Effects of a physiotherapist-led stroke training programme for nurses

AIM

to assess the effects of a physiotherapist-led stroke training programme for nurses working in a rehabilitation ward on clinical practice and patient outcome.

METHOD

before and after group comparison with outcome assessment by observational and quantitative methods. Non-participant observation before and after the 5-month training programme recorded patient position, transfers and contact with nursing staff. Quantitative assessments of disability, satisfaction and mood were made at baseline, discharge and 4 months after stroke onset. We also noted selected stroke complications, rehabilitation ward length of stay and discharge destination.

RESULTS

there was a significant improvement in the number of observed 'good' transfers of patients undertaken by nurses (chi2 = 9.13, df = 1, P = 0.003) but the training programme had no impact on the time the patients spent in 'poor' positions. There was no significant difference between the two groups for Barthel index scores at discharge and at 4 months. Neither was there any significant difference in the Hospital Anxiety and Depression scale, occurrence of secondary complications, length of stay or the Patient and Carer Satisfaction Questionnaires.

CONCLUSION

within the limitations of the research design adopted, some improvements in clinical practice were reported but there were no significant differences in patient outcome. The training programme required no additional resources and should be replicable in most district general hospitals.

ED use of flexion-extension cervical spine radiography in the evaluation of blunt trauma

Dynamic cervical spine radiography (CSR) is used to detect ligamentous instability. We investigated the ED use of dynamic CSR through a retrospective descriptive review using a convenience sample study design at a university emergency department. Adult blunt trauma patients with static (lateral, AP, odontoid) and dynamic (flex, extend) CSR participated. 451 patients (52% male with mean age of 33.6 years) met entry criteria. Injury mechanisms were 74% MVA, 12% fall, 8% direct trauma, and 6% other. Indications for dynamic CSR were 100% traumatic mechanism, 86% neck pain, 70% midline neck tenderness, and 18% abnormal static CSR. Static CSR were normal in 372, 5 of which had abnormal dynamic CSR (5 cervical contour line disruption [CCLD], 2 posterior element abnormality [PEA]); of these 5 patients, none required invasive stabilization. Static CSR were abnormal in 79 patients (38 CCLD, 30 lordotic curve reversal, 17 PEA, 4 soft tissue swelling) of which 16 had abnormal dynamic CSR (9 increased CCLD, 4 PEA, and 4 fracture); of these 16 patients, 4 required invasive stabilization. Final diagnoses were 428 cervical soft tissue injury, 11 subluxation, 8 fracture, 2 fracture-subluxation, and 2 spinal cord injury without radiographic abnormality. Spine consultation was made in 12%. Stabilization therapy was required: 21 soft collar, 4 surgical, 3 halo-device, and 5 other. No complications of dynamic CSR were noted. The blunt trauma patient with neck complaints and an abnormal static CSR was more likely to have an abnormal dynamic CSR demonstrating a cervical injury requiring stabilization compared to patients with normal static CSR.

Comparison of candesartan, enalapril, and their combination in congestive heart failure: randomized evaluation of strategies for left ventricular dysfunction (RESOLVD) pilot study. The RESOLVD Pilot Study Investigators

BACKGROUND

We investigated the effects of candesartan (an angiotensin II antagonist) alone, enalapril alone, and their combination on exercise tolerance, ventricular function, quality of life (QOL), neurohormone levels, and tolerability in congestive heart failure (CHF).

METHODS AND RESULTS

Seven hundred sixty-eight patients in New York Heart Association functional class (NYHA-FC) II to IV with ejection fraction (EF) <0.40 and a 6-minute walk distance (6MWD) <500 m received either candesartan (4, 8, or 16 mg), candesartan (4 or 8 mg) plus 20 mg of enalapril, or 20 mg of enalapril for 43 weeks. There were no differences among groups with regard to 6MWD, NYHA-FC, or QOL. EF increased (P=NS) more with candesartan-plus-enalapril therapy (0.025+/-0.004) than with candesartan alone (0.015+/-0.004) or enalapril alone(0.015+/-0.005). End-diastolic (EDV) and end-systolic (ESV) volumes increased less with combination therapy (EDV 8+/-4 mL; ESV 1+/-4 mL; P<0.01) than with candesartan alone (EDV 27+/-4 mL; ESV 18+/-3 mL) or enalapril alone (EDV 23+/-7 mL; ESV 14+/-6 mL). Blood pressure decreased with combination therapy (6+/-1/4+/-1 mm Hg) compared with candesartan or enalapril alone (P<0.05). Aldosterone decreased (P<0.05) with combination therapy (23.2+/-5.3 pg/mL) at 17 but not 43 weeks compared with candesartan (0.7+/-7.8 pg/mL) or enalapril (-0.8+/-11. 3 pg/mL). Brain natriuretic peptide decreased with combination therapy (5.8+/-2.7 pmol/L; P<0.01) compared with candesartan (4. 4+/-3.8 pmol/L) and enalapril alone (4.0+/-5.0 pmol/L).

