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EDITOR—Minerva recently drew attention to the World Health Organisation haemoglobin colour scale for near patient determination of haemoglobin concentrations. 12 This apparently elicited response from “a lot of elderly readers” who suggested that it is simply a reinvention of the old Hawksley colour scale. It is, in fact, based on the even earlier “blotting paper” method, which was developed by the …

This document is intended to assist towards the WHO objective that external quality assessment (EQA) schemes be established at national and/or regional levels world-wide. Quality assurance is defined as all steps taken by the director of a laboratory to ensure reliability of laboratory results and to increase accuracy, reproducibility and between-laboratory comparability. This includes the use of internal quality control procedures and participation in external quality assessment. Internal quality control provides the means for evaluation of analytic test results at the time of testing in order to decide whether they are reliable enough to be released to the requesting clinicians. EQA, on the other hand, refers to a system of retrospective and objective comparison of results from different laboratories by means of proficiency testing (PT) organised by an external agency. The main purpose is to establish between-laboratory and between-method (including between-instrument) comparability, and agreement with a reference standard where one exists. Internal quality control and EQA complement each other and must never be considered as alternatives.

Total red cell volumes and splenic red cell pools were measured in 31 patients with polycythaemia. 22 had polycythaemia vera (PV), 12 of whom had clinically detectable splenomegaly, and nine patients had secondary polycythaemia (PS). The mean red cell pool was 192.8 ml (SD 126.6) in PV (all cases), and 130.9 ml (SD 28.4 ml) in PV without splenomegaly; it was 61.1 ml (SD 8.3 ml) in PS. When expressed relative to spleen size (in cm), differences were even more striking: PV (all cases)--mean 13.7 ml/cm (SD 4.3); PV without splenomegaly--mean 12.7 ml/cm (SD 2.2); PS--mean 6.6 ml/cm (SD 1.2). Measurement of splenic red cell pool thus appears to be a valuable diagnostic tool for distinguishing between PV and PS. The findings point to the presence in PV of a splenic structural abnormality which is not simply an effect of the increased circulating red cell mass.

Batch variations in commercial dyes employed for Romanowsky-type staining have been studied by thin-layer chromatography.The colored components of numemus batches of the thiazine dyes azure A, azure B, azure C, methylene blue, methylene violet hthsen, thionine and tduidine blue, and of the xanthene dyes emin B and eosin Y, have been compared. It has been found that of these dyes only methylene blue and thionine are commercially available reasonably free of colored contaminants. The azures, methylene violet Bernthsen and toluidine blue are complex mixtures of thiazine dyes of the thionine and thionoline series. Samples of eosin B are mixtures of the nominal dye with win Y, fluorescein and tribromofluorescein. Thoee of eosin Y are mixtures of this dye with fluorescein and tribromofluorescein.

Contents of the terminal ilea, ceca-proximal colons, and terminal recta were obtained from nine sheep, three of which were fed 100% orchardgrass hay, three of which were fed 60% cracked corn-40% orchardgrass hay, and three of which were fed 80% cracked corn-20% orchardgrass hay. The digestibility of dry matter in the ceca was greatest when the all-hay diet was fed, whereas the percentage of cellulose digestion in the ceca increased with increasing levels of concentrate. For all diets, the total volatile fatty acid concentrations were higher in the ceca than in the other two sites. The cecal pH levels decreased with increased corn levels in the diet. The total microbiol numbers per gram of ileal and cecal contents increased in response to feeding of concentrate; however, across all diets, the ileal counts were 8% or less of the cecal counts. In contrast, the cellulolytic microbial numbers in the ilea were 50% or more of those in the ceca and were highest with the all-hay diet. Both bacterial and end product concentrations in the ceca were equivalent to those occurring in rumina. A total of 16 cellulolytic cultures were isolated and characterized from ileal and cecal contents of animals fed all three diets. Seven gram-negative-rod-shaped organisms were identified as Butyrivibrio fibrisolvens, whose capacity to digest cellulose exceeded that of several rumen strains. The guanine-plus-cytosine content of the DNA of one strain of B. fibrisolvens was 38.8 mol%, compared with the only previously reported value for this species of 41.2 mol%.(ABSTRACT TRUNCATED AT 250 WORDS)

