations differed at these two stages of the hair cycle. Generally a single minimum level of activity was observed shortly after the beginning of the dark period of the day, i.e. after 18.00 hours.
THE ROLE OF BONE MARROW OF X‐IRRADIATED MICE IN THYMIC RECOVERY
Authors: Blomgren Henric
Published: May 2008

The influence of the bone marrow on the repopulation of the thymus in X‐irradiated mice has been investigated.

It was observed that the thymus and a certain population of bone marrow lymphocytic cells were repopulated in parallel in a cyclic fashion. This occurred either after a single exposure of mice to 400 R or after serial weekly X‐ray treatments with 170 R. Lethally irradiated recipients which were grafted with bone marrow cells obtained 12‐24 days after four weekly irradiations of donor mice with 170 R also exhibited a cyclic repopulation of both the thymus and the bone marrow lymphocytic population. In contrast, mice which were transplanted with bone marrow cells from unirradiated donors, containing an equal number of stem cells (CFU), exhibited a continuous rather than a cyclic recovery of both cell populations. the bone marrow stem cells of mice recovering from X‐irradiation were found to have a decreased proliferative activity, since they produced significantly smaller spleen colonies in lethally irradiated recipients than marrow cells from unirradiated mice.

The results were interpreted as indicating that the bone marrow lymphocytic cells may act as thymic precursor cells and that thymic lymphopoiesis is dependent on the presence of such cells. Evidently, the production of lymphocytic cells will decrease when the stimulus for granulocyte production increases due to the limited proliferative activity of the surviving bone marrow stem cells after irradiation. This may result in a cyclic variation of the production of bone marrow lymphocytic cells and it follows that thymic lymphopoiesis will run parallel.
COLONY FORMATION IN AGAR: IN VITRO ASSAY FOR HAEMOPOIETIC STEM CELLS
Authors: Dicke K. A. , Platenburg M. G. C. , van Bekkum D. W.
Published: May 2008

Using a method in which embryo fibroblasts were used as feeder layers, the colony forming capacity in agar of a variety of mouse haemopoietic suspensions was compared with their CFUs content. A striking parallelism between the results of the two assays was found. In addition, under certain conditions higher numbers of CFUs could be retrieved from 5‐day‐old agar colonies than were originally plated, indicating that the CFCa (Colony Forming Cell agar) may fulfil the requirements of pluripotency as well as of self‐renewal, both prerequisites for any haemopoietic stem cell candidate. Although our data by no means provide direct proof that the CFCs and the CFCa are identical, they certainly support such a concept. the contradictory findings by others that CFUs and CFUc (Colony Forming Unit culture) can be separated on a velocity gradient is attributed to different culture conditions, in other words, that their CFUcè are not identical with our CFUa.

Our findings also indicate that for mouse cells our soft agar colony assay meets the criteria of a quantitative assay for haemopoietic stem cells and that extension of this technique to bone marrow of primates including humans seems to be justified.
THE LYMPHOCYTES OF CHRONIC LYMPHOCYTIC LEUKEMIA: THEIR PROLIFERATION AND CELL CYCLE KINETICS
Authors: Johnson L. Ione , LoBue Joseph , Rubin Arnold D.
Published: May 2008

Lymphocytes obtained from CLL patients exhibited a delayed and reduced response to PHA when cultured in diffusion chambers. DNA synthesis (8–10 hr) and general time (15–19 hr) of the late‐developing CLL blasts were consistent with normal values (Ts: 8–10 hr; Tc: 14–17 hr). However, the G2 period of CLL blasts seemed more variable, and their mitotic index during the response at 5–6 days was 30–50% of the values determined for normal blasts during their peak response at 2–3 days.
THE LABELLED MITOSES CURVE AND THE ESTIMATION OF THE PARAMETERS OF THE CELL CYCLE
Authors: Gilbert C. W.
Published: May 2008

