Instantons and the Path to Intermittency in Turbulent Flows

Processes leading to anomalous fluctuations in turbulent flows, referred to as intermittency, are still challenging. We consider cascade trajectories through scales as realizations of a stochastic Langevin process for which multiplicative noise is an intrinsic feature of the turbulent state. The trajectories are conditioned on their entropy exchange. Such selected trajectories concentrate around an optimal path, called instanton, which is the minimum of an effective action. The action is derived from the Langevin equation, estimated from measured data. In particular instantons with negative entropy pinpoint the trajectories responsible for the emergence of non-Gaussian statistics at small scales.

A 1,2,3-triazolate lithium salt with ionic liquid properties at room temperature

A triethylene glycol-based 1,2,3-triazolate lithium salt with ionic liquid properties at room temperature is synthesized in three steps including copper-catalysed cycloaddition between alkyne-functionalized monomethoxy-triethylene glycol and azidomethyl pivalate, followed by the deprotection of the methyl pivalate group and further lithiation of the 1H-1,2,3-triazole intermediate.

Hybrid supercapacitor-battery materials for fast electrochemical charge storage

High energy and high power electrochemical energy storage devices rely on different fundamental working principles--bulk vs. surface ion diffusion and electron conduction. Meeting both characteristics within a single or a pair of materials has been under intense investigations yet, severely hindered by intrinsic materials limitations. Here, we provide a solution to this issue and present an approach to design high energy and high power battery electrodes by hybridizing a nitroxide-polymer redox supercapacitor (PTMA) with a Li-ion battery material (LiFePO4). The PTMA constituent dominates the hybrid battery charge process and postpones the LiFePO4 voltage rise by virtue of its ultra-fast electrochemical response and higher working potential. We detail on a unique sequential charging mechanism in the hybrid electrode: PTMA undergoes oxidation to form high-potential redox species, which subsequently relax and charge the LiFePO4 by an internal charge transfer process. A rate capability equivalent to full battery recharge in less than 5 minutes is demonstrated. As a result of hybrid's components synergy, enhanced power and energy density as well as superior cycling stability are obtained, otherwise difficult to achieve from separate constituents.

Metallic film optimization in a surface plasmon resonance biosensor by the extended Rouard method

The extended Rouard method is applied to the computation of a multi-absorbing-layer system for the optimization of surface plasmon resonance (SPR) sensors. Specifically, the effect of the properties of a metallic layer on the shape of the reflectivity and sensitivity curve is demonstrated in the case of a Kretschmann configuration. This theoretical investigation allows us to establish the best optical properties of the metal to obtain a localized SPR, given the illuminating beam properties. Toward the development of a sensitive biosensor based on SPR, we quantify the changes in reflectivity of such an optical biosensor induced by the deposition of a nanometric biochemical film as a function of the metal film characteristics and the illumination operating conditions. The sensitivity of the system emphasizes the potential of such biophotonic technology using metallic multilayer configurations, especially with envisioned metamaterials.

Encasement of bedding does not improve asthma in atopic adult asthmatics

AIM

We evaluated the impact of impermeable bed covers on asthma in asthmatics with clinically relevant house dust mite (HDM) sensitization.

METHODS

The study included 32 HDM-sensitized asthmatics in whom HDM allergy was considered as a significant factor in their asthma. They were randomized into either an intervention group whose bedding was encased with impermeable covers, or a control group who received cotton covers. Before and 3 and 6 months after encasement, dust samples were collected from the bedding and assayed for Der p 1. Clinical outcomes included quality of life, lung function, bronchial reactivity to methacholine, symptoms, medications and peak flow rates.

RESULTS

Baseline Der p 1 levels in both the active and the placebo groups were comparable and high (19.2 vs 18.9 microg/g of dust). There was a significant reduction in Der p 1 levels in the active group after 6 months, but not in the placebo group (7.3 vs 21.9 microg/g of dust). Quality of life improved significantly in both the intervention and control groups, but there was no significant difference in the improvements between the groups. There was no significant change in lung function, symptoms, and requirements for medications.

CONCLUSIONS

Encasement of bedding significantly reduced the Der p 1 levels. However, this was not sufficient to produce worthwhile clinical improvement in those in whom dust mite avoidance might well have been recommended as part of their clinical management.

