Total circulating red cells versus haematocrit as the primary descriptor of oxygen transport by the blood

Peripheral haematocrit (PCV) is the traditional target and monitor in many transfusion regimens. Without negating the importance of PCV as a determinant of whole blood viscosity, the present article outlines two important reasons why the red cell volume (RCV) should replace PCV in the central target role during blood transfusion in intensive care and other emergency situations: 1. PCV reflects both RCV and plasma volume (PV) and is therefore not directly proportional to the total blood oxygen carrying capacity. At best, the relationship between PCV and RCV is hyperbolic and this is often overlooked when relating the two parameters in practice. At worst, the hyperbolic relationship is unreliable because PV and RCV can vary independently and the PCV is a fluctuating ratio of variable numbers. 2. PCV is not a good indicator of blood volume (BV), which is another important determinant of oxygen delivery to tissues and a crucial parameter in intensively managed patients. BV is directly proportional to RCV and this relationship also is often overlooked in clinical practice. The recommended values for RCV are 30 ml/kg in men. 25 ml/kg in women and between 30 ml/kg and 45 ml/kg in neonates within the first week of life.

Heterogeneity in hormone receptor status in primary and metastatic endometrial cancer

The rationale for endocrine therapy in patients with advanced endometrial carcinoma may be based on the presence of estrogen or progesterone receptors in the primary tumor. A study was designed to evaluate tumor cell heterogeneity of steroid hormone receptors in the primary and metastatic sites in endometrial cancer. Primary endometrial cancer tissue samples from 10 patients and 16 metastatic tumor sites were simultaneously analyzed for estrogen and progesterone receptors, using a radioligand biochemical assay. The primary tumor was estrogen receptor (ER) and progesterone receptor (PR) positive in 70 and 60% of the patients, respectively. The metastatic sites were ER positive in 63% and PR positive in 25%. The primary tumor tissue and the metastatic disease showed an identical ER and PR status in only 25 and 19%, respectively. Four patients had multiple metastatic sites analyzed. In two of four patients the PR values, and in three of four patients the ER values, in these metastatic sites were discordant. These data support the concept of tumor cell heterogeneity for steroid hormone receptors in endometrial cancer. To optimize treatment planning, it may be important to biopsy primary, metastatic, and recurrent tumor sites for individual analysis of receptor activity.

Recurrent calcific periarthritis, erosive osteoarthritis and hypophosphatasia: a family study

We describe a mother and 2 daughters with familial recurrent calcific periarthritis in a family with an inherited tendency to develop generalized osteoarthritis (OA). Low levels of serum alkaline phosphatase were found in 1 of the daughters while the mother developed erosive OA in later life. HLA typing was noncontributory. However, the 3 individuals with periarthritis possessed blood group A+, while the 6 unaffected family members were O+. The experience of this family adds weight to the case that recurrent calcific periarthritis may be due to an inherited abnormality of alkaline phosphatase production and suggest that this may also be responsible for the recently observed association of calcific periarthritis and erosive OA.

Postoperative hypoxaemia: mechanisms and time course

Postoperative hypoxaemia results predominantly from two mechanisms. Gas exchange is impaired during anaesthesia as a result of reduced tone in the muscles of the chest wall and probably alterations in bronchomotor and vascular tone, and the resulting changes persist into the postoperative period. In addition, there is an abnormality of control of breathing, which results in episodic obstructive apnoea. These episodes continue for several days after operation and are related to sleep pattern and analgesic administration, although the precise effects of different analgesic regimens have not been evaluated. Oxygen administration is effect in reducing the degree of hypoxaemia.