CONCLUSIONS

Candesartan alone was as effective, safe, and tolerable as enalapril. The combination of candesartan and enalapril was more beneficial for preventing left ventricular remodeling than either candesartan or enalapril alone.

Endoscopic skull base surgery I: a new animal model for pituitary surgery

Endoscopy has emerged as a new means to perform minimally invasive surgery of the skull base. Specifically, endoscopic techniques and instruments can be used to safely and effectively approach and resect tumors of the pituitary gland in humans. No animal model currently exists to serve as a template upon which to refine and develop endoscopic surgical technique in this region of the anatomy. We operated on two purpose-bred Hampshire-Yorkshire-Duroc hybrid swine to demonstrate the application of endoscopy to pituitary surgery. Based upon similar anatomical relationships in humans and swine between the oropharynx, nasopharynx, and skull base, we used a transoral, transpalatal approach to access the vomer of the swine. Under endoscopic exposure, we resected the vomer, entered the sphenoid sinus, and then resected the sphenoid septum, sella turcica, and adenohypophysis. Clear visualization of the pituitary, hypophyseal stalk, cavernous sinuses, and carotid prominences was achieved and documented with digital photography. Benefits and limitations of the technique were noted. These results have pertinent implications both for the study of the surgical anatomy of the swine craniofacial skeleton, and for future development of endoscopic surgical manipulation of the skull base.

Lung volume reduction surgery (LVRS) for chronic obstructive pulmonary disease (COPD) with underlying severe emphysema

BACKGROUND

Lung volume reduction surgery (LVRS) has recently re-emerged as a surgical option for the treatment of end stage chronic obstructive pulmonary disease (COPD) due to underlying severe emphysema. Advocates of LVRS claim that it represents a significant breakthrough in the management of this challenging group of patients while sceptics point to uncertainty about the effectiveness of the operation.

METHODS

A systematic review was conducted of the evidence on the effects of LVRS in patients with end stage COPD secondary to severe emphysema.

RESULTS

The most rigorous evidence on the effectiveness of LVRS came from case series. Seventy five potentially relevant studies were identified and 19 individual series met the methodological criteria for inclusion. The pattern of results was consistent across individual studies despite a significant degree of clinical heterogeneity. Significant short term benefits occurred across a range of outcomes which appeared to continue into the longer term. Physiological improvements were matched by functional and subjective improvements. Early mortality rates were low and late mortality rates compared favourably with those of the general COPD population. However, the entire research base for the intervention is subject to the limitations of study designs without parallel control groups.

CONCLUSIONS

LVRS appears to represent a promising option in the management of patients with severe end stage emphysema. However, until the results of ongoing clinical trials are available, the considerable uncertainty that exists around the effectiveness and cost effectiveness of the procedure will remain.

Screening SMAD1, SMAD2, SMAD3, and SMAD5 for germline mutations in juvenile polyposis syndrome

BACKGROUND AND AIMS

Juvenile polyps occur in several Mendelian disorders, whether in association with gastrointestinal cancer alone (juvenile polyposis syndrome, JPS) or as part of known syndromes (Cowden, Gorlin, and Bannayan-Zonana) in association with developmental abnormalities, dysmorphic features, or extraintestinal tumours. Recently, some JPS families were shown to harbour germline mutations in the SMAD4 (DPC4) gene, providing further evidence for the importance of the TGFbeta signalling pathway in colorectal cancer. There remains, however, considerable, unexplained genetic heterogeneity in JPS. Other members of the SMAD family are excellent candidates for JPS, especially SMAD2 (which, like SMAD4, is mutated somatically in colorectal cancers), SMAD3 (which causes colorectal cancer when "knocked out" in mice), SMAD5, and SMAD1.

METHODS

SMAD1, SMAD2, SMAD3, and SMAD5 were screened for germline mutations in 30 patients with JPS and without SMAD4 mutations.

