A Quantitative Analysis of Surgical Smoke Exposure as an Occupational Hazard

OBJECTIVE

We hypothesized that OR airborne PM was different in quantity and mutagenic potential than office air and cigarette smoke.

SUMMARY OF BACKGROUND DATA

Exposure to surgical smoke has been equated to cigarette smoking and thought to be hazardous to health care workers despite limited data.

METHODS

PM was measured during 15 operations in ORs with 24.8 ± 2.0 air changes/h, and in controls (cigarettes, office air with 1.9-2.9 air changes/h). Mutagenic potential was assessed by gamma Histone 2A family member X staining of DNA damage in small airway epithelial cells co-cultured with PM.

RESULTS

Average PM concentration during surgery was 0.002 ± 0.002 mg/m3 with maximum values at 1.08 ± 1.30 mg/m3. Greater PM correlated with more diathermy (ρ = 0.69, P = 0.006). Values were most often near zero, resulting in OR average values similar to office air (0.002 ± 0.001 mg/m3) (P = 0.32). Cigarette smoke average PM concentration was significantly higher, 4.8 ± 5.6 mg/m3 (P < 0.001). PM collected from 14 days of OR air caused DNA damage to 1.6% ± 2.7% of cultured cells, significantly less than that from office air (27.7% ± 11.7%, P = 0.02), and cigarette smoke (61.3% ± 14.3%, P < 0.001).

CONCLUSIONS

The air we breathe during surgery has negligible quantities of PM and mutagenic potential, likely due to low frequency of diathermy use coupled with high airflow. This suggests that exposure to surgical smoke is associated with minimal occupational risk.

Understanding auditory verbal hallucinations: a systematic review of current evidence

OBJECTIVE

Auditory verbal hallucinations (AVHs) are core features of psychotic illness and remain significant in predicting poor outcome and risk. There has been a wide range of approaches to understanding these experiences.

METHOD

A systematic literature review summarizing different methods of investigation and their results; phenomenology, descriptive psychopathology, psychological, cognitive neurobiology, and neuroimaging.

RESULTS

A number of 764 papers and texts were screened and 113 reviewed. Phenomenological studies are comparably few in number, and psychopathology remains based on concepts defined in the early 20th century. Psychological models focus on voice content and emotional reaction, and suggest a continuum of AVHs from normal experience. Neuropsychological models include AVHs as misattribution of inner speech, whilst functional neuroimaging studies focus on the spontaneous activity and connectivity of auditory networks.

CONCLUSION

There has been a large growth in research on AVHs in recent decades dominated by neurobiological and neuroimaging studies. Future research should include focus on phenomenological aspects and AVHs change over the course of developing illness. Integration between branches of enquiry is needed, and the risk is that without this, models are proposed and investigated that bear scant relevance to the symptom itself.

Safety, efficacy and glucose turnover of reduced prandial boluses during closed-loop therapy in adolescents with type 1 diabetes: a randomized clinical trial

AIMS

To evaluate safety, efficacy and glucose turnover during closed-loop with meal announcement using reduced prandial insulin boluses in adolescents with type 1 diabetes (T1D).

METHODS

We conducted a randomized crossover study comparing closed-loop therapy with standard prandial insulin boluses versus closed-loop therapy with prandial boluses reduced by 25%. Eight adolescents with T1D [3 males; mean (standard deviation) age 15.9 (1.5) years, glycated haemoglobin 74 (17) mmol/mol; median (interquartile range) total daily dose 0.9 (0.7, 1.1) IU/kg/day] were studied on two 36-h-long visits. In random order, subjects received closed-loop therapy with either standard or reduced insulin boluses administered with main meals (50-80 g carbohydrates) but not with snacks (15-30 g carbohydrates). Stable-label tracer dilution methodology measured total glucose appearance (Ra_total) and glucose disposal (Rd).

