Nebulized Versus Intravenously Administered Dexmedetomidine for Obtunding Hemodynamic Responses to Laryngoscopy and Tracheal Intubation: A Randomized Double-Blind Comparative Study

Introduction Intravenous dexmedetomidine is known to cause major adverse effects such as bradycardia, hypotension, cardiac arrhythmias, and heart block when used as premedication for attenuation of the laryngoscopy and intubation response, limiting its routine use. Thus, it is important to study other routes of administration of dexmedetomidine. Objectives To compare the hemodynamic response and sedation score between intravenous and nebulized dexmedetomidine as premedication for the attenuation of the laryngoscopy and intubation response. Materials and methods In this study, 60 patients fulfilling inclusion criteria undergoing surgeries under general anesthesia (ASA Grade I and II) were randomly allocated into two groups of 30 patients each. Group IV received intravenous 1 mcg/kg dexmedetomidine in 100 mL normal saline, and Group IN received nebulization with 1 mcg/kg dexmedetomidine diluted to a total volume of 5 cc of normal saline, 30 minutes prior to the induction of general anesthesia. Sedation scores were calculated using the Ramsay sedation score at 20 minutes after the administration of the drug; patients were induced by the standard protocol, and laryngoscopy was performed. Vitals were recorded before the administration of the drug and after intubation at stipulated time intervals. Results The median heart rate becomes significantly lower at 15 minutes (70 vs. 76.5) and 20 minutes (66 vs. 76) after induction among Group IV as compared to Group IN. The median systolic blood pressure was significantly lower at 20 minutes in Group IV (110 mmHg) than in Group IN (119 mmHg). The median diastolic blood pressure was significantly lower at 10 minutes (76 vs. 79), 15 minutes (70 vs. 77), and 20 minutes (69 vs. 78.5) in Group IV than in Group IN. The median of mean arterial pressure was significantly lower at 15 minutes (84.8 vs. 91.5) and 20 minutes (83 vs. 92) in Group IV than in Group IN. A comparison of vitals after induction shows that the median heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure were significantly lower statistically among Group IV as compared to Group IN at 0, 1, 3, 5, 10, 15, and 30 minutes after induction (except for systolic blood pressure at 3 minutes). The median sedation score was lower in Group IN (0) than in Group IV (1); this difference is statistically significant. Conclusion The obtundation of hemodynamic responses following laryngoscopy and maintaining hemodynamics intraoperatively is statistically better with nebulized dexmedetomidine compared to intravenous dexmedetomidine.

POS1546-HPR DISEASE ACTIVITY BURDEN FOR LONG TERM RHEUMATOLOGY FOLLOW-UP PATIENTS

Background

There has been a lot of emphasis for early diagnosis and treatment for immune mediated rheumatology conditions such as Treat to target (T2T) for inflammatory arthritis, Fast track pathway for Giant cell arteritis. However, the data regarding burden of disease activity, nature and proportion of long term rheumatology follow up patients in rheumatology clinics have not been explored. There are conditions which are refractory to treatment or affected by recurrent flare-ups requiring long term follow-ups and constant monitoring. With increasing life expectancy and better treatment of the long term conditions, emphasis on long term disease activity monitoring is under strain. It is important to understand the nature of illnesses and treatment of long term follow-up patients to decide management strategies.

Objectives

The aim of this quality improvement project was to understand profile of disease and management of patient being seen as long term follow-up (defined as >2 years follow-up after their first presentation in specialist clinic).

Methods

This was a single point, retrospective cohort analysis of patients seen in rheumatology clinics in a district general hospital, UK in March 2021. We reviewed consecutive 120 follow-up patients and recruited 80 patients who had >2yrs follow-up. We have a community rheumatology service arm where all patients with stable inflammatory arthritis on non-biologic treatments are reviewed while patients with multisystem complicated illness and biologics are seen in secondary care. The stable patients from community clinics have not been included in this analysis. The data was reviewed using clinic letters, date of first appointment & last appointment. We looked at gender, age, diagnosis, number of follow ups in the first and last year, disease activity scores of the respective diagnosis and treatment given.

Results

Sixty six percent of follow-up patients are long term with complicated illness or treatment. Of these 52 patients (65%) were female with median age 64 years (range 23-94 years). Median duration of follow up for this group of patients was 6 years (range 2-11 years). Inflammatory arthritis was the most common diagnosis in 75% of patients (11 patients were Psoriatic arthritis, 30- Rheumatoid arthritis, 7- undifferentiated inflammatory arthritis and 7- Axial spondyloarthritis), 17.5% connective tissue disease, 11.2% vasculitis and others (Still’s disease) 3.7%. Some patients had more than one diagnoses. The number of follow ups in the first year ranged from 1-13 (median 4). In final year of analysis, patients were seen median of 3 times (range1-8). Amongst them, 25% of patients were seen 4 or more times. The commonly prescribed drugs were methotrexate (41.2%), sulfasalazine(17.5%), hydroxychloroquine(15%), leflunomide (7.5%),biologics (8.7%), mycophenolate mofetil and azathioprine (6.5%).The activity scores such as DAS28, BVAS, PsARC and BASDAI were documented in 46 patients (57.5%).

Conclusion

This study shows that 66.6% of follow-up patients in rheumatology clinics are complicated long term conditions on immunomodulatory treatment. Despite T2T approach, use of combination DMARDs and early use of biologics, majority are inflammatory arthritis. It also shows that even after median follow-up of 6 years, these patients require an average review 3 or more times per year. The reasons for this may be poor disease control, disease complications, comorbidities and medication side effects. Further analysis is ongoing to look into these aspects for better disease control and long term outcome.