Five experiments were conducted to determine the effects of treating wheat straw (WS) with alkaline (pH 11.5) solutions of hydrogen peroxide (H2O2) on ruminal dry matter disapperance (DMD) in sacco. When WS was neutralized with 6 N phosphoric acid (H3PO4) to recover alkalisoluble hemicellulosic constituents, WS neutralized prior to washing had higher disappearance values at 24 and 36 h (P

This paper outlines some recommendations for the use of SI units in reporting the results of investigations made in hospital laboratories. It is based on a report prepared by a working party of representatives of a number of organisations» which was approved in 1973 by the councils or committees of these organi­ sations. A summary of the main recommendations has already been published (Baron, 1973). In recommending the introduction of SI units for the reporting of results obtained in hospital labora­ tories in the U.K., the working party are following the decisions of the relevant international associa­ tions (IUPAC-IFCC, 1972a and b; ICSH-IFCC­ WAPS, 1972). Laboratories all over the world are, or will be, adopting SI units (Young, 1974). During recent years users of laboratory results (physicians, nurses, pharmacists, etc.) have made the change from the Imperial system of weights and measures to the metric system. In most hospitals the first stage of SI will have already been introduced, namely, stan­ dardisation of symbols for units, and replacement of the equivalent by the mole for monovalent ions where no change in number results (Royal College of Pathologists Working Party, 1970).

Summary. We have measured the numbers of myeloid progenitor cells in the circulation of patients with myelofibrosis (MF) and other myeloproliferative disorders. In general, progenitor cell numbers were increased in the circulation of patients with MF compared with controls. The mean increases were 9-fold for the multilineage progenitor cells (CFU-GEMM), 13-fold for the erythroid progenitor cells (BFU-E), 37-fold for the granulocyte-macrophage progenitor cells (CFU-GM) and 167-fold for the megakaryocyte progenitors (CFU-MK). Splenectomized patients generally had reduced numbers of circulating progenitor cells. In the CFU-MK assay, mature megakaryocytes cultured from patients with MF regularly showed large vacuoles in the nucleus and cytoplasm, unlike control cells. The increased colony formation in patients with MK, involving especially CFU-MK colonies, is consistent with the hypothesis that MF is a primary myeloproliferative disorder in which a megakaryocyte-derived factor predisposes to the formation of marrow fibrosis.

In vitro methods for standardising and assessing the reproducibility of reticuloendothelial function tests in man were performed. Variation in the degree of heat-induced red blood cell damage could be detected by both Channelyzer plots and a filtration test of red cell plasticity although the former test was less sensitive and difficult to quantitate. In a consecutive study of the clearance of heat-damaged red blood cells (HDRBC) in 8 patients and 2 normal individuals, consistent changes were demonstrated by both assays although occasionally one assay alone provided inconclusive results. When undamaged red cells were coated with IgG anti-D antibodies, the number of IgG molecules bound per red cell was determined by an indirect antiglobulin radioimmunoassay. With this assay, it was shown that the rate of clearance of coated cells was related to the amount of cell bound IgG anti-D. Some variation in the degree of coating of cells from patients with systemic lupus erythematosus was found although the differences were insufficient to account for the reported reduction in the clearance of IgG-coated cells in patients with this disease. The radioimmunoassay and microhaemagglutination techniques revealed that neither IgG, Clq, C3 or C3d were bound to HDRBC following incubation in autologous serum suggesting that these cells were cleared in vivo by mechanisms unrelated to immune receptor recognition.