RESULTS

No mutations were found in any of these genes. A G-A C89Y polymorphism with possible effects on protein function was found in SMAD3, but the frequencies of the G and A alleles did not differ between patients with JPS and controls.

CONCLUSIONS

It remains to be determined whether or not this polymorphism is involved in a minor predisposition to colorectal or other carcinomas. SMAD4 may be the only member of the SMAD family which causes JPS when mutant in the germline. The other genes underlying JPS remain to be identified.

Sequence-tagged connectors: a sequence approach to mapping and scanning the human genome

The sequence-tagged connector (STC) strategy proposes to generate sequence tags densely scattered (every 3.3 kilobases) across the human genome by arraying 450,000 bacterial artificial chromosomes (BACs) with randomly cleaved inserts, sequencing both ends of each, and preparing a restriction enzyme fingerprint of each. The STC resource, containing end sequences, fingerprints, and arrayed BACs, creates a map where the interrelationships of the individual BAC clones are resolved through their STCs as overlapping BAC clones are sequenced. Once a seed or initiation BAC clone is sequenced, the minimum overlapping 5' and 3' BAC clones can be identified computationally and sequenced. By reiterating this "sequence-then-map by computer analysis against the STC database" strategy, a minimum tiling path of clones can be sequenced at a rate that is primarily limited by the sequencing throughput of individual genome centers. As of February 1999, we had deposited, together with The Institute for Genomic Research (TIGR), into GenBank 314,000 STCs ( approximately 135 megabases), or 4.5% of human genomic DNA. This genome survey reveals numerous genes, genome-wide repeats, simple sequence repeats (potential genetic markers), and CpG islands (potential gene initiation sites). It also illustrates the power of the STC strategy for creating minimum tiling paths of BAC clones for large-scale genomic sequencing. Because the STC resource permits the easy integration of genetic, physical, gene, and sequence maps for chromosomes, it will be a powerful tool for the initial analysis of the human genome and other complex genomes.

Block of (Na+,K+)ATPase with ouabain induces spreading depression-like depolarization in hippocampal slices

We used ouabain (100 microM) to block Na+,K(+)ATPase of in vitro rat hippocampal slices. This treatment was sufficient to cause the sudden depolarization that is the hallmark of both spreading depression (SD) and of the SD-like anoxic depolarization (AD). This depolarization was accompanied by a large and sudden increase in [K](o), also reminiscent of that observed during both SD and AD. Ouabain-induced SD did not require a complete inactivation of Na+,K(+)ATPase, as it occurred when the enzyme was still capable of providing recovery of both V(o) and [K](o). The data indicate that functional inactivation of Na+,K(+)ATPase per se initiates events that lead to an SD-like AD. This ouabain-induced depolarization was not affected by block of synaptic transmission, instead it was abolished by hyperosmolarity of the extracellular space. The possible relevance of these findings to the pathophysiology of AD is discussed.

Antimüllerian hormone in patients with hypogonadotropic hypogonadism

Antimullerian hormone (AMH) is produced by immature Sertoli cells until pubertal maturation. At puberty, elevation of serum testosterone correlates with a decrease in serum AMH. To further investigate the hormonal control of AMH secretion, serum AMH levels were measured in 20 normal men (20-60 yr), in 12 patients (19-30 yr) with congenital hypogonadotropic hypogonadism (CHH), and in 18 patients (19-65 yr) with acquired hypogonadotropic hypogonadism (AHH) either untreated or during testosterone or human chorionic gonadotropin (hCG) therapy. Mean serum AMH levels in normal adult men were low (20+/-4.9 pmol/L). In untreated CHH patients, mean serum AMH levels were significantly higher than in normal men (292+/-86 pmol/L, P < 0.001) and were similar to those previously reported in prepubertal boys. In men with AHH, mean serum AMH levels were also significantly increased (107+/-50 pmol/L; P < 0.01) when compared with healthy men but were less than in men with CHH. In addition, in 10 patients treated for prostate cancer, a modest but significant increase of serum AMH (from 11.4 +/-5.7 pmol/L to 49+/-9.9 pmol/L; P < 0.01) was observed 12 months after suppression of the gonadal axis with the GnRH agonist Triptorelin (3.75 mg IM once a month). Plasma testosterone (T) and serum AMH levels were measured at baseline and at 3 and 6 months in 10 HH patients (6 CHH and 4 AHH) treated with hCG (1500 IU/twice weekly for 6 months) and in 8 HH (4 CHH and 4 AHH) patients treated with T (T enanthate 250 mg/3 weeks for 6 months). hCG treatment induced an increase of plasma T (from 1.0+/-0.7 to 11+/-2.4 and 19+/-4.8 nmol/L, at 3 and 6 months respectively) associated with a dramatic decrease of serum AMH (from 314+/-93 to 56+/-30 and 17+/-4.3 pmol/L). The similar increase in plasma T levels (from 1.4+/-1.0 to 15.6+/-4.2 and 23+/-6.2 ng/mL) obtained with exogenous T induced a lesser decrease of serum AMH (from 221+/-107 pmol/L to 114+/-50 and 66+/-17 pmol/L, at 3 and 6 months respectively). In conclusion, high plasma AMH levels in CHH patients are related to the absence of pubertal maturation of Sertoli cells. The high AMH levels in AHH and its increase after Triptorelin-induced gonadotropin deficiency suggest that the suppression of AMH is a reversible phenomenon. Finally, the inhibition of AMH production by Sertoli cells is induced by intratesticular T.