Heat stress, cytokines, and the immune response to exercise

To examine the effect of exercise and heat stress on cytokine production, seven males (77 +/- 2 kg; VO(2peak) = 4.7 +/- 0.4 L min(-1)) completed two (15 degrees C; CON or 35 degrees C; HEAT) 90 min cycling trials at 70% VO(2peak). Blood samples were collected throughout and analysed for spontaneous, and LPS-stimulated intracellular monocyte cytokine production, plasma cytokine levels, and circulating stress hormone concentration. Plasma epinephrine, norepinephrine, and cortisol concentration were elevated (P < .05) as a result of exercise in CON. HEAT increased (P < .05) epinephrine and norepinephrine levels, however, cortisol concentration was not different between the two trials. Exercise had no effect on the concentration of circulating monocytes spontaneously producing IL-6, TNF-alpha or IL-1alpha, however, there was a decrease in the amount of TNF-alpha per cell post-compared with pre-exercise. HEAT had no effect on spontaneous intracellular cytokine production. Circulating levels of both IL-6 and TNF-alpha were elevated in HEAT, but not in CON. Upon stimulation with LPS, the concentration of monocytes positive for IL-6, TNF-alpha, and IL-1alpha production was elevated (P < .01) post- and 2 h post-compared with pre-exercise. Stimulated cells, however, produced less (P < .05) TNF-alpha post-exercise and less (P < .05) TNF-alpha and IL-6 2 h post-exercise. HEAT resulted in an increase (P < .05) in the concentration of stimulated cells positive for TNF-alpha and IL-1alpha, however, did not affect the amount of cytokine produced by stimulated monocytes. These results demonstrate that exercise decreases the amount of cytokine produced by LPS-stimulated monocytes, possibly due to elevated levels of circulating stress hormones. Heat stress did not, however, augment the suppression in the amount of cytokine produced by circulating monocytes upon stimulation, despite elevated catecholamines.

[Dosimetric validation of compensator for their use in clinical routine, in conformation radiotherapy]

PURPOSE

The aim of this work was to establish the acquisition, calculation and 3D compensator manufacturing optimum parameters. This methodology is based on virtual simulation and 3D dosimetry.

MATERIALS AND METHODS

The material used is a helicoidal CT (PQ 5000-Marconi), a virtual simulation system (AcQsim version 4-Marconi), a Treatment Planning System (Dosigray), a linear accelerator Saturne 43 (Varian, CGR), an automated milling system for compensator filters (Autimo 2.5 D-HEK), a water tank phantom (wellhofer) and an homogeneous phantom with simple patterns in order to simulate the obliquity surface of patient body. The compensator was composed by granulate tin because this material ensures a good profile modulation. The compensation plane has been calculated at 80% to dose profile. The compensator thickness profile has been calculated with different acquisition (slice thickness, pitch factor), calculation (attenuation coefficient, bixel) and fabrication parameters (drill diameter, specification of milling system).

RESULTS

After this preliminary study, we have defined the optimum parameters for the compensator realization. We have observed that the slice thickness, bixel size and drill diameter are the parameters that mainly affect the profiles homogeneity. The choice of parameters with smaller dimensions S = 3 mm; B = 3 mm, F = 3 mm, improve the profiles homogeneity. Though, for manufacture times compatible with the clinical routine, the selected parameters are S = 5 mm, B = 6 mm and F = 6 mm. Compensator can be used for any type of Linac. However, one must pay attention on their realization and their positioning on the beam central axis.

Mouldy houses influence symptoms of asthma among atopic individuals

BACKGROUND

The influence of current levels of indoor fungi on asthma is a controversial issue that needs to be resolved in order to advise patients appropriately.

OBJECTIVE

To assess the seasonal variation in indoor fungal levels and the impact of these levels on asthma among mould-sensitized individuals.

METHODS

Thirty-five young adults with current asthma and sensitization to fungi were visited four times over 1 year. At each home visit a questionnaire was administered and samples of dust and air were collected. Participants also recorded information on symptoms, peak expiratory flows (PEF) and medication use. Dust samples were analysed for house dust mite allergen (Der p 1) and total fungal biomass (ergosterol). Total and genus-specific fungal propagules were identified in air samples. Seasonal variation in allergen levels and significant independent effects of fungal levels on peak flow variability (PFV) were identified by repeated measures analysis of variance.