RESULTS

The median (interquartile range) time spent in target (3.9-10 mmol/l) was similar between the two interventions [74 (66, 84)% vs 80 (65, 96)%; p = 0.87] as was time spent above 10 mmol/l [21.8 (16.3, 33.5)% vs 18.0 (4.1, 34.2)%; p = 0.87] and below 3.9 mmol/l [0 (0, 1.5)% vs 0 (0, 1.8)%; p = 0.88]. Mean plasma glucose was identical during the two interventions [8.4 (0.9) mmol/l; p = 0.98]. Hypoglycaemia occurred once 1.5 h post-meal during closed-loop therapy with standard bolus. Overall insulin delivery was lower with reduced prandial boluses [61.9 (55.2, 75.0) vs 72.5 (63.6, 80.3) IU; p = 0.01] and resulted in lower mean plasma insulin concentration [186 (171, 260) vs 252 (198, 336) pmol/l; p = 0.002]. Lower plasma insulin was also documented overnight [160 (136, 192) vs 191 (133, 252) pmol/l; p = 0.01, pooled nights]. Ra_total was similar [26.3 (21.9, 28.0) vs 25.4 (21.0, 29.2) µmol/kg/min; p = 0.19] during the two interventions as was Rd [25.8 (21.0, 26.9) vs 25.2 (21.2, 28.8) µmol/kg/min; p = 0.46].

CONCLUSIONS

A 25% reduction in prandial boluses during closed-loop therapy maintains similar glucose control in adolescents with T1D whilst lowering overall plasma insulin levels. It remains unclear whether closed-loop therapy with a 25% reduction in prandial boluses would prevent postprandial hypoglycaemia.

Glucose turnover after replacement of usual therapy by insulin in insulin-naive type 2 diabetes subjects

CONTEXT

Discontinuation of anti-hyperglycemic oral agents and initiation of insulin is recommended in certain clinical situations for inpatients with type 2 diabetes (T2D). The effects on glucose turnover when these agents are acutely withdrawn are poorly understood and may be of importance when insulin therapy is initiated.

OBJECTIVE

Our objective was to investigate alterations in glucose turnover after acute withdrawal of noninsulin therapy.

DESIGN AND SETTING

This was a randomized crossover study at a clinical research facility.

PARTICIPANTS

Participants included 12 insulin-naive subjects with T2D.

METHODS

Subjects attended two 24-hour visits. Standard therapy was discontinued and replaced by closed-loop insulin delivery during the intervention visit. Usual anti-hyperglycemic therapy was continued during the control visit. Systemic glucose appearance (Ra) and glucose disposal (Rd) were measured using a tracer dilution technique with iv [6,6-(2)H2]glucose.

RESULTS

Plasma glucose profiles during both visits were comparable (P = .48). Glucose Ra increased during the day (21.4 [19.5, 23.5] vs 18.6 [17.0, 21.6) μmol/kg/min, P = .019) and decreased overnight (9.7 [8.5, 11.4] vs 11.6 [10.3, 12.9] μmol/kg/min, P = .004) when the usual therapy was discontinued and replaced with insulin. Increased daytime glucose Rd (21.2 [19.4, 23.9] vs 18.8 [18.3, 21.7] μmol/kg/min, P = .002) and decreased overnight Rd (10.4 [9.1, 12.0] vs 11.8 [10.7, 13.7] μmol/kg/min, P = .005) were observed when the usual therapy was discontinued, whereas daytime peripheral insulin sensitivity was reduced (47.8 [24.8, 66.1] vs 62.5 [34.8, 75.8] nmol/kg/min per pmol/L, P = .034).

CONCLUSION

In T2D, acute discontinuation of anti-hyperglycemic therapy and replacement with insulin increases postprandial Ra and reduces peripheral insulin sensitivity. Insulin dose initiation may need to compensate for these alterations.

Exposure assessment of a mercury spill in a Nevada school -- 2004

BACKGROUND

Although mercury is toxic, few studies have measured exposure in children who handled elemental mercury briefly. In 2004, a student spilled approximately 60 milliliters of mercury at a Nevada school. Within 12 hours, all students were removed from the source of exposure. We conducted an exposure assessment at the school.

METHODS

We administered questionnaires and obtained urine samples from students. Using two-sample t-tests, we compared urine mercury levels from students who self-reported exposure to mercury levels of other students.

RESULTS

Two-hundred students participated, including 55/62 (89%) who were decontaminated. The students' geometric mean urine mercury level was 0.36 microg/L (95% confidence interval 0.32-0.40 microg/L). The student who brought the mercury to school was the only one to have an elevated urine mercury level (11.4 microg/L).