A simple, rapid and inexpensive assay method for the colored components of commercial samples of eosin is described. Samples are dissolved in dilute aqueous ammonia and absorbance measurements made at wavelengths of 492 nm, 512 nm, and 518 nm. The concentrations of fluorescein, tribomofluorescein and eosin are derived by solution of simulataneous equations in three unknowns. The validity of the method has been confirmed by recovery experiments. Mean recoveries of fluorescein, tribromofluorescein and eosin were 99.1%, 100.2% and 98.8% respectively. Seventeen commercial samples have been assayed by this procedure. Concentrations of fluorescein, tribromofluorescein and eosin ranged from 0.00%-0.82%, 4.34%-29.92% and 44.89%-82.82% respectively. The sodium concentrations of the same samples were measured by atomic absorption spectrophotometry and found to range from 0.10% to 6.13%. The presence of free halide (Br-, Cl-, or both) was demonstrated. These observations, together with color variations in the samples, indicate that in commercial products eosin is in the form of both the free acid and sodium salt. Volatile matter accounted for 1.68%-16.11% of the samples.

The washout of an insoluble tracer from the lung may be represented by a model with two ventilatory compartments representing poorly and better-ventilated regions. Using boli of a second insoluble gas delivered at a given point during inspirations of a multibreath washout test, the proportions of labeled inspired ventilation reaching the poorly and well-ventilated regions may be determined by analyzing the kinetics of the exhaled tracer. We studied eight normal subjects breathing through large-bore solenoid valves controlled to maintain tidal volume at 600 or 900 ml. Boli consisting of 15 ml of 80% He-20% O2 were delivered over 75 ms; this labeled approximately 125 ml of inspired gas. Boli were delivered after 50 ml had been inspired to mark early inspiration and after 300 ml had been inspired to mark midinspiration. Using 900-ml tidal breaths, late inspiration was marked by boli delivered at 600 ml. Subjects were studied in the seated and the supine positions. In both positions, significantly more of the early breath went to the poorly ventilated compartment. Several possible physiological mechanisms, singly or in combination, could account for these observations, but differences in dead space path length are most likely involved.

We describe a new technique for recovering continuous distributions of ventilation (V) as a function of tidal ventilation/volume ratio (V/V0) from the nitrogen washout. The analysis yields a continuous distribution of V as a function of V/V0 represented as fractional ventilations of 50 compartments plus dead space. The procedure was verified by recovering known distributions from data to which noise had been added. Using an apparatus to control the subject's tidal volume and FRC, mixed expired N2 data gave the following results: a) the distributions of young, normal subjects were narrow and unimodal with a mean ln standard deviation of 0.56 plus or minus 0.13; b) those of subjects over age 40 were broader (ln SD 0.86 plus or minus 0.19) with more poorly ventilated units; c) patients with pulmonary disease of all descriptions showed enlarged dead space; d) patients with cystic fibrosis showed multimodal distributions with the bulk of the ventilation going to overventilated units; and e) patients with obstructive lung diseases fell into several classes, three of which are illustrated. These results suggest that our approach is well suited for clinical investigation.

Bone marrow preparations were examined from 80 patients with aplastic anaemia. The degree of cellularity varied greatly and in a third of the cases it was normal or even hypercellular at one site of aspiration. In the severely hypoplastic marrows lymphoid cells were predominant and this situation was associated with a worse prognosis. There was no correlation between marrow lymphoid cell content and blood lymphocyte count but there was an inverse relationship between blood lymphocyte count and marrow erythroblasts and a close direct relationship between the blood neutrophil count and marrow myeloid cell content. In all cases a proportion of the erythroblasts showed morphological abnormalities. These included especially megaloblastic changes and asynchrony of nuclear-cytoplasmic maturation. There were also binucleated cells, internuclear chromatin bridges, intercellular cytoplasmic connexions, nuclear degenerative changes, namely, blurred outlines, irregular shapes, budding and fragmentation, and atypical mitotic figures. These appearances illustrate the extent to which a qualitative defect of erythropoiesis occurs as part of the haematological pattern in aplastic anaemia, and in some cases dominates the bone marrow picture. Similar cytological features were found in all cases, including five patients with Fanconi's anaemia.

A study of splenic function in 28 patients with adult coeliac disease showed no significant correlation between the half life of heat-damaged red cells and either the duration of pre-treatment exposure to gluten or the length of time on a gluten free diet. A significant correlation was found between splenic size and duration of treatment; those patients who had been taking a gluten free diet for the longest time had the smallest spleens. Blood films from 11 of these 28 patients taken before treatment with a gluten free diet were compared with those taken between two and 15 years after the start of treatment. There was no tendency for the hyposplenic changes to regress. In the majority, the changes became more prominent despite strict adherence to the gluten free diet. These findings suggest that splenic atrophy in adult coeliac disease is not reversed by treatment with a gluten free diet and is unlikely to be related to the state of the jejunal mucosa or the duration of initial exposure to gluten.