Disclosure of Interests

None declared

AB1556-HPR IDENTIFYING BARRIERS IN EARLY RECOGNITION AND MANAGEMENT OF PATIENTS WITH AXIAL SPONDYLOARTHRITIS: A RETROSPECTIVE REVIEW

Background

Axial spondyloarthritis are immune and genetically mediated inflammatory arthritis where there is significant delay in diagnosis and management of roughly 8.5 years; leading to poorer outcome and quality of life for a patient.

Objectives

This aim of audit was to improve the identification and referral pathways for patients with axial spondyloarthritis in South West Essex United Kingdom as per agreed NICE & EULAR criteria.

Methods

This was a retrospective audit of 35 patients diagnosed as Axial Spondyloarthritis in secondary care and those which was referred to secondary care by community triage MSK service (Connect) as Axial Spondyloarthritis, between January 2019 and March 2020. Data was extracted to look at demographics, diagnostic investigations performed, duration from symptom onset to diagnosis and the patient journey to secondary care.

Results

Out of total 35 patients, 63% were males with a median age of 35 years. Of all the GP referrals 17% were directly to secondary care and 71% were via triage service. Twelve percent of referrals came from other specialties.

The average timeframe from symptoms onset to referral by GP was 7.7 years. Average time before a patient was seen by a rheumatologist after referral was 4.4 months.

After evaluation in clinic, 30 cases (85.7%) were finally diagnosed as AxSpA after rheumatologist’s review. Rest were mechanical back pain. Inflammatory back pain was mentioned in 18% of referrals by GP and 80% of referrals letters by triage service. Base line investigations included: CRP was in 39% of cases under GP care and 100% cases under triage service. Additionally, HLAB27, X ray and MRI tests were done in 22%, 17% and 22% of GP cases respectively and 86%, 80% and 80% of cases from triage service. After specialist review, HLAB27 was positive in 49% of patients, X ray positive sacroileitis in 54.5% patients and rest had MRI positive sacroileitis and spinal features. Some had both X ray and MRI investigations.

Conclusion

Lack of education and awareness about spondyloarthropathy remains the most prominent factor behind delay to diagnosis. Lack of important information and clinical features on referral letters are also a contributing factor. It is evident that early referral to rheumatologist care and early triaging during reviews are crucial to diagnose AxSpA. We are piloting use of SPADE tool in suspected AxSpA cases to guide clinical reasoning and early referrral.

Disclosure of Interests

None declared

AB0165 MALIGNANCY AS PREDOMINANT CAUSE OF DEATH IN RHEUMATOID ARTHRITIS: REVIEW OF DATA FROM ‘BASILDON EARLY ARTHRITIS COHORT’

Background

Rheumatoid arthritis is a chronic inflammatory autoimmune condition historically linked to increased mortality with predominant contribution from cardiovascular, respiratory, infectious and neoplastic causes. There is evidence of decreasing cardiovascular mortality through improvements in preventative and treatment strategies. Recent literature has also suggested overall improvement in RA-associated mortality attributed to contemporary advances in disease control. There is a need to assess if such outcomes are reflected in the real world setting and to identify elements that continue to promote poorer outcomes.

Objectives

To assess long-term outcome in patients diagnosed with rheumatoid arthritis from the ‘Early Arthritis Cohort’ at a district general hospital in UK.

Methods

A retrospective cohort study was conducted on 185 patients newly diagnosed with rheumatoid arthritis between 2009 & 2013. Patients fulfilling the ACR/EULAR 2010 criteria were included. Anonymised data from the Basildon Early Arthritis registry was analysed. Measured parameters included patient demographics, disease activity score (DAS28), treatment regime, development of co-morbidity & mortality.

Results

Complete data was available for analysis in 171 patients. This comprised 60 men & 111 women with median age of 57 years (IQR 47 - 67 years) and median follow-up time of 90 months (IQR 63 - 108 months). Thirty nine percent were current or ex-smokers. At baseline, 40% of patients had DAS28 score > 5.1, this reduced to 2.5% at time of their last follow up. 74% of patients were in clinical remission at last follow up with 11.7% achieving drug-free remission, 40.4% remaining on single csDMARD, 29.8% on combination csDMARD & 18.1% on biologic therapy.

Analysis of new comorbidities revealed cancer burden of 12.9% (22/171) with lung cancer having highest incidence (n= 9). Other comorbidities recorded were cardiovascular 11.1% (19/171), pulmonary 5.8% (10/171) and cerebrovascular disease 5.3% (9/171).

A crude mortality rate of 19.3% (33/171) was observed in our cohort over a median period of 7.5 years follow-up. The incidence mortality rate was 174/10,000 person-years of follow-up and standardised mortality ratio was 2.09 (95% CI 1.44 – 2.86). Majority of patients died five or more years after initial diagnosis (67%) with most deaths occurring in the 6th year after disease onset. Patients in the mortality group had higher disease activity scores at their last follow-up compared to the remaining cohort (p=0.017).

More deaths were recorded from underlying malignancy 7.6% (n= 13) than with cardiovascular disease 4.7% (n= 8). Eight out of 13 cases were identified as lung cancer deaths. Breast, bladder, pancreatic and ovarian cancer constituted remaining cases. Other causes of death were from chronic obstructive pulmonary disease (n= 3), dementia/frailty (n = 3), interstitial lung disease (n= 2), infection (n= 2), stroke (n = 1) and chronic liver disease (n= 1).

Conclusion

Despite achieving remission in majority of patients, long-term analysis reveals that mortality in this cohort is significantly elevated compared to the general population. To best of our knowledge this is the first real-world study showing malignancy as the predominant cause of morbidity and mortality