CONCLUSION

Despite environmental contamination, mercury exposure may have been minimized because of rapid identification of the elemental mercury spill and decontamination.

Computerized color-vision test based upon postreceptoral channel sensitivities

An automated, computerized color-vision test was designed to diagnose congenital red–green color-vision defects. The observer viewed a yellow appearing CRT screen. The principle was to measure increment thresholds for three different chromaticities, the background yellow, a red, and a green chromaticity. Spatial and temporal parameters were chosen to favor parvocellular pathway mediation of thresholds. Thresholds for the three test stimuli were estimated by four-alternative forced-choice (4AFC), randomly interleaved staircases. Four 1.5-deg, 4.2 cd/m2square pedestals were arranged as a 2 × 2 matrix around the center of the display with 15-minute separations. A trial incremented all four squares by 1.0 cd/m2for 133 ms. One randomly chosen square included an extra increment of a test chromaticity. The observer identified the different appearing square using the cursor. Administration time was ∼5 minutes. Normal trichromats showed clear Sloan notch as defined by log (ΔY/ΔR), whereas red–green color defectives generally showed little or no Sloan notch, indicating that their thresholds were mediated by their luminance system, not by the chromatic system. Data from 107 normal trichromats showed a mean Sloan notch of 0.654 (SD = 0.123). Among 16 color-vision defectives tested (2 protanopes, 1 protanomal, 6 deuteranopes, & 7 deuteranomals), the Sloan notch was between −0.062 and 0.353 for deutans and was <−0.10 for protans. A sufficient number of color-defective observers have not yet been tested to determine whether the test can reliably discriminate between protans and deutans. Nevertheless, the current data show that the test can work as a quick diagnostic procedure (functional trichromatism or dichromatism) of red–green color-vision defect.

Measuring synthesis rates of muscle creatine kinase and myosin with stable isotopes and mass spectrometry

We investigated a novel strategy for measuring the synthesis rate of proteins in skeletal and cardiac muscle. Mass isotopomer distribution analysis allows measurement of the isotopic enrichment of the true biosynthetic precursor for proteins (tRNA-amino acids), but cannot easily be applied to slow turnover muscle proteins due to insufficient isotope incorporation into multiply labeled species. Using a rapid turnover protein from the same tissue, however, might reveal tRNA-amino acid enrichment. We tested this strategy in rats on muscle creatine kinase (CK). A trypsinization peptide (3647u) containing 5 leucine repeats was identified by computer-simulated digestion of CK and then isolated from trypsin hydrolysates. Mass isotopomer abundances were determined by electrospray ionization-magnetic sector-mass spectrometry after in vivo administration of [(2)H(3)]leucine. Myosin heavy chain was also isolated and hydrolyzed to free amino acids. Muscle tRNA-amino acids were well labeled, by direct measurement. Enrichments of M(+1) and M(+2) mass isotopomers in the CK-peptide were measurable but low (consistent with a CK half-life of 3-10 days). Incorporation into skeletal muscle myosin indicated a half-life of 54 days. In conclusion, the general strategy of measuring protein kinetics by quantifying mass isotopomer abundances of mid-sized peptides from protein hydrolysates is effective, but CK does not turn over rapidly in muscle, contrary to previous reports. Identification of a rapid turnover muscle protein would be useful for this purpose.

Psychological distress of cancer and clinical trial participation: a review of the literature

The House of Commons Select Committee on Science and Technology 2000 state that currently less than 5% of adult patients with solid tumours are entered into clinical trials. They recommend that increasing the number of adult cancer patients entering clinical trials must become a high priority. Health-care providers need to prepare themselves for this proposed increase in trial participants by assessing the current status of care and implementing changes within the current infrastructure to provide optimal holistic care. Cancer can change a patient's life either for better or for worse. At one extreme, having cancer leads to enhanced appreciation of life and closer bonds with others. However, at the other extreme, cancer combined with its treatment is viewed as an event that evokes distress and emotional anguish taxing the individual's ability to cope. In the last 25 years, owing to the advent of clinical trials, progress has been made in cancer treatment. Clinical trials may be hailed as the saviour to many therapeutic dilemmas. Treatments are now available which can offer patients hope of cure. Nevertheless, many participants may fear, for the purpose of research, that they may be assigned to less than optimal therapy or that their care will be carried out in a sterile scientific atmosphere devoid of humane and personal consideration. These and other reasons may cause unacceptable personal distress that overrides the potential therapeutic gain. Cancer diagnosis coupled with the ramifications of clinical trial involvement can have significant psychological implications. They may trigger the onset of a mood disorder or exacerbate a present symptom. This article will identify mood disorders in the cancer population, focus on the participants' needs in the clinical trial arena and investigate the influence trial participation has on psychological status.

