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There exists ample evidence that granulopoiesis is an actively controlled process. The observation of cyclical granulopoiesis in chronic granulocytic leukemia (CGL) suggests that control is deranged rather than abolished in this disorder. Analysis of the kinetics of granulopoiesis in CGL may provide some insight into the nature of the derangement. To facilitate analysis, a mathematical model of the granulopoietic control system is proposed and examined using computer simulation. With model parameters initially chosen to represent normal granulopoiesis, the minimal changes necessary to represent granulopoiesis in CGL were investigated. This analysis indicates that two separate changes seem to be required: (1) the granulocyte maturation time must be increased and (2) the precursor input to the granulocytic pathway of development must also be increased. A causal association between delayed maturation and rising precursor input is suggested, and some possible mechanisms of association are proposed.

Objective: The aim of this study was to investigate causal association of serum ferritin with pre-term labour . Materials and Methods: This is a case-control study done on one hundred and twenty women from July 2005 to June 2007 in the department of obstetrics and gynecology of Bangabandhu Sheikh Mujib Medical University (BSMMU) and Mother and Child Health Training Institute (MCHTI), Azimpur, Dhaka. Cases (n=60) were singleton pregnant women starting preterm labour within 28-36 weeks of pregnancy and control (n=60) were singleton pregnant women of >37 weeks of gestation who were in lalour. In this case-control study pre-term labour patients were compared with controls regarding their serum ferritin level. Result: Mean ±SD serum ferritin level of control and in pre-term labour group of women were 37.01±26.84 μg/L was 210.37±67.20 μg/L respectively. The difference between two groups was statistically highly significant (

The descriptive epidemiology of ovarian malignancies, including age, marital status and race, is discussed. A study of 97 cases of ovarian malignancies compared to 97 cases of benign ovarian tumors is analyzed. Between most of the variables there are no statistically significant differences. Three variables, however, are of special importance: (1) history of x-irradiation, (2) history of internalization of hormones and (3) history of mumps parotitis. In the first 2 variables no statistically significant differences were found. The conclusion is that exposure to x-irradiation and the internalization of hormones did not influence the onset of ovarian malignancies. With the third variable a p value of 0.007 was encountered. The difference favored having mumps. The benign controls gave a history of mumps parotitis far more often than did the patients with ovarian malignancies. A causal association with a possible protective value is suggested.

As a result of an electron-microscopic study of the distribution of ‘osmiophilic bodies’ in the lateral geniculate nucleus obtained from sixteen young monkeys the following conclusion are drawn. 1. There are morphologically different types of osmiophilic bodies found in the lateral geniculate nucleus of the monkeys. 2. The term ‘osmiophilic body’ seems to be inadequate and confusing in the midst of numerous light and electron-microscopical studies and it is suggested that it may be replaced by a more specific expression—applicable to only electronmicroscopy i.e. ‘electrondense’ bodies. In such cases it is essential to denote the topographical relations, if the exact source or chemical nature is uncertain. 3. The possible relationship with the mitochondria has been discussed. 4. As osmiophilic bodies within the mitochondria, in the immediate neighbourhood of the blood vessels, and in some of the glia cells have been observed only in the material obtained from the operated animals and not in the normal ‘controls’, a causal association with the pathological alteration is suggested.

The chromosome findings in a series of 173 Down’s syndrome or presumptive Down’s syndrome index patients, and a further 3 5 pairs of parents of Down’s syndrome index cases, are given. One hundred and forty-four index cases had primary G21 trisomy; six were interchange trisomics, six were mosaics, and one was a chromatin positive male with XXY sex chromosomes and primary G21 trisomy. Sixteen index patients whose diagnosis could not be clinically confirmed, were found to have normal chromosomes. The 35 pairs of parents all had normal chromosomes. In seven families (three index patients with primary G21 trisomy, two with normal chromosomes and two index patients not studied) minor morphological chromosome anomalies were observed. The relevance of this data to the causal association of Down’s syndrome and G21 trisomy, the frequency of mosaicism, double trisomy and association with other chromosome anomalies, is discussed.

Data on 6407 consecutive medical patients admitted to hospital have been analyzed to assess the relationship between regular analgesic ingestion and impaired renal function. A history of daily oral analgesic use was given by 461 patients (7.2 per cent). From the data presented we conclude that the frequency of renal damage was not significantly higher among regular analgesic consumers, when compared with occasional analgesic consumers or patients who denied consumption of analgesics. In addition, there was no evidence of a relationship between increasing duration of daily analgesic consumption and renal disease, except in the case of females over age 60 yr, where the presence of white blood cells in the urine was associated with increasing duration of daily analgesic use; this finding may have occurred by chance, however. The data provide no evidence of a causal association between analgesic consumption and the subsequent development of impaired renal function.

Excerpt To the editor: The letter by Dr. Wilde (1), which raises the question of a causal association of phenformin and pancreatitis, prompts me to report a case of pancreatitis in association with...

The background of this book is not stated, although it is relevant to its review. Some 10 years ago the author achieved quantitative, differential separation of low-density serum lipoproteins by adjusting the medium to density 1.06 and photographically recording flotation rates during ultracentrifugation. This brilliant technical development was followed by enthusiastic reports that showed a close association between high concentrations of lipoprotein class S f 12-20 and previous myocardial infarction. Subsequent data extended the correlation to lipoproteins S f 20-400. The data were numerically expressed by weighing factors as an 'Atherogenic Index,' based on lipoprotein distribution and diastolic pressure. As the author Indicates, this term implies a causal association which is not fully established and which is not essential to this presentation, although he adduces evidence to suggest that it may be valid. His concepts are developed calmly, clearly, and persuasively, with only faint gleams of the contentiousness and

Court Brown and Doll (1957) have stressed the causal association between irradiation and leukaemia. Faber (1957) argued that acute leukaemias can be induced by irradiation, with a latent period of five years or less. Stewart, Hewitt and Webb (1956), in a preliminary communication, suggested that diagnostic irradiation in utero, or doses of not more than 5 r to the foetus, may cause leukaemia in post-natal life; Faber (1957) had also concluded that some leukaemias in his series must have been caused by diagnostic irradiation. Court Brown and Doll (1957), and Lewis (1957), accepting that leukaemia is induced in man by ionizing radiations, suggested a non-threshold effect.

To the Editor:— I have read with considerable interest the comments by Dr. Carey P. McCord and Dr. Rutherford T. Johnstone inThe Journalfor Sept. 11, 1954, page 194, on my paper entitled "Aplastic Anemia Following Exposure to Carbon Tetrachloride" (J. A. M. A.155:737 [June 19] 1954). Both of your correspondents raise some question as to the relationship of the carbon tetrachloride and the observed bone marrow damage. I believe they are justified in regarding the causal association as unproved. Indeed, the tentative nature of my conclusions would negate the imputed "diagnostic finality" of the paper. The three cases cited hardly represent a controlled experiment, and confirmation is needed. It is significant that, in the cases reported, the first patient also had severe, overt damage to the liver from which recovery took place and the second patient showed some damage to the liver on postmortem examination. Careful