A method is described for fitting a ‘fraction labelled mitoses’curve to a set of data points and for estimating the values of the best fitting parameters of the cell cycle. Estimates of the SE of the parameters are obtained. The method depends on the fact that when gamma distributions are used to describe the durations of the phases of the cell cycle, the Laplace transform of a FLM curve can be described by simple analytic functions enabling a least squares fit to be made to a set of Laplace transforms of the experimental data. The method is easy to program and quick to execute.
A MONTE CARLO SIMULATION OF CLONE GROWTH
Authors: Szekely Joseph G. , Kennedy Gregory G. , Hoffman Joseph G.
Published: May 2008

A Monte Carlo simulation of clone growth is discussed from the point of view of clonal volume. It is shown that clone volume is a good representation of the number of cells per clone for a wide range of single cell growth equations. However, the rate at which the coefficient of variation in clonal volume approaches that of cell number per clone is strongly dependent upon the particular growth equation.
PROLIFERATION KINETICS IN EPITHELIUM OF GUINEA‐PIG COLON III. DISTRIBUTION OF BLOOD CAPILLARIES ALONG THE CRYPT
Authors: Rowiński J. , Nowak M. , Sawicki W.
Published: May 2008

The colonic blood vessels of the guinea‐pig were infused with carmine‐gelatine and the occurrence along the crypt of mucosal capillaries containing the dye was examined. The pattern of capillary distribution along the crypt is inhomogeneous but is similar for short, medium and long crypts. Capillaries occur least frequently at the bottoms of crypts, that is within the lowest 0.05% of the crypt length. The frequency rises significantly between 0.05 and 0.40 of the crypt length; this rise is accompanied by an increase in the number of DNA‐synthesizing cells. A significant fall in capillary frequency along the crypt between 0.35 and 0.45 of crypt length coincides with the beginning of a decrease in the number of DNA‐synthesizing cells. The highest frequency of capillaries occurs in the upper 0.20 of the crypt length and beneath the lining epithelium.
SELF‐RENEWAL OF COLONY FORMING UNITS (CFU) IN SERIAL BONE MARROW TRANSPLANTATION EXPERIMENTS
Authors: Vos O. , Dolmans M. J. A. S.
Published: May 2008

The capacity of stem cells (CFU) for self‐renewal was tested by transplanting normal bone marrow (primary transplantation) and bone marrow which had been subjected to one or two earlier transplantations (secondary and tertiary transplantation) into lethally irradiated syngeneic recipients. It was found that the capacity for self‐renewal is diminished within the first weeks after one or more previous transplantations. This ability of stem cells recovered after a longer interval after the previous transplantation. The time required for this recovery depended upon the number of previous transplantations and amounted to more than 1 or 2 months after one or two transplantations respectively. Shortly after transplantation the CFU/nucleated cell ratio in bone marrow was below normal and its decrease was more pronounced when the bone marrow had been transplanted more often. An increase of the ratio towards normal values was observed in the course of one month after the last transplantation. Measurements of the spleen colony size after transplantation of normal and re‐transplanted bone marrow indicated that CFUs from re‐transplanted marrow gave slightly smaller spleen colonies than those of normal marrow.

It is concluded that the decreased self‐renewal of stem cells shortly after previous transplantations is probably not due to a limitation in the number of normal mitoses they can perform, but to a loss of stem cells by transfer to the compartment of differentiating cells.
STIMULATION OF HAEMOPOIETIC COLONY FORMATION BY ANTILYMPHOCYTE SERUM
Authors: Chertkov J. L. , Lemeneva Lylian N. , Mendelevitch Olga A. , Udalov G. A.
Published: May 2008

Stimulation of endogenous and exogenous colony formation by antilymphocyte serum has been observed. The effect of ALS on endocolonization is associated with promotion of CFU recirculation. ALS‐induced stimulation of exocolonization was observed only with adult bone marrow cells of normal mice. ALS caused no effect on colony formation induced by embryonic liver cells or rapidly proliferating haemopoietic cells of early radiation chimeras. ALS did not cause an increase either in the content of CFU in the spleen or in their proliferating fraction. It is assumed that the ALS effect is exerted on the microenvironment and not directly on the CFU, as the result of which short‐range regulation of haemopoietic stem cell changes.