Postgraduate education for nurses: the Middlesex model

Nurse education has been subject to many changes and much debate and criticism over recent years. What has become increasingly evident is that with the changing nature of nursing within society, nursing curricula have to be more flexible and dynamic if they are to meet a multiplicity of needs. There is also a need to recognize that many levels of curricula will be required to prepare the nurses of the future. At Middlesex University the development of specialist practice programmes at postgraduate diploma level, and preparation of nurses for a higher level of practice at masters level has required the development of a new curriculum model which allows both the individualization of academic programmes to meet the needs of nurses, their clients and the organization in which they work, and the integration of development and learning through practice. This model is built on the results of an evaluation of an existing postgraduate programme in interprofessional health care. Key features of the curriculum development include a structured collaboration between student, practice mentor and academic supervisor, and the use of a professional development portfolio to individualize the academic programme and facilitate autonomous learning.

Fibronectin immobilized by a novel surface treatment regulates fibroblast attachment and spreading

In order to understand the influence of cell-adhesive molecules on anchorage-dependent cell behavior on biomaterial surfaces, a model system is required where these molecules can be applied to surfaces with controlled surface ligand density and resistance to the adsorption of additional proteins present in the medium. This study asked whether fibronectin could be immobilized in a controlled manner to a hydrophobic surface with a chemically modified triblock surfactant. ELISA studies indicated that variation of the soluble fibronectin concentration used for immobilization could be used to control the amount of fibronectin immobilized to the surface. Furthermore, fibroblasts seeded on these surfaces in 10% serum-containing medium attached and spread as a function of the amount of immobilized fibronectin. Surfaces treated with unmodified surfactant did not support cell attachment, suggesting that cell attachment and spreading were primarily regulated by the immobilized fibronectin with minimal interference from adsorption of serum proteins. Together, these results suggest that covalent immobilization to Pluronic F108 provides a method for studying cellular responses to cell adhesive proteins with little interference from competing adsorbates, even in the presence of complex biological fluids such as serum. This technique may be applicable to a variety of existing hydrophobic biomedical polymers as a basic science tool as well as for influencing cell behavior at implant interfaces.

arrow encodes an LDL-receptor-related protein essential for Wingless signalling

The Wnt family of secreted molecules functions in cell-fate determination and morphogenesis during development in both vertebrates and invertebrates (reviewed in ref. 1). Drosophila Wingless is a founding member of this family, and many components of its signal transduction cascade have been identified, including the Frizzled class of receptor. But the mechanism by which the Wingless signal is received and transduced across the membrane is not completely understood. Here we describe a gene that is necessary for all Wingless signalling events in Drosophila. We show that arrow gene function is essential in cells receiving Wingless input and that it acts upstream of Dishevelled. arrow encodes a single-pass transmembrane protein, indicating that it may be part of a receptor complex with Frizzled class proteins. Arrow is a low-density lipoprotein (LDL)-receptor-related protein (LRP), strikingly homologous to murine and human LRP5 and LRP6. Thus, our data suggests a new and conserved function for this LRP subfamily in Wingless/Wnt signal reception.

High resolution size determination of 20 nm colloidal gold particles by SedFFF

PURPOSE

Assessment of lower size limit of Sedimentation Field-Flow Fractionation (SedFFF), specifically to evaluate if the method is suitable to determine the size and size distribution of 20 nm colloidal gold particles with high resolution.