Recovering from stroke: a qualitative investigation of the role of goal setting in late stroke recovery

This article examines the role of goal setting in the continuing relationship between specialist nurse and patients recovering from stroke. The nurse intervention was intended to ease the patient through the stages of recovery from stroke, focusing on emotional and social recovery rather than physical function. Literature on the use of goals in the nursing process is discussed. The article uses data from contemporary nurse records and from interviews with nurses and with patients and caregivers. The data from each of these elements were subjected to content analysis and were then synthesized using a grounded theory approach to interpret their significance. The perspective of patients and caregivers provides an additional insight into the use and limitations of goal setting which is largely developed in the literature from a nursing perspective. Nurses were found to have different interpretations of the use of goal setting. Some used it explicitly in their relationships with patients, whilst others used the concept to inform their actions whilst being less explicit and more informal. In all cases they demonstrate the tension between establishing and supporting progress towards realistic recovery goals and recognizing the limitations now placed on stroke victims.

Infrequent loss of heterozygosity of APC/MCC and DCC genes in gastric cancer showing DNA microsatellite instability

AIM

To investigate the role of DNA microsatellite instability (MSI) in gastric carcinogenesis by studying associations between MSI status, clinicopathological features, and loss of genetic loci.

METHODS

Six microsatellite loci and loss of heterozygosity at APC, DCC, and MCC were analysed by polymerase chain reaction based methods in 53 cases of advanced gastric cancer.

RESULTS

MSI was observed in 32.1% of gastric carcinomas (17/53) and 20% of foci of intestinal metaplasia (3/15). Seven gastric carcinomas (13.7%) were MSI-high (MSI-H) (three loci or more) and 10 (18.9%) were MSI-low (MSI-L) (one or two loci). The frequency of MSI-H was higher in intestinal (25.0%) than in diffuse carcinomas (3.7%) (p < 0.05). None of the MSI-H tumours showed loss of heterozygosity at APC, MCC, or DCC loci.

CONCLUSIONS

MSI may have an important and early role in a subset of gastric cancers, particularly the intestinal type. The MSI-H subset of gastric cancer has features in common with its colorectal counterpart, whereas MSI-L and microsatellite stable cancers appear to develop through the loss of heterozygosity pathway.

[Diagnosis and treatment of hypogonadotropism in males and females]

Hypogonadotropic hypogonadism is the consequence of FSH and LH deficiency leading to testicular or ovarian dysfunction. The diagnosis should be considered when there is a complete absence of pubertal development in both sexes. Hypogonadotropism, that occurs after puberty, is revealed by secondary amenorrhea in women, decreased libido in men. The hormonal diagnosis is easy in the complete forms with usually undetectable plasma LH, FSH and sex steroid levels. In the partial forms, plasma gonadotropin levels may be in the low normal range with slightly decreased plasma sex steroid levels. Gonadotropin deficiency may be isolated, congenital and of genetic origin. In acquired forms, panhypopituitarism and mass lesions of the hypothalamic pituitary sites must be diagnosed by magnetic resonance imaging and hormonal testing. Treatment requires only substitution when fertility is not sought. In the treatment of infertility, the use of pulsatile modes of GnRH administration is remarkably successful in women, as well as exogenous gonadotropins in both sexes.