RESULTS

Significant seasonal variations were observed in viable airborne fungi, ergosterol levels in the floor dust and PFV. PFV correlated significantly with symptom scores and the dose of reliever medication. PFV was also significantly associated with smoking and visible mould. The association between visible mould and PFV was independent of season, smoking and the dose of reliever medication. However, there was no association between total fungi, specific fungi or ergosterol and PFV. Der p 1 levels had no significant influence on asthma, even in HDM-sensitized individuals.

CONCLUSIONS

Mouldy homes adversely influence asthma in asthmatics sensitized to fungi.

Effect of adrenergic blockade on lymphocyte cytokine production at rest and during exercise

To examine the effect of exercise and adrenergic blockade on lymphocyte cytokine production, six men ingested either a placebo (control) or an alpha- (prazosin hydrochloride) and beta-adrenoceptor antagonist (timolol malate) capsule (blockade, or BLK) 2 h before performing 19 +/- 1 min of supine bicycle exercise at 78 +/- 3% peak pulmonary uptake. Blood was collected before and after exercise, stimulated with phorbol 12-myristate 13-acetate and ionomycin, and surface stained for T (CD3(+)) and natural killer [NK (CD3(-)CD56(+))] lymphocyte surface antigens. Cells were permeabilized, stained for the intracellular cytokines interleukin (IL)-2 and interferon (IFN)-gamma, and analyzed using flow cytometry. BLK had no effect on the resting concentration of stimulated cytokine-positive T and NK lymphocytes or the amount of cytokine they were producing. Exercise resulted in an increase (P < 0.05) in the concentration of stimulated T and NK lymphocytes producing cytokines in the circulation, but these cells produced less (P < 0.05) cytokine post- compared with preexercise. BLK attenuated (P < 0.05) the elevation in the concentration of lymphocytes producing cytokines during exercise; however, BLK did not affect the amount of IL-2 and IFN-gamma produced. These results suggest that adrenergic stimulation contributes to the exercise-induced increase in the concentration of lymphocytes in the circulation; however, it does not appear to be responsible for the exercise-induced suppression in cytokine production.

Current indoor allergen levels of fungi and cats, but not house dust mites, influence allergy and asthma in adults with high dust mite exposure

We assessed the influence of current indoor levels of fungi, house dust mite allergen (Der p 1), and cat allergen (Fel d 1) on sensitization and asthma in adults. A total of 485 adults answered a questionnaire and had skin prick tests and lung function tests. Dust and air samples were collected from their bedrooms. The dust was analyzed for Der p 1, Fel d 1, and fungal biomass (ergosterol). Fungal propagules were measured in air samples. Current asthma was defined as having wheezed during the past 12 mo plus bronchial hyperreactivity (BHR) to methacholine. High exposure to total airborne fungi was associated with increased BHR, but perhaps paradoxically with a lower risk of being sensitized to fungi. Ergosterol levels in floor dust were a risk factor both for being sensitized to fungi and having wheezed within the last year. High Fel d 1 levels in floor dust were found to increase the risk of being sensitized to cats and in beds to increase the risk of current asthma. Although Der p 1 levels in homes were high, people exposed to high Der p 1 levels in floor dust were less likely to be sensitized to house dust mites or to have wheezed within the past year. Current indoor levels of fungi and Fel d 1, but not Der p 1, influenced sensitization and asthma in adults with high dust mite exposure.

[Breast-conserving surgery and irradiation for early breast cancer: value of surgical clips in the surgical cavity]

PURPOSE

To evaluate, qualitatively and quantitatively, the role of surgical clips in planning the tumor bed electron or brachytherapy boost in patients undergoing breast-conserving surgery and radiotherapy.

PATIENTS AND METHODS

In 60 patients with breast cancer stage I or II, the excision cavity boundaries were marked by clips at surgery. Patients received a boost with brachytherapy (n = 51) or electron beam (n = 9) after whole breast irradiation. The boost target volume was first planned using clinical, mammography and operative information and its accuracy evaluated by screening the surgical clips and, if necessary, adjusting the field to encompass all clips and to include the scar. Dosimetry was retrospectively performed for each brachytherapy patient and for each surgical clip.

RESULTS

It was necessary to modify the target volume field in 11 cases (18%). The average dose received by the surgical clips was 116.1% of the dose delivered to the reference isodose (median: 101.75%, range: 16-457%). However, dose heterogeneity was important in the same patient and between patients.