METHODS

Sedimentation Field-Flow Fractionation was used to determine the size of the colloidal particles. Due to the high density of gold it was possible to extend the lower size limit of SedFFF well below 20 nm. The size distribution of a gold colloid was obtained from the peak broadening caused by the polydispersity of the sample. The peak broadening due to instrumental imperfections was determined. For comparison purpose the particles were also sized using SEM and PCS.

RESULTS

The mean diameter of the particles was determined to be (20.87+/-0.05) nm, the standard deviation in size being 1.04 nm (about 5%). SEM could confirm that the particles are about 20 nm in diameter. A sizing with PCS was not possible. The particles have a strong tendency to aggregate and PCS yields a diameter that is much too large.

CONCLUSIONS

At optimized analytical parameters Sedimentation Field-Flow Fractionation is an effective method to measure the size of gold particles as small as 15 nm with an accuracy of about 0.1 nm. The polydispersity of the sample can easily be determined.

Prevalence and characteristics of children with serious hearing impairment in metropolitan Atlanta, 1991-1993

OBJECTIVES

There is a paucity of data describing the epidemiology of serious hearing impairment among children in the United States. This report provides information on the prevalence of serious hearing impairment among children born in the 1980s and living in the metropolitan Atlanta area in 1991-1993 and on the characteristics of children with serious hearing impairment.

METHODS

Data for this report are drawn from the Metropolitan Atlanta Developmental Disabilities Surveillance Program, an ongoing, active case-ascertainment system for mental retardation, cerebral palsy, hearing impairment, and vision impairment among children 3 to 10 years of age. Hearing impairment was defined as a bilateral, pure-tone hearing loss at frequencies of 500, 1000, and 2000 Hz averaging 40 decibels or more, unaided, in the better ear. Both severity and type of hearing loss were examined. Cross-sectional as well as birth cohort prevalence rates of serious hearing impairment were computed by sex and by race. The presence of mental retardation, cerebral palsy, vision impairment, or a seizure disorder was also assessed. An attempt was made to determine the probable etiology of a subset of the cases.

RESULTS

The average, annual prevalence rate for moderate to profound hearing loss was 1.1 per 1000. The prevalence rate increased steadily with age. Ninety percent of all cases for which the type of loss was recorded were sensorineural. The highest rate was seen among black male children (1.4 per 1000). Thirty percent of case children had another neurodevelopmental condition, most frequently mental retardation. Black male children also experienced the highest rate of presumed congenital hearing impairment. The mean age at which children with presumed congenital hearing impairment first met the surveillance case definition was 2. 9 years. A probable etiology could only be found for 22% of cases born in the study area.

CONCLUSIONS

The data presented here provide information on the descriptive epidemiology of serious hearing impairment among United States children. The reasons for the higher rates among black children, especially males, may be a fruitful direction for further research.

Measuring protein synthesis by mass isotopomer distribution analysis (MIDA)

The measurement of protein kinetics by isotopic techniques has been hindered by the long-standing difficulty of accurately measuring the isotope content of the biosynthetic precursor pool (aminoacyl-tRNA in tissues). Mass isotopomer distribution analysis (MIDA) is a stable isotope-mass spectrometric (MS) technique for measuring biosynthetic precursor enrichments from measurements on a polymeric product, based on combinatorial probabilities of labeled and unlabeled monomeric subunits. Proteins contain complex isotopomer patterns as a result of their relatively high molecular mass, however, so that resolution of the individual mass isotopomers in the polymeric product (an analytic requirement for MIDA) is technically difficult. An approach for measuring protein synthesis by MIDA is described and tested here: First, in vitro, using a synthetic peptide present in human serum albumin; and then, in vivo, for albumin synthetic rate in rats. A peptide contained in human serum albumin (SVVLLLR) and theoretically recoverable from trypsin/chymotrypsin proteolysis was synthesized by solid-phase peptide synthesis using known mixtures of natural abundance and [5,5, 5-2H3]leucine. Additionally, enriched and natural abundance peptides were mixed in vitro to simulate in vivo biosynthesis and to address problems of instrument accuracy, precision, and data management. The mass isotopomer patterns of the synthetic peptides were analyzed using electrospray ionization (ESI) with both magnetic sector and quadrupole mass analyzers. The resolution of the magnetic sector was superior to that of the quadrupole instrument, but accuracy and precision in the measurement of mass isotopomer abundances and kinetic parameters were comparable and both gave values close to those predicted. Next, rats were infused with [5,5,5-2H3]leucine intravenously, and a leucine-rich peptide was isolated and purified from trypsin-digested rat serum albumin (RHPDYSVSLLLR, 1456 Da) and then analyzed by ESI-MS using a magnetic sector instrument. Precursor pool enrichments and fractional synthetic rates (0.45 +/- 0.03 day-1, t1/2 = 1.53 +/- 0.09 days) were calculated. Biosynthetic rates of rat serum albumin were congruent with previously published values. In summary, measurement of protein synthesis and precursor pool enrichments by MIDA is technically feasible and practical in vivo using proteolytically derived peptides and ESI-MS analysis.