Red cell volume and cardiac output in anaemic preterm infants

To test the hypothesis that haemoglobin concentration is a poor predictor of benefit from transfusion in preterm infants, and that red cell volume is the most important indicator of anaemia, 24 preterm infants receiving red cell transfusions had red cell volume, haemoglobin concentration, and cardiac output measured before and after transfusion. Red cell volume was measured either using dilution of autologous fetal haemoglobin with donor adult haemoglobin, or with a new technique using biotin as a red cell label. The two techniques give similar results. Mean (SD) values before transfusion were 27.4 (13.3), and after transfusion 45.0 (13.7) ml/kg. Cardiac output was measured using imaging and Doppler ultrasonography, and fell with transfusion from mean 286 (121) to 251 (95.6) ml/kg/min. The red cell volume before transfusion correlated well with changes in cardiac output following transfusion, infants with a red cell volume before transfusion of less than 25 ml/kg showing a fall in cardiac output, and those with a red cell volume of greater than 25 ml/kg not showing a significant fall. There was no correlation between haemoglobin concentration, packed cell volume, or change in packed cell volume with changes in cardiac output after transfusion. A red cell volume of 25 ml/kg seems to be critical in preterm infants with anaemia, and infants with values below this are those most likely to benefit from transfusion.

Lack of weight gain associated with short-term astemizole treatment

The effect of treatment with astemizole for three weeks on weight was assessed in 44 patients with seasonal allergic rhinitis who participated in a randomized, double-blind, placebo-controlled clinical trial. Astemizole 10-mg tablets and identical placebo tablets were used. Compared with baseline, weight increased significantly in astemizole-treated patients (1.07 +/- 1.39 kg; p = 0.0004); however, the mean change in weight in astemizole-treated patients was not statistically significantly different than that seen in placebo-treated patients (0.85 +/- 1.68 kg). No relationship was found between changes in weight and age, sex, initial weight, percentage of obesity, and plasma astemizole concentrations.

In vitro marginal microleakage: examination of measurements used in assessment

Premolar teeth with Class II amalgam restorations placed after the application of cavity varnish (Group A), a light cured glass ionomer base (Group B) and 40 per cent polyacrylic acid as a pretreatment agent, followed by unset cermet cement (Group C) were examined for marginal leakage using dye penetration and image analysis. Including amongst the parameters examined were linear leakage length and leakage area, which were found to have no consistent correlation. Group A and C did not generally show significant differences in the parameters examined, whereas Group B exhibited significantly less linear leakage (P less than 0.001), and significantly less leakage area when the stained area was expressed as a percentage of available dentine (P less than 0.001). While allowing some linear leakage, it was found that the light cured glass ionomer base appeared to prevent the dye from entering the dentine. It is concluded that an assessment based solely on the leakage length is inadequate and that some measurement of penetration into dentine should be included in order to fully assess the microleakage potential of a material or technique.

Ovarian conservation in placental site trophoblastic tumor

While isolated reports on the management and natural biology of placental site trophoblastic tumor (PSTT) continue to accumulate, little attention has been given to ovarian conservation in the surgical management of this disease. Review of the literature reveals ovarian involvement by this tumor to be infrequent and, when present, grossly apparent at laparotomy. In the reported cases, grossly normal ovaries did not contain pathologic evidence of tumor. This study reports two additional cases in which at least one ovary was preserved. Until more reliable criteria are available for predicting which cases of PSTT will pursue a malignant course, the option of ovarian conservation should be available to young patients requiring abdominal surgery, if the disease remains confined to the uterus.

Virulence of papillary endometrial carcinoma

While uterine papillary serous carcinoma (UPSC) has been well described as a virulent subtype of endometrial adenocarcinoma (AC), with behavior similar to that of papillary serous ovarian carcinoma, the papillary endometrial (PE) variant has not been well characterized. We studied 117 patients with endometrial carcinoma identified by our tumor registry, pathology files, and practice records from March 1981 to February 1989: 76 with AC, 26 with PE, and 15 with UPSC. Age and demographic data were similar for all three groups. All of the AC patients, 84% of PE patients, and 87% of UPSC patients had early-stage disease by clinical exam; however, 10% of AC patients, 23% of PE patients, and 87% of UPSC patients had extrauterine disease at surgery (P less than 0.05). Deep myometrial invasion occurred in 29% of AC patients, 36% of PE patients, and 60% of UPSC patients (P less than 0.05). Comparative analysis of the PE and UPSC groups revealed more marked nuclear anaplasia (P less than 0.05) and more frequent vascular space involvement (nonsignificant) in the UPSC group. At 3 years, 75% of the AC group was alive without disease. In contrast, the median progression-free interval for the PE group was 33 months, and for the UPSC group, 9 months (P less than 0.05). These data suggest a transition of increasing virulence corresponding with increasing papillary features, from AC to PE to UPSC. The papillary feature may be a new, significant risk factor in endometrial carcinoma.