CONCLUSION

Delineation of the boost target volume with surgical clips is more accurate than with clinical landmarks alone but this technique does not allow measurements of the clip-chest wall and clip-skin distances. Virtual simulation with CT-scan cuts is recommended for optimising boost planning.

Circulating monocytes are not the source of elevations in plasma IL-6 and TNF-alpha levels after prolonged running

The present study was undertaken to examine the effect of prolonged running on monocyte intracellular cytokine production and plasma cytokine concentration. Blood samples were collected 1 h before, immediately after, 2 h after, and 24 h after a competitive marathon run. There was no change in the number of cells spontaneously producing tumor necrosis factor (TNF)-alpha; however, there was a decrease in the number of cells producing interleukin (IL)-1alpha and IL-6 (P < 0.01) postexercise. In contrast, there was an increase in the number of monocytes that responded to lipopolysaccharide stimulation by producing IL-1alpha, TNF-alpha, and IL-6 (P < 0.01) immediately and 2 h postexercise; however, these cells contained less cytokine (P < 0.05). Plasma IL-6, TNF-alpha, epinephrine, norepinephrine, and cortisol concentrations were markedly increased (P < 0.01) postexercise. These data demonstrate that circulating monocytes are not the source of elevated levels of plasma IL-6 and TNF-alpha after prolonged running. In addition, it is likely that stress hormones result in a decrease in the amount of cytokine produced by LPS-stimulated cells postexercise.

Effect of prolonged, submaximal exercise and carbohydrate ingestion on monocyte intracellular cytokine production in humans

The present study was undertaken to examine the effect of exercise and carbohydrate (CHO) ingestion on intracellular monocyte cytokine production. Subjects performed 2 h of cycling at 70 % peak pulmonary O2 uptake (VO2,peak) while ingesting either an 8 % CHO beverage or a sweet placebo. Whole blood was incubated with (stimulated) or without (spontaneous) lipopolysaccharide (LPS) and surface stained for monocyte surface antigens. The cells were permeabilised, stained for intracellular cytokines and analysed using flow cytometry. Exercise had no effect on the number of monocytes spontaneously producing cytokines, but the number of stimulated IL-1alpha-, TNF-alpha- and IL-6-positive monocytes were elevated (P < 0.01) immediately post-exercise and 2 h post-exercise. These stimulated cells produced less (P < 0.05) TNF-alpha immediately post-exercise, and less (P < 0.05) TNF-alpha and IL-1alpha 2 h post-exercise. There was a small, but significant increase (P < 0.05) in the plasma IL-6 concentration immediately post-exercise. Exercise resulted in an elevation (P < 0.01) in the plasma adrenaline concentration in the placebo trial, and ingestion of CHO attenuated this increase. CHO ingestion had no effect on monocyte cytokine production, plasma IL-6 or circulating leukocyte numbers. These data suggest that circulating monocytes are not the origin of increased levels of plasma IL-6 during exercise: prolonged cycling exercise increased the number of monocytes producing cytokines upon stimulation, but these cells produced less cytokines post-exercise. In addition, attenuation of plasma adrenaline levels had no effect on plasma IL-6 or monocyte cytokine production.

[Hypophyseal surgical treatment of Cushing's disease in the child]

Cushing's disease in children is rare and not familar to pediatricians. We report here 7 cases concerning children between 8 and 16 years of age, treated by pituitary surgery with 1 to 9 year follow-up. A remission of hypercorticism was obtained in all cases. However, a pituitary deficiency requiring replacement opotherapy and/or a recurrence was observed in 5 out of 7 patients. From our experience and the review of literature (around 130 cases), Cushing's disease is more serious in children than in adult. We suggest therapeutic management with transsphenoidal surgery as the treatment of choice. Given the frequency of recurrence (13 à 54%) often late (9-12 years), we stress the need of regular and extended postoperative follow-up.