Using the lipophilic chelating agent, acetylacetone, red cells have been radiolabelled with the short-lived, generator-produced isotope, 113mIn. Following re-injection of these labelled cells, red cell volume has been measured and compared with corresponding values using 99mTc labelled red cells in 18 patients, and with 51Cr labelled red cells in five patients. 99mTc slightly overestimated red cell volume in relation to 113mIn, but 51Cr values were identical to 113mIn values. There was a close correlation between splenic red cell pool measured with 99mTc and with 113In. It was concluded that the intracellular stability and gamma emission of 113mIn make this isotope a superior alternative to 99mTc and 51Cr in measurements of red cell volume and splenic red cell pool.

The results have been compared of microbiological and radioisotope dilution (RID) assay of serum vitamin B12 by participants in national interlaboratory trials in Britain. There was wide variation between the individual participants, especially marked in the L. leichmannii microbiological assay and in the RID methods, whereas excellent correlation, reproducibility, and recovery were obtained in reference laboratories by microbiological assay with both E. gracilis and L. leichmannii. In general, RID gave higher results than microbiological assay. The need for suitable reference sera is emphasised.

SummaryMean platelet volume was related to platelet count in patients with myocardial infarction (n = 55) and patients with congestive heart failure (n = 9). 18 patients with acute myocardial infarction were tested at admission and 4-7 days later, together with 13 patients with chronic stable angina and 10 patients with chest pain which was not related to coronary artery disease. In citrated blood a relative reduced frequency of large platelets (>13 fl) occured in patients with acute myocardial infarction at admission but was not seen during recovery or in patients with chronic stable angina. This suggests consumption of large platelets at time of thrombus formation. No relation was found between plasma catecholamine levels and mean platelet volumes. Effects of serotonine, adrenaline and CGP 28392, a calcium agonist, on platelet volume distributions were determined. Sensitivity of platelets to adrenaline was increased in patients with acute myocardial infarction on admission and reduced 4-7 days later, while in patients with congestive heart failure reactivity to both serotonine and adrenaline were reduced. This indicates a fast down-regulation during the early recovery phase of myocardial infarction and chronically in congestive heart failure.

A comparison has been made between reticulocyte preparations stained with purified azure B and with several commerically available batches of brilliant cresyl blue and new methylene blue. Marked variations were observed in the composition and staining performances of the various batches of the two commerically available dyes. Although there were no significant differences in reticulocyte counts obtained with these two dyes, varying amounts of an extraneous, particulate dye deposit were present in these preparations, making accuracte counting both tedious and timeconsuming. Purified azure B, on the other hand, gave reproducibly stained, deposit-free preparations. Reticulocyte counts obtained from azure B preparations correlated almost exactly with those determined using new methylene blue. Purified azure B is therefore recommended as a convenient reticulocyte stain for routine use.

Detailed schemes are described for the preparation of purified methylene blue and azure B from commercial samples of methylene blue. Purified methylene blue is obtained by extracting a solution of the commercial product in an aqueous buffer (pH 9.5) with carbon tetrachloride. Methylene blue remains in the aqueous layer but contaminating dyes pass into the carbon tetrachloride. Metal salt contaminants are removed when the dye is crystallized by the addition of hydrochloric acid at a final concentration of 0.25 N. Purified azure B is obtained by extracting a solution of commercial methylene blue in dilute aqueous sodium hydroxide (pH 11-11.5) with carbon tetrachloride. In this pH range, methylene blue is unstable and yields azure B. The latter passes into the carbon tetrachloride layer as it is formed. Metal salt contaminants remain in the aqueous layer. A concentrated solution oa azure B is obtained by extracting the carbon tetrachloride layer with 4.5 X 10(-4)N hydrobromic acid. The dye is then crystallized by increasing the hydrobromic acid concentration to 0.23 N. Thin-layer chromatography of the purified dyes shows that contamination with related thiazine dyes is absent or negligible. Ash analyses reveal that metal salt contamination is also negligible (sulphated ash less than 0.2%).