Characterisation of a subtype of colorectal cancer combining features of the suppressor and mild mutator pathways

BACKGROUND

10% of sporadic colorectal cancers are characterised by a low level of microsatellite instability (MSI-L). These are not thought to differ substantially from microsatelite-stable (MSS) cancers, but MSI-L and MSS cancers are distinguished clinicopathologically and in their spectrum of genetic alterations from cancers showing high level microsatellite instability (MSI-H).

AIMS

To study the distribution of molecular alterations in a series of colorectal cancers stratified by DNA microsatellite instability.

METHODS

A subset of an unselected series of colorectal cancers was grouped by the finding of DNA MSI at 0 loci (MSS) (n = 51), 1-2 loci (MSI-L) (n = 38) and 3-6 loci (MSI-H) (n = 25). The frequency of K-ras mutation, loss of heterozygosity (LOH) at 5q, 17p and 18q, and patterns of p53 and beta catenin immunohistochemistry was determined in the three groups.

RESULTS

MSI-H cancers had a low frequency of K-ras mutation (7%), LOH on chromosomes 5q (0%), 17p (0%) and 18q (12.5%), and a normal pattern of immunostaining for p53 and beta catenin. MSI-L cancers differed from MSS cancers in terms of a higher frequency of K-ras mutation (54% v 27%) (p = 0.01) and lower frequency of 5q LOH (23% v 48%) (p = 0.047). Whereas aberrant beta catenin expression and 5q LOH were concordant (both present or both absent) in 57% of MSS cancers, concordance was observed in only 20% of MSI-L cancers (p = 0.01).

CONCLUSIONS

MSI-L colorectal cancers are distinct from both MSI-H and MSS cancers. This subset combines features of the suppressor and mutator pathways, may be more dependent on K-ras than on the APC gene in the early stages of neoplastic evolution, and a proportion may be related histogenetically to the serrated (hyperplastic) polyp.

Two years' prospective experience using fluorescence in situ hybridization on uncultured amniotic fluid cells for rapid prenatal diagnosis of common chromosomal aneuploidies

A probe was generated from the YAC clone 831B9 that was suitable for the prenatal detection of trisomy 21 using fluorescence in situ hybridization (FISH). This probe was initially tested on a series of 650 unselected amniotic fluid samples prior to the karyotype being available. 630 were correctly identified as having two copies and 13 samples were correctly scored as having three copies of chromosome 21. Seven samples failed to produce a result. A trial was then initiated, reporting to clinicians the interphase FISH results before cytogenetic analysis had been performed. During the first 18 months of this trial 1504 samples were tested: 1467 were correctly identified as disomic and 35 samples were correctly scored as trisomic for chromosome 21. Two samples failed to produce a result. A chromosome 18 specific probe (LI.84) was employed where there was a relevant clinical indication (181 samples) and 10 samples were correctly scored as having three copies of chromosome 18. Thus, this approach appears to be reliable and is popular with both clinicians and patients due to the speed of the result. However, it does not replace chromosomal analysis on cultured cells, which detected a range of abnormalities besides the trisomies and triploidies detected by FISH.

Patient satisfaction with nursing care: a measurement conundrum

Patient satisfaction is a major indicator of quality care. There are several theories on the types of concepts that should be measured concerning patient satisfaction with nursing care. Given the different theories of patient satisfaction, the issue of accurate measurement of this concept presents nurse researchers, clinicians and leaders with a challenge. This paper will discuss the findings of a patient satisfaction survey that was conducted in two acute care surgical wards, using the revised 28-item La Monica-Oberst patient satisfaction scale and telephone interviews. Data were analysed using descriptive statistics. Textual data were managed using NUD*IST and analysed for common emerging themes and categories. The findings of the quantitative and qualitative data were compared in order to determine similarities and differences. The survey results revealed very high levels of patient satisfaction; however, the qualitative data revealed some anomalies. Specifically, due to the numbers of nurses involved in the care, some patients had difficulties answering the questionnaire. Moreover, they were unable to discriminate nursing care from the rest of their overall patient experience. Within this study, it seemed that patients' perceptions of nurses influenced the way patients rated quality nursing care. Based on this information, the authors question the accuracy of the measurement of patient satisfaction and raise issues that need to be considered in order to further clarify the measurement of this concept.