Postoperative hypoxaemia: comparison of extradural, i.m. and patient-controlled opioid analgesia

Arterial oxygen saturation (SaO2) was analysed continuously before and for 24 h after lower abdominal surgery in 30 patients breathing air using one of three postoperative analgesic regimens: i.v. diamorphine using a patient-controlled analgesia system (PCAS), extradural diamorphine or i.m. morphine. Hypoxaemia was defined as SaO2 less than 94% for more than 6 min h-1. Before operation there was no difference between the three analgesia groups assessed by the duration when SaO2 was less than 94%. After operation the pattern of SaO2 vs time distribution was either stable, with little variation from hour to hour with no hypoxaemia, or unstable with large variation with 30% of patients hypoxaemic. Thus three patterns of SaO2 distribution were seen in the postoperative period: stable without hypoxaemia (4/10 PCAS, 0/10 extradural, and 1/10 i.m. patients), unstable without hypoxaemia (4/10 PCAS, 5/10 extradural and 7/10 i.m. patients) and unstable with prolonged nocturnal periods with SaO2 less than 94% for a mean of 17.7 min h-1, 95% confidence limits (CL) 10-25 min h-1, (2/10 PCAS, 2/10 i.m. and 5/10 extradural patients). Before operation, the unstable group with hypoxaemia spent longer at less than 94% SaO2 (mean 4.8 min h-1, 95% CL 1.0-8.6 min h-1) than the stable group (mean 0.4 min h-1, 95% CL 0.17-0.61 min h-1) and this was a predictor of postoperative hypoxaemia. Hypoxaemia occurred in all analgesia groups, but extradural diamorphine tended to cause longer periods. Some patients at risk of postoperative hypoxaemia may be predicted by preoperative monitoring of SaO2 although extradural diamorphine boluses were associated with hypoxaemia in patients with normal preoperative values.

Measurements of pulmonary mechanics prior to the elective extubation of neonates

We measured total respiratory system compliance (CRS) and resistance (RRS) by the passive expiratory flow technique prior to the elective extubation of 61 neonates with a history of respiratory distress syndrome. Successful trials of extubation were characterized by a higher mean value of CRS when compared to trials that led to reintubation (1.52 vs. 1.10 mL/cm H2O, P = 0.004). Low values of CRS (0.9 mL/cm H2O or less) were invariably associated with extubation failure, whereas high values of CRS (1.3 mL/cm H2O or greater) were associated with extubation success in 94% of patients. A higher mean value of RRS was recorded in the group of infants who failed extubation when compared to those who were successful (0.22 vs. 0.17 cm H2O/mL/s, P = 0.042). We propose that measurements of pulmonary mechanics, particularly CRS, may be useful in identifying infants who will be at risk for extubation failure.

The quantitative evaluation of acute lung injury

The lung represents a complex barrier between air and blood. Subtle changes in the permeability of this barrier can be brought about by injury and only later do they become clinically and radiologically detectable. Techniques using radioactive traces offer a way of quantifying the degree of lung injury and so will aid the development of new forms of therapy.