The ultrastructure of the cellular interfaces between erythroid precursors has been studied in both congenital and acquired dyserythropoiesis. The types of cell-to-cell contacts found included highly convoluated interdigitating septate-like junctions as well as apparent confluence of the cellular membranes of adjacent erythroid cells. Such findings are not characteristic of the intercellular relationships found in the normal erythroblastic islands. The erythroid plasma membrane modifications are possibly related to the changes in the plasma membranes of erythroid cells known to occur in dyserythropoiesis and their presence may well contribute to the ineffective erythropoiesis with intramedullary cell destruction which characterizes many dyserythropoietic states.

Summary. Measurements of integrated optical density and projected area of red cells have been made on Romanowsky-stained blood films from 25 subjects using an image analysing computer. Close correlation was observed between mean cell projected area and MCV and between mean cell integrated optical density and MCH. Mean values for the quotient of cell integrated density/cell projected area (mean cell colour density) correlated with MCHC. Variances of cell area and colour density correlated subjectively with anisocytosis and anisochromasia, and histograms of these parameters demonstrated dual populations. The clinical application of these findings is discussed.

Electron microscopy of erythropoiesis in aplastic anaemia has demonstrated some unique features of dyserythropoiesis at the ultrastructural level, which contribute to understanding of the morphological features which are seen in the light microscope. The findings provide further evidence for the presence of qualitative defects in erythropoiesis in aplastic conditions. The alterations seen included bi- and multinucleated cells, intercellular bridges containing microtubules, internuclear chromatin bridges, irregular nuclear shapes, juxta-nuclear and peripheral cisternal structures, ringed sideroblasts, a diversity of intranuclear inclusions, nuclear clefts in both eu- and heterochromatin, and a variety of anomalies of the nuclear membrane. The significance of the occurrence of these anomalies in aplastic anaemia is considered and the role of the nuclear membrane and of endoplasmic reticulum in the pathogenesis of aplastic anaemia is discussed.

Summary. The effects of various treatments on erythrocyte shape, surface, cell coat and calcium binding sites have been investigated by means of high voltage electron microscopy (HVM), scanning electron microscopy (SEM) and conventional electron microscopy (TEM). Papain caused the formation of small blisters within the cellular surface as well as crenation and‘budding’of the erythrocytes. Afer neuraminidase treatment, long filaments were observed to radiate from the surface of the erythrocyte. The other enzymes investigated, RNAse, DNAse, phospholipase, protease and trypsin, produced no demonstrable effect on the cellular structure, nor (with the possible exceptionof trypsin) on the cell coat as seen by subsequent staining with ruthenium red. Putative calcium binding sites on and in the erythrocyte membrane were demonstrated. Following incubation with radioactive calcium, activity was found in the erythrocyte membranes. Calcium binding could be reduced by prior treatment of the erythrocyte with EDTA, neuraminidase, and to a lesser extent, by papain and trypsin. Other enzymes had no demonstrable effect. Stored erythrocytes showed a progressive diminution in calcium binding over a period of up to 4 weeks.

SummaryIn 1983, the World Health Organization (WHO) published recommendations for normalization, in oral anticoagulant control, of the prothrombin time (PT). The common denominator is the International Sensitivity Index (ISI) of a thromboplastin, obtained by means of thromboplastin calibration. The common scale is that of the International Normalized Ratio (INR). The INR is the PT ratio Patient PT/normal PT which would have been found normal PT with the WHO primary international reference preparation (IRP) 67/40. The reliability of the INR depends on the extent of calibration precision, patient-specific influences, as well as interlaboratory variation in the PT determination. Under well-controlled conditions the overall coefficient of variation (CV) of the INR is 11-13.5%, if thromboplastins of ISI ≃ 1 are used. For so-called low-sensitivity thromboplastins (ISI ≃ 2-2.5), the overall variation is larger due to a large between-laboratory variation of the measured PT-ratiosThe user of thromboplastin will be provided with a chart or graph enabling him to convert the conventional terms used for expressing PTs into INRs. For quality assurance, and to prepare his own calibration chart if necessary, he should check normalization by means of control plasmas to which INRs have been assigned.There is sufficient clinical evidence to express optimal therapeutic ranges in terms of INR. Manufacturers should revise and adapt their inserts where necessary in order to conform to these requirements.