A reliable and valid home visit report for studies of asthma in young adults

Validated instruments are not available to assess the residential characteristics. The aim of this study was to assess the reliability and validity of an interviewer-administered home visit report. The validity of 48 items in the Home Visit Report was examined against: observations made by a researcher, measurements of relative humidity, cat allergen, and ergosterol, a biomaker of fungal exposure and a biochemical test. Test-retest reliability of 10 fixed residential characteristics was assessed comparing the responses obtained in the main study with the pilot study, Kappa, ANOVA and Wilcoxon Rank Sum tests were applied to assess the agreement and P < 0.05 was considered as statistically significant. Among 44 items examined for the validity against observations, there was a perfect or almost perfect agreement in 21 (kappa = 0.9-1) and substantial agreement (kappa = 0.6-0.8) in 19. Higher cat allergen levels were observed with cat ownership and cat being allowed indoors. Observed condensation was associated with relative humidity and observed mould was associated with ergosterol levels. The agreement on the type of carpet and the test was substantial (kappa = 0.6). Among 10 items examined for reliability, there was a perfect or almost perfect agreement in 9 (kappa = 0.9-1) and substantial agreement (kappa = 0.7) in one. In conclusion, the Home Visit Report validated in this study provides reliable and valid data.

Residential characteristics influence Der p 1 levels in homes in Melbourne, Australia

BACKGROUND

Exposure to house dust mite (HDM) allergens is an important risk factor for childhood asthma. Knowledge of environmental determinants of HDM allergen levels is essential before designing rational avoidance measures.

AIM

To investigate the effect of domestic characteristics on HDM allergen (Der p 1) levels in Melbourne homes.

METHODS

Dust was collected from bed and floor of the bedrooms in 485 houses over a period of one year. Dust was analysed for Der p 1 levels using an enzyme-linked immunosorbent assay. Temperature and relative humidity were measured at the visit. Details of residential characteristics were collected using a questionnaire. Statistically significant predictors of Der p 1 levels (P < 0.05) were identified using multiple linear regression.

RESULTS

High levels of Der p 1 were observed in the floors (geometric mean 17.2 microg/g fine dust) as well as in the beds (geometric mean 20.3 microg/g fine dust). Der p 1 levels in the floor dust were significantly lower in winter and spring. They were higher in houses built before 1980 and those with central heating, weather board walls, damp bedrooms or fitted old wool carpets. Der p 1 levels in bed dust were significantly higher in houses built before 1980, with wooden floors built on stumps, with high relative humidity, with visible mould in the room, in beds with an old mattress or in beds without a quilt.

CONCLUSIONS

We would encourage construction of homes without carpets, wooden floors on stumps or weather board walls.

Immunotherapy of allergy: anergy, deletion, and immune deviation

Decreased allergen-specific T cell proliferation and dysregulated cytokine synthesis accompany allergen immunotherapy, consistent with mechanisms of anergy and immune deviation. Recent studies emphasise the pivotal role of decreased T cell IL-4:IFN-gamma ratios. A landmark clinical trial of T cell epitope peptides for venom-immunotherapy shows efficacy and safety; murine models suggest intramolecular epitope-suppression inhibits responses to the whole allergen.

Immune response to a single bout of exercise in young and elderly subjects

The purpose of this investigation was to examine alterations in lymphocyte proliferation activity and T cell subsets following an acute bout of exercise in young and old subjects. Six young (26+/-3 years) and nine old (69+/-5 years) male subjects were tested at rest and immediately after 20 min of submaximal exercise at 50% peak work capacity. Arterial blood was sampled from an indwelling catheter for catecholamine and immunology assays. Peripheral blood lymphocytes were isolated for mitogen-induced phytohemagglutinin (PHA) proliferation capacity. Lymphocyte subsets were analyzed by dual-labeled flow cytometry. As has been shown in previous studies, baseline proliferative responsiveness was significantly lower in the old (down 22%) compared to the young subjects. In response to submaximal exercise, proliferative responsiveness to PHA increased significantly in the young subjects (up 55%), however, for the old subjects this response did not differ significantly from resting values (up 18%). The number of total lymphocytes, as well as CD4+ and CD8+ T cell subsets, at rest were lower for old subjects compared with young. Exercise-induced increases in T cell subset populations were similar across age groups. It was concluded that, while having lower initial T cell numbers and PHA responsiveness, immunoresponsiveness during a single bout of exercise is, in general, maintained in old when compared to young individuals.

An approach to the synthesis of biological tissue

Mathematical phantoms developed to synthesize realistic complex backgrounds such as those obtained when imaging biological tissue, play a key role in the quantitative assessment of image quality for medical and biomedical imaging. We present a modeling framework for the synthesis of realistic tissue samples. The technique is demonstrated using radiological breast tissue. The model employs a two-component image decomposition consisting of a slowly, spatially varying mean-background and a residual texture image. Each component is synthesized independently. The approach and results presented here constitute an important step towards developing methods for the quantitative assessment of image quality in medical and biomedical imaging, and more generally image science.