Clearance of charged and uncharged dextrans from normal and injured lungs

To examine how molecular charge affects the transfer of molecules across the alveolar-capillary barrier, we prepared the following dextrans of equivalent molecular size (mol wt 10,000) but varying molecular charge: neutral dextran, cationic DEAE dextran, and anionic dextran sulfate. These were labeled with 99mTc. The lungs of three groups of anesthetized rabbits were insufflated with dextran aerosols, with six rabbits receiving each type, and the half-time pulmonary clearance (t1/2) was measured. Control t1/2's (95% confidence limits) were 95 (74-120), 227 (192-268), and 291 (246-345) min for neutral, cationic, and anionic dextrans, respectively. One week later, when the same animals were restudied 4 h after 3 micrograms/kg iv endotoxin, t1/2's were 102 (75-139), 167 (149-187), and 126 (102-154) min, respectively. After 30 min during this repeat study, animals were ventilated with 20 breaths of cigarette smoke, which acutely increased the clearance rate to 34 (26-46), 25 (20-31), and 13 (7-24) min, respectively. Mean carboxyhemoglobin levels were not significantly different in the three groups: 13.6, 12.7, and 11.1%, respectively. These results demonstrated that neutral dextrans showed the same clearance rate before and after endotoxin, whereas the charged dextrans had a significantly faster clearance after endotoxin. After smoke exposure the anionic dextran left the lung more rapidly than the neutral dextran. Thus molecular charge affects solute transfer across the alveolar-capillary barrier in both normal and injured lungs, and an effect of endotoxin on the lung can be detected with charged dextrans but not with neutral dextran.

Relationships between multidimensional competitive state anxiety and cognitive and motor subcomponents of performance

This study examined the relationship between multidimensional competitive state anxiety and cognitive (i.e. digit span) and motor (i.e. perceptuo-motor speed) subcomponents of performance in an experimental group of hockey players during the period leading up to an important hockey match, and also in a control group of hockey players before a routine training session. Using a 'time-to-event' experimental paradigm, an increase in somatic anxiety 20 min before the hockey match was accompanied by improved perceptuo-motor speed performance. Stepwise multiple regression analyses showed that somatic anxiety was negatively related to digit span performance, whilst somatic anxiety and self-confidence were positively related to perceptuo-motor speed performance. These findings suggest that somatic anxiety may be an important source of performance variance.

Strategic planning in academic medicine: a departmental case study analysis

Family medicine departments face a variety of external and internal pressures that make astute planning imperative. A systematic planning process produces measurable outcomes, timetables to evaluate results, and assignments for individual responsibility. Strategic planning is discussed as it occurred during a year-long planning process in a family medicine department. Through the use of an external consultant and through the efforts of the department's division directors, a set of plans were written and approved for the residency program, clinical services, predoctoral education, geriatric education, research and development section, and the administration of the department. The consultation and strategic planning procedure produced a candid analysis of the department's strengths and growth needs, and specified the contributions that will be needed by all faculty to achieve the organization's goals.

Pulmonary clearance of 99mTc-DTPA in the diagnosis and evolution of increased permeability pulmonary oedema

We measured pulmonary clearance of aerosolised 99mtechnetium-labelled diethylenetriaminepentacetate (99mTc-DTPA) in thirty-four patients with acute respiratory dysfunction. Results were expressed as a half-time clearance from lung to blood (T1/2). In sixteen non-smoking patients with acute lung injury, clearance was monoexponential, median T1/2 11, range 4-40 min, and in five multi-exponential, median rapid T1/2 3 min, with a slower median T1/2 of 18 min (range 2-4 and 15-31 min respectively). Clearance was significantly (P less than 0.0001) more rapid than normal non-smoking subjects previously studied (median T1/2 70, range 37-182 min). Three smokers with acute lung injury had T1/2S of 5, 18 and 22 min, not significantly (P greater than 0.05) quicker than normal smokers previously studied (median T1/2 20, range 6-73 min). One smoking lung-injured patient had an abnormal multi-exponential 99mTc-DTPA clearance. Four patients with cardiogenic pulmonary oedema had T1/2S within the normal range. Repeated measurements made on nine patients with acute lung injury showed that clearance remained abnormally rapid despite improvements in lung radiographic appearance and gas exchange. We conclude that the 99mTc-DTPA technique provides a virtually non-invasive measure of alveolar-capillary barrier dysfunction in non-smoking patients with acute lung injury.