In classical gambler's ruin against an infinitely rich adversary the difference equation for the probability of ruin has no unique solution when the odds are in the gambler's favour. A more general problem is considered and a solution proposed which avoids both the use of generating functions and the usual device of considering the limit from the finite case. A link with the theory of branching processes is indicated.

The stability of the commonly used red cell radio labels chromium-51, indium-(111 or 113m), and technetium-99m, within intact red cells and stroma and their distribution within the cell were compared in undamaged and heat damaged red cells in relation to the clinical use of heat damaged cells in the assessment of splenic function. Chromium-51 labelled haemoglobin both in undamaged and heat damaged cells; indium predominantly labelled haemoglobin in undamaged cells but labelled stroma in heat damaged cells, even when the cells were labelled before heating; technetium-99m predominantly labelled haemoglobin in undamaged cells but only labelled stroma in heat damaged cells if these were heated before labelling. Indium was more firmly bound by stroma prepared from heat damaged cells, and technetium-99m showed a high rate of elution both from cells and stroma, although this rate was lower for heat damaged cells.

Summary. A method has been developed by means of which independent measurement can be made of the amount of red-cell destruction occurring in the spleen and the liver. The technique involves a standard red-cell survival study and surface-counting measurements together with quantitative scanning of the spleen and liver with 113mIn colloid in order to calibrate the surface counter. The rate of destruction in each organ is obtained by fitting the measured uptake curve for the organ to a theoretical uptake curve by computer. In addition, if whole body counting is also performed, the amount of red-cell destruction occurring in the rest of the reticulo-endothelial system may be deduced. Results are given for measurements on a series of 11 patients.

Finally, it must not be forgotten that the DLC is only one aspect of examination of the blood film. Morphological abnormalities of the erythrocytes or platelets, rouleaux, cryoglobulin deposits, even an unexpected finding of malaria parasites might point to the diagnosis and help solve an otherwise obscure problem. Indeed, perhaps the greatest value of performing a manual DLC is that it ensures that the blood film has been examined adequately to reveal morphological anomalies. It would be a retrograde step if automated procedures resulted in abandonment of blod film screening. Thus, whatever the future of the DLC and its automation, microscopic examination of the blood film by a qualified haematologist should remain as the basis of good haematological practice.

The effects of sodium hydroxide (NaOH) and alkaline hydrogen peroxide (AHP) treatments on wheat straw (WS) and various cellulosic substrates were determined by measuring susceptibility to degradation by mixed ruminal organisms or Bacteroides succinogenes S85. In vitro incubations were used to measure differences in fermentation resulting from each successive step in the AHP treatment process. In vitro incubations through 48 or 108 h were conducted to measure these differences. The AHP treatment of WS increased (P less than 0.05) dry matter, neutral detergent fiber, and acid detergent fiber degradation over control WS when these substrates were incubated with mixed ruminal microorganisms or B. succinogenes S85. Fermentations containing AHP-treated WS had greater (P less than 0.05) microbial purine (RNA) and volatile fatty acid concentrations by 12 h compared with those containing untreated or NaOH-treated WS. Xylose in AHP-treated WS was utilized more extensively (P less than 0.05) by 12 h compared with the xylose of untreated or NaOH-treated WS. Treatment with AHP removed 23% of the alkali-labile phenolic compounds from WS. When substrates with high levels of crystalline cellulose (raw cotton fiber, Solka floc, and Sigmacell-50) were treated with NaOH or AHP and incubated for 108 h with B. succinogenes S85, extent of acid detergent fiber degradation of cotton fiber and Sigmacell-50 was similar to that of their respective controls. Sodium hydroxide and AHP treatments were effective in increasing acid detergent fiber degradation of the Solka floc which contained, on average, 3.3 and 4.8 percentage units more acid detergent lignin and hemicellulose, respectively, than cotton fiber and Sigmacell-50.(ABSTRACT TRUNCATED AT 250 WORDS)