[Lacrimal gland hypertrophy: revealing sarcoidosis]

We present a case of systemic sarcoidosis in a 34-year-old woman initially presenting with bilateral and symmetric proptosis caused by lacrimal gland enlargement. Based upon clinical, biological and radiological findings, sarcoidosis was suspected with lacrymal gland, parotid and pulmonary lesions. Biopsy of enlarged lacrimal gland for histological examination revealed a non caseating granuloma compatible with the diagnosis of sarcoidosis. Sarcoid lesions regressed with corticosteroid therapy.

Improving the repeat prescribing process in a busy general practice. A study using continuous quality improvement methodology

PROBLEM

A need to improve service to patients by reducing the time wasted by reception staff so that the 48 hour target for processing repeat prescription requests for patient collection could be achieved.

DESIGN

An interprofessional team was established within the practice to tackle the area of repeat prescribing which had been identified as a priority by practice reception staff. The team met four times in three months and used continuous quality improvement (CQI) methodology (including the Plan-Do-Study-Act cycle) with the assistance of an external facilitator.

BACKGROUND AND SETTING

A seven partner practice serving the 14,000 patients on the northern outskirts of Bournemouth including a large council estate and a substantial student population from Bournemouth University. The repeat prescribing process is computerised.

KEY MEASURES FOR IMPROVEMENT

Reducing turn around times for repeat prescription requests. Reducing numbers of requests which need medical records to be checked to issue the script. Feedback to staff about the working of the process.

STRATEGIES FOR CHANGE

Using a Plan-Do-Study-Act cycle for guidance, the team decided to (a) coincide repeat medications and to record on the computer drugs prescribed during visits; (b) give signing of prescriptions a higher priority and bring them to doctors' desks at an agreed time; and (c) move the site for printing prescriptions to the reception desk so as to facilitate face to face queries.

EFFECTS OF CHANGE

Prescription turnaround within 48 hours increased from 95% to 99% with reduced variability case to case and at a reduced cost. The number of prescriptions needing records to be looked at was reduced from 18% to 8.6%. This saved at least one working day of receptionist time each month. Feedback from all staff within the practice indicated greatly increased satisfaction with the newly designed process.

LESSONS LEARNT

The team's experience suggests that a combination of audit and improvement methodology offers a powerful way to learn about, and improve, practice. The interventions used by the team not only produced measurable and sustainable improvements but also helped the team to learn about the cost of achieving the results and provided them with tools to accomplish the aims. The importance of feedback to all staff about CQI measures was also recognised.

Otoacoustic emission criteria for neonatal hearing screening

Transient evoked otoacoustic emission measures are gaining acceptance as a technique in new-born hearing screening. At present a wide variety of pass-fail screening criteria are used in otoacoustic emission screening programs. In a study of 100 special care neonates and 35 well, full term babies, a number of screening criteria were examined for sensitivity and specificity characteristics when compared to a standard auditory brainstem response protocol. Results indicate that, for normal and special care neonates with a gestational age at test of 38-41 weeks, high sensitivity ( > 80%) could be obtained when a pass-fail criterion involving analysis of emission reproducibility, or emission reproducibility and emission response level, was set. Sensitivity was reduced for special care neonates who fell outside this age range. Specificity was found to be relatively low overall (always < 65%) and may relate to clinical factors in special care neonates not investigated in this study.

Influence of phospholipid composition on the properties of reconstituted surfactants

The influence of phospholipids on the ultrastructure and metabolism of reconstituted surfactants has not been well defined. The aim of this study was to determine if changes in the phospholipid composition of reconstituted surfactants altered their biophysical properties, ultrastructure, and conversion to light subtype by cycling. We prepared various surfactants containing radiolabeled dipalmitoylphosphatidylcholine ([14C]DPPC). The addition of phosphatidylglycerol (PG) or dipalmitoylphosphatidic acid (PA) to DPPC increased conversion to light subtype. In contrast, the addition of dipalmitoylphosphatidylglycerol (DPPG) to DPPC markedly reduced conversion to light subtype on cycling. DPPC and DPPC+PG produced large liposomes ( approximately 1,000 nm), whereas DPPC+PA or DPPC+DPPG formed multilamellar membranes. Mixtures of DPPC and PA were highly surface active in vitro, whereas the surface activity of DPPC+DPPG was similar to that of DPPC. In conclusion, the ultrastructure, metabolism, and surface active properties of DPPC+PG mixtures were influenced markedly by alterations in the fatty acid composition or polar head group of PG.