Analysis of insertion mutants reveals two new genes in the pNRC100 gas vesicle gene cluster of Halobacterium halobium

The archaebacterium, Halobacterium halobium, achieves buoyancy through synthesis of intracellular gas-filled vesicles. The plasmid-encoded gene (gvpA) specifying the major structural gas vesicle protein has previously been cloned and sequenced allowing the analysis of high-frequency mutations to the vesicle negative phenotype. Among eighteen gas vesicle mutants analyzed, four were observed to contain insertion elements 0.2 to 2 kb upstream of the structural gene. To explain the phenotype of these mutants, the upstream area was analyzed by DNA sequencing and transcriptional mapping. This analysis showed the presence of two open reading frames, gvpD and gvpE, which are of opposite transcriptional orientation to gvpA (gene order gvpA-D-E). gvpD begins 201 nucleotides from the gvpA structural gene and is 1608 nucleotides long while gvpE begins two nucleotides from the 3'-end of gvpD and is 573 nucleotides long. Primer extension analysis showed the occurrence of divergent promoters in the gvpA-gvpD intergenic region with the transcription start sites separated by 109 nucleotides. The sites of three insertion sequences in gas vesicle mutants mapped within gvpE while the fourth insertion site mapped near the N-terminal coding region of gvpD. Homology between the gvpDE gene region and a chromosomal site in a H. halobium NRC-1 derivative and in several other Halobacterium strains was identified by Southern hybridization.

The interactions of desferrioxamine and hydroxypyridone compounds with haemoglobin and erythrocytes

The iron chelator desferrioxamine has been applied in many studies of pathological states by several investigators. The resulting decreases in cellular and tissue damage have been interpreted as an indication of the involvement of iron-mediated radical species. Although the nature and location of the iron species have not been identified, the assumption has often been made that desferrioxamine is able to enter cells. This paper reports investigations of the ability of desferrioxamine to cross the erythrocyte membrane in comparison with that of specific hydroxypyridone iron chelators by assessing their interaction with haemoglobin.

Direct phenotypic and genotypic detection of a recombinant pseudomonad population released into lake water

As a system for studying the fate of genetically engineered microorganisms in the environment, we have previously constructed recombinant plasmids encoding a xylE marker gene (C. Winstanley, J. A. W. Morgan, R. W. Pickup, J. G. Jones, and J. R. Saunders, Appl. Environ. Microbiol. 55:771-777, 1989). A series of direct membrane filter methods have been developed which facilitate the detection of bacterial cells harboring the xylE gene, its product, catechol 2,3-dioxygenase, and catechol 2,3-dioxygenase enzyme activity directly from water samples. These methods enable detection of recombinant populations at concentrations as low as 10(3) to 10(4) cells ml of lake water-1. Direct detection facilitates ecological studies of a range of bacterial strains containing the marker system in aquatic environments. The fate of a recombinant pseudomonad population in lake water was assessed by a combination of colony-forming ability, direct counts, and direct detection of the xylE gene and phenotypic expression of its product.

Effect of propofol on the auditory evoked response and oesophageal contractility

Six patients were anaesthetized with 70% nitrous oxide in oxygen supplemented by infusion of propofol 40, 80, 120, 160 and 200 micrograms kg-1 min-1 sequentially in successive 10-min periods. Auditory evoked response (AER) and lower oesophageal contractility (LOC) were monitored. The AER findings were consistent with those noted in previous studies of i.v. agents. Early cortical waves showed attenuation of Pa and Nb amplitude (P less than 0.01) and increase in Pa and Nb latency (P less than 0.01; P less than 0.05) with increasing blood concentrations of propofol. Brainstem waves were not affected significantly. LOC, provoked and spontaneous, showed no consistent relationship with blood concentration of propofol. The two variables AER and LOC were not related.