Total red cell volume (TRCV) and plasma volume (PV) have been measured in 130 cases including 65 polycythaemic patients and 65 patients with a wide variety of disorders. Patients with gross splenomegaly were excluded from the study. The regression of TRCV on venous haematocrit (VHct) was found to be curvilinear, a single exponential function providing a good approximation ( r=0.92, P less than 0.001). No significant difference was found between the mean PVs of the polycythaemic and control groups (40.97 and 42.94 ml/kg respectively) although a slight but highly significant negative correlation was observed between PV and VHct (r = 0.47, P less than 0.001). This most marked for patients with VHcts below 0.30, for whom a separate plot yielded a correlation coefficient of 0.75. Total blood volume (TBV) and VHct were found to be positively correlated (r = 0.57, P less than 0.001) as would be expected from the TRCV and PV data. The significance of these findings is discussed.

A convenient, rapid and extremely effective thin-layer chromatographic system for the analysis of Romanowsky-type blood stains is reported. The system employs silica ad absorbent, and as developing solvent, the butanol layer obtained from butan-1-al (12 vol), 1% w/v aqueous ammonium chloride (5 vol) and 2% v/v aqueous formic acid (2 vol).The separations obtained are illustrated using a commercial sample of each of the following stains: azure A (CI 52005), azure B (CI 52010), azure C (CI 52002), methylene blue (CI 52015), methylene violet Fkrnthsen, eosin bluish (CI 454500), eosin Y (CI 45380), Giemsa stain, Jenner stain, Leishman stain, MayCrunwald stain, Romanowsky stain, Wright stain.

Recent studies suggest pH sampled by arterial chemoreceptors may not equal that sampled by external pH electrodes, because the uncatalyzed hydration of CO2 in plasma is a slow reaction (t 1/2 approximately 9 S). The importance of this reaction rate to ventilatory control (particularly during exercise) is not known. We studied the effect of catalyzing the CO2-pH reaction in three awake exercising dogs with chronic tracheostomies and carotid loops; the dogs were trained to run on a treadmill. Respiration frequency, tidal volume, total ventilation, and end-tidal partial pressure of CO2 (PCO2) were continuously monitored. Periodically, carotid artery blood was drawn and analyzed for partial pressure of O2 (PO2), PCO2, pH, and plasma carbonic anhydrase (CA) activity. Measurements were made during steady-state exercise (3 mph and 10% grade), during a control period, after injection of a 5 ml bolus of saline, and after injection of 5 mg/kg of bovine CA dissolved in 5 ml of saline. This dose of CA increased the reaction rate by more than 80-fold. Neither the control nor the CA injections significantly altered the ventilatory parameters. Saline and CA date differed by less than 5% in ventilation, 1 Torr in arterial PCO2, 0.01 in pH units, and 1.5 Torr in end-tidal PCO2. Thus the of CO2 hydration in plasma is not a significant factor in ventilatory control.

Summary. Eleven patients have been observed with clinical features of both polycythaemia vera and myelofibrosis. Detailed follow-up and repeated haematological and isotopic investigations, including the assessment of erythropoietic distribution by 52Fe scanning, over a 10 year period, have indicated that patients who initially present with this syndrome may remain in a steady state for several years and that this transitional syndrome does not necessarily imply an active or irreversible transformation into classical myelofibrosis. Therapy with iron, folic acid, alkylating agents, splenectomy or splenic irradiation may reduce the extramedullary component of myeloproliferation and allow occasional patients to revert to more classical polycythaemia vera. Radioactive phosphorus (32P) therapy may be inappropriate in polycythaemic patients with dominant extramedullary erythropoiesis, as this form of therapy has a preferential medullary action and may selectively encourage extramedullary myeloproliferation.