Immunological studies of herpes simplex virus infection in children with atopic eczema

This study examines the role of immune defence mechanisms in herpes simplex virus (HSV) infections in atopic eczema and whether impairment of these mechanisms explains the susceptibility of some children with atopic eczema to cutaneous HSV infections. Ten children with eczema herpeticum and 13 with atopic eczema and recurrent HSV infection affecting multiple skin sites were studied, together with relevant control groups. In all children with atopic eczema, in vitro lymphoproliferation in response to stimulation with concanavalin A (Con A) was significantly decreased and natural killer (NK) cells (CD16 + 56) were reduced compared with non-atopic controls. IL-2 receptors, a marker for lymphocyte activation, were decreased during the acute phase of eczema herpeticum, and for 1 month thereafter. A positive stimulation index (> 3) to HSV antigen, and high HSV IgG antibody titres measured by ELISA, Western blotting and neutralization assay, were seen in children with eczema herpeticum by 6 weeks, and also in children with atopic eczema and recurrent HSV infections. No evidence of an HSV-specific immune defect (either cell-mediated or humoral) was found in atopic eczema. Impairment of cell-mediated immunity in atopic eczema was suggested by the reduced response to Con A. It is likely that reduced numbers of circulating NK cells and a decrease in IL-2 receptors during early eczema herpeticum contribute to the susceptibility of children with atopic eczema to cutaneous HSV infections.

T cell receptor and immunoglobulin gene rearrangement analysis as a laboratory aid in the diagnosis of human malignant lymphoproliferative diseases

The identification of clonal rearrangements of the immunoglobulin heavy chain and T cell receptor beta chain gene loci by Southern blot analysis has led to advances in the diagnosis and classification of lymphoproliferative disorders. This paper reviews our experience with this technique over a three and a half year period. Specimens from 99 patients with suspected haematological malignancy were tested for leucocyte immunophenotype and immunoglobulin or T cell receptor gene rearrangement. Genotyping provided evidence of clonality in malignancies from 28 patients and demonstrated malignant cell lineage in eight patients not formally deduced from immunophenotyping alone. Our findings suggest that this technique can be employed in conjunction with immunophenotyping to aid in the determination of malignant cell lineage derivation and identification of malignant cell clonality, as well as potentially estimating the extent of disease, detecting relapse, and monitoring disease progression.

[Hepatic schistosomiasis and sarcoidosis with voluminous subdiaphragmatic adenopathies]

The authors report a case of a West-Indian with sarcoidosis and peripheral, mediastinal and, above all, sub-diaphragmatic lymph nodes. The latter were very large and palpable through the abdomen, confirmed by lymphography and found to be due to S. Mansomi schistosomiasis. Liver biopsy carried out under peritoneoscopy, showed schistosomal granulomatosis with sarcoidosic granulomatosis. The authors consider that the rareness of this association is only apparent and does not correspond to the frequency of bilharziasis nor that of sarcoidosis in these subjects. They emphasize the mistakes which may result in interpretation of liver biopsy. They recall a few special characteristics of sarcoidosis in West-Indians, in particular, the possibility of failure of corticosteroid therapy as in their case, due to the onset of miliary lung disease under treatment, and show the lymphographic appearances of sarcoidosis.

[Study of fetal heart rate in deliveries complicated by fetal acidosis]

A study has been carried out on the parameters of the graph of the fetal heart rate (the basal rate and dips) in 44 cases of acute fetal distress with a pH lower than 7.2 in the blood and in 30 normal deliveries. The statistical analysis confirms that there is a significant rise in the number of heart rate abnormalities such as persistent bradycardia or persistent tachycardia and with dips during deliveries with fetal acidosis. The frequency of these abnormalities increases with the degree of acidosis. Sometimes the abnormalities in the fetal heart rate precede the appearance of the acidosis. All the same the discovery of these abnormalities does not by itself make a precise diagnosis of fetal distress because we do find these abnormalities in a certain number of cases even in normal deliveries. Only measuring fetal pH at a definite time can establish the diagnosis of fetal distress and the severity of the condition.