Underreading of the tuberculin skin test reaction

STUDY OBJECTIVE

The tuberculin skin test is the best diagnostic method to detect tuberculous infection. How accurate is interpretation of the test?

DESIGN

Observational study.

SETTING

Both general hospital and university hospital.

PARTICIPANTS

One hundred seven health-care professionals, including 52 practicing pediatricians, 33 pediatric house officers, 10 pediatric academicians, 11 registered nurses, and 1 pediatric nurse practitioner.

STUDY

A tuberculin skin test (Mantoux) was applied to the arm of a known tuberculin converter. As participants entered/left the room, they were guided to the tuberculin converter. At no time did a participant observe readings other than his/her own.

RESULTS

Mantoux tuberculin reaction measuring 15 mm induration was read individually by a group of 52 practicing pediatricians, 33 pediatric house officers, 10 pediatric academicians, 11 registered nurses, and one pediatric nurse practitioner. The median induration recorded by this group of 107 health-care professionals was 10 mm, and 17 (33%) practicing pediatricians read the reaction as <10 mm induration. Using the > or = 15-mm induration indicator to identify a positive reaction, 93% of those in the study (99/107 participants) would have identified our known converter as tuberculin negative.

CONCLUSION

This study confirms a general inaccuracy in interpretation of the tuberculin skin test reaction. It raises two questions. (1) Is there a general tendency toward underreading? (2) Does this general tendency to underread tuberculin skin test reactions raise some question as to the American Academy of Pediatrics, American Thoracic Society, and Centers for Disease Control and Prevention move in raising the amount of induration considered tuberculin positive to 15 mm in low-risk individuals?

Friendships, peer acceptance, and group membership: relations to academic achievement in middle school

Two samples of sixth-grade students were followed over time to examine relations of number of reciprocated friendships, peer acceptance, and group membership to academic achievement. In both samples, group membership was the most consistent predictor of grades over time. In Study 2, prosocial behavior, antisocial behavior, and emotional distress were examined as processes that might explain these significant links between peer relationships and academic achievement. Results of longitudinal analyses support a conclusion that aspects of peer relationships are related to classroom achievement indirectly, by way of significant relations with prosocial behavior. Future research might benefit from more in-depth analyses of the functions of adolescent peer relationships and the processes by which they influence orientations toward social and academic competence at school.

punt and schnurri regulate a somatically derived signal that restricts proliferation of committed progenitors in the germline

To identify regulators of stem cell lineages, we are focusing on spermatogenesis in Drosophila. In spermatogenesis, each germline stem cell divides asymmetrically, renewing itself and producing a transiently amplifying daughter, which divides four times. By screening for mutants in which daughter cells fail to stop dividing, we find that the TGF-beta signal transducers schnurri and punt are required to limit transient amplification of germ cells. Mosaic analysis demonstrates that punt and schnurri act within somatic cyst cells that surround germ cells, rather than in germ cells. Thus, a cyst-cell-derived signal restricts germ cell proliferation and this signal is initiated by input from a member of the TGF-beta superfamily. Thus, a signal relay regulates progression through the germline stem cell lineage.

Ideological influences on curriculum development in nurse education

The development of curricula in nurse education cannot be viewed in isolation from the socio-political context within which it exists. Changes in the prevailing political ideology have impacted on the social life of individuals, and the reflection of this can be traced in the curricula of nursing courses over time. To ensure that courses meet the needs of both students and society, it is important for teachers to recognize the influence of the context within which such development takes place, and to understand the ideological underpinning of that which is being both taught and learnt. It is only with adequate understanding that challenges can be presented and change promoted when necessary.

Comparative study of human red blood cell analysis with three different field-flow fractionation systems

An extensive multi-laboratory study was conducted to compare three different field-flow fractionation (FFF) systems for use in the analysis of human erythrocytes. The object of this study was to determine the relationship between the FFF elution properties for each system and the traditional hematological blood cell parameters. One centrifugal system (Utah) and two gravitational systems (Paris and Abbott) were compared. In order to analyze erythrocyte populations with a broad range of hematological indices, blood samples were collected from individuals heterozygous for sickle cell anemia (A/S) and also from normal controls (A/A), and these were analyzed at each site. Identical samples were analyzed by the Abbott and Utah sites. With all three systems, blood samples from each category produced narrow, overlapping distributions of FFF retention ratios, with the Abbott and Utah systems showing slight elevations in the mean retention ratios for the sickle cell samples. Blood cell elution peak characteristics were compared with standard hematological parameters for each of the FFF systems, and negative correlations were consistently found between mean corpuscular volume (MCV) and retention ratios. Positive correlations were found between red cell distribution width (RDW) and retention ratios. Elevated FFF retention ratios were frequently found with blood samples having abnormal hematological profiles. These results demonstrate that the three differently configured systems all produce similar analysis profiles for erythrocytes from the classes studied here. The relationships between FFF parameters and hematological indices were consistent for all systems.

Subclass distribution of maternal and neonatal anti-Ro(SSA) and La(SSB) antibodies in congenital heart block

OBJECTIVE

To compare the subclass distribution of anti-48 kDa La(SSB) and anti-52 and 60 kDa Ro(SSA) antibodies in the maternal and neonatal circulation, in pregnancies affected and unaffected by the development of congenital heart block (CHB).

METHODS

Sera were obtained from 32 mothers (during 34 pregnancies 23 complicated by CHB and 11 healthy) demonstrated to have anti-Ro(SSA) and/or La(SSB). Maternal and neonatal autoantibodies were evaluated for subclass distribution by ELISA:

RESULTS

All 4 subclasses of anti-Ro(SSA) and La(SSB) antibodies cross the placenta and are detectable in sera obtained from the umbilical cord, IgG1 and IgG3 were the major subclasses represented in the 48 kDa La(SSB) and 52 kDa Ro(SSA) responses. All subclasses, including IgG2 and IgG4, were observed in about one-third of the anti-52 kDa Ro(SSA) and 48 kDa La(SSB) responses. In contrast, anti-60 kDa antibodies were, with rare exception, confined to IgG1. Except for anti-48 kDa La(SSB) IgG3 antibodies, no significant differences were observed between affected and unaffected pregnancies in the ratio of maternal to neonatal levels of any of the antibody subclasses. Overall, there were no significant differences in the subclass profiles between mothers whose children had heart block and those who did not.

CONCLUSION

The IgG subclasses of anti-48 kDa La(SSB) and anti-52 and 60 kDa Ro(SSA) do not account for the susceptibility of one fetus versus another for the development of CHB. Anti-60 kDa Ro(SSA) antibodies are more restricted in subclass distribution than anti-52 kDA Ro(SSA) or 48 kDa La(SSB) responses.

Homosexuality: a neglected issue in stoma care

Problems of living with an altered body image following stoma surgery have long been recognised, but the specific needs of homosexual patients undergoing such surgery have been largely disregarded. This article examines the ways in which nurses can support their homosexual stoma clients.

The dexamethasone suppression test and the diagnosis of depression in adults with severe and profound developmental disabilities

The dexamethasone suppression test (DST) was administered to 40 adults with severe and profound mental retardation. All participants were free from known conditions which may have given misleading results from cortisol assay. Of nine participants who showed symptoms possibly indicating depression the DST results concurred in two cases (i.e. there were two true-positives). However there were four or five (depending on criteria adopted) false-positive DST results. There did not appear to be a consistent behavioural profile for positive DST responders. With sensitivity to possible depression estimated at 22%, and a diagnostic confidence of < 35%, these data do not support recommendations that the DST is useful for assisting in diagnosis of depression in this population.