An interlaboratory trial of the quantitation of Hb A(2) and Hb F has been carried out on two samples of blood by 90 laboratories in the British Isles. The results have been compared with those obtained by four reference laboratories. Overall, the correlation was very poor and indicated that the methods used have to be standardized before interlaboratory values become meaningful. Moreover, in many laboratories the level of Hb A(2) in a patient with proven beta thalassaemia was not reported as being increased.

A method is described for converting the data obtained by external counting after administration of 51Cr-labelled red cells into a quantitative measurement of splenic sequestration. This involves the administration at a later stage of a second sample of red cells, which are double labelled with 81Rb and 51Cr and are damaged in vitro with l-mercuri-2-hydroxypropane to ensure their preferential uptake by the spleen. By means of a scan of the 81Rb activity the fractional uptake of the in vitro-damaged cells by the spleen can be measured, and then related to the external count. This permits the sequestration by the spleen of 51Cr-labelled natural cells to be estimated quantitatively. This provides a more reliable measurement than external counting alone in evaluating the role of the spleen in haemolytic anaemias and the indications for splenectomy. The reasons for selecting 81Rb and the theoretical considerations are presented. The method has been applied in a study on a patient suffering from heredi...

Bei 36 Patienten mit bioptisch gesicherter Myelo- und Osteomyelosklerose wurden Blutvolumen, Gesamtmenge zirkulierender Erythrocyten und Erythrocytenlebensdauer mittels51Cr markierten Erythrocyten bestimmt. Obwohl 30 der 36 Patienten einen erniedrigten peripheren Hamatokrit zeigten, war die gesamte Erythrocytenmenge nur in einem Siebentel der Patienten signifikant vermindert. Als Ursache dafur konnte erstens eine Verdunnungsanamie durch ein erhohtes Blutvolumen nachgewiesen werden, das zur Grose der Milz in Beziehung stand. Zweitens fand sich eine relative Vermehrung der gesamten Erythrocytenmenge, die beim Vergleich mit einer Kontrollgruppe von 125 Personen ohne Milztumor uber einen weiten Hamatokritbereich deutlich war und uber einen reinen Verdunnungseffekt hinausging. Die Patienten mit hochgradiger Splenomegalie hatten zur Erreichung eines bestimmten Hamatokrites eine etwa doppelt so grose Erythrocytenmenge notwendig als die Vergleichsgruppe ohne Milztumor.

For spleen scanning there may be advantages in damaging red cells with non-radioactive 1-mercuri-2-hydroxypropane (MHP) and labelling them with a short-lived isotope which emits medium energy γ rays. This is especially so if quantitative measurement of red-cell destruction in the spleen is to be attempted. 81Rb has been proposed as an isotope of choice for this purpose. Factors which influence the uptake of rubidium by red cells have been studied; it has been found that it is mainly dependent on the concentration of ionic Rb+ and only to a minor extent on the volume of red cells in the incubation mixture. 81Rb, together with non-radioactive Rb+ in a concentration of about 5 mM 1−1 gives maximum labelling efficiency. A technique has been developed which ensures that blood can be labelled with 81Rb with an efficiency of 15 per cent per ml. of red cells. This is sufficient to produce a satisfactory spleen scan, and results in a radiation dose to the spleen of 16·5 mrads per μCi injected. This is con...

Radiotherapy may be used in myelosclerosis in order to reduce the massive splenomegaly. The effect of splenic irradiation on two aspects of splenic function was studied in three patients with myelosclerosis. 52Fe, the short-lived isotope of iron, was used for the assessment of erythropoiesis, and 99Tcm sulphur colloids were used for the assessment of phagocytic activity of the reticulo-endothelial cells of the organ. All patients showed extra-medullary erythropoiesis in the spleen. This was abolished within the treated area although the overall dose, time and fractionation regime varied. However, the same areas were still able to concentrate 99Tcm sulphur colloids. Thus radiotherapy of the spleen in myelosclerosis results in a situation where colloid scanning fails to correlate with functioning haemopoietic tissue; the phagocytic function is more radioresistant than the erythropoietic one. The implications of these findings are considered and some aspects of erythrokinetics in myelosclerosis, esp...