Relationship between maternal and neonatal levels of antibodies to 48 kDa SSB(La), 52 kDa SSA(Ro), and 60 kDa SSA(Ro) in pregnancies complicated by congenital heart block

OBJECTIVE

Since there is suggestive but, to date, indirect evidence that maternal anti-SSA(Ro) and SSB(La) antibodies are pathogenic in congenital heart block (CHB), we explored the hypothesis that binding to fetal tissues would result in selective depletion of autoantibodies from the neonatal circulation.

METHODS

Maternal and umbilical cord levels of anti-48 kDa SSB(La), anti-52 kDa SSA(Ro) and anti-60 kDa SSA(Ro) antibodies were measured by ELISA and immunoprecipitation at parturition in 15 pregnancies complicated by CHB. A control group consisted of 13 pregnancies in which the mother was known to have antibodies to either SSA(Ro) and/or SSB(La) and the children did not have CHB.

RESULTS

The ratios of maternal to cord serum levels of anti-48 SSB(La), anti-52 SSA(Ro) and anti-60 kDa SSA(Ro) antibodies ranged from 0.71 to 2.38 in both affected and unaffected pregnancies. The mean ratio obtained for each of the 3 autoantibodies was not significantly different between the 2 groups. Moreover these ratios did not significantly differ from the mean ratios obtained for total IgG levels in either group.

CONCLUSION

These data demonstrate that maternal antibodies to all components of the SSA(Ro) SSB(La) system are efficiently transported across the placenta and are not selectively depleted in the circulation of neonates with CHB.

Disruption of the posterior pelvic ring caused by vertical shear

Disruption of the posterior pelvic ring caused by vertical shearing forces is associated with significant morbidity and mortality. We reviewed the intermediate results in 18 patients who had 20 disruptions of the posterior pelvic ring. Depending on the location of the injury, patients were treated by either skeletal traction or open reduction and internal fixation. Patients who had open reduction and internal fixation had a significantly shorter hospitalization, a shorter confinement to bed, a shorter time to full weight-bearing, and fewer early complications. In addition, on intermediate follow-up, these patients had less back and leg pain and fewer gait disturbances, and were more likely to be able to do heavy work. Further study is needed to determine whether these results will be preserved on long-term follow-up.

Methanol levels in methylated spirit drinking alcoholics

On three different occasions, blood samples sent to this laboratory from the accident and emergency department were found to contain potentially toxic amounts of methanol (30, 34 and 41 mmol/l) during analysis for ethanol by a gas chromatographic method. It is suggested that the simultaneous determination of both alcohols may be clinically important in methylated spirit drinking alcoholics.

Purified membrane fractions from mammary tumor cells elicit biological reactivity in in vitro cell-mediated immune reactions

Lithium chloride (LiCl) aggregation followed by centrifugation through a sucrose step gradient was used to obtain purified plasma membranes from two sublines of mouse mammary adenocarcinoma. These two tumor lines were chemically induced by treatment of a hyperplastic nodule with 7,12-dimethylbenzanthracene (DMBA). One line, D1-DMBA-3, has been found to be immunogenic to the host of origin, while the other, D1-DMBA-2, does not elicit specific tumor immunity as previously tested in in vivo and in vitro immune reactions. The purified membrane fractions were assayed for protein, DNA and sialic acid content as well as enzymatic markers of membrane purity. When tested in blastogenesis and cytotoxicity reactions, membrane-containing fractions from the D1-DMBA-3 immunogenic tumor were found to be stimulatory to spleen cells of D1-DMBA-3 tumor bearers over a ten-fold protein concentration. Spleen cells from normal mice do not respond in these reactions to the various tumor fractions. No reactivity was observed when non-membrane-containing preparations were used as stimuli in the cell-mediated immune reactions. The specificity of these reactivities was further demonstrated by the lack of responses when fractions from the non-immunogenic D1-DMBA-2 tumor were tested in parallel in our in vitro assays. The data presented indicate that the procedure employed is useful for the isolation of membrane-associated, tumor-specific antigens which can be easily quantitated and still retain biological activity in in vitro tests of cell-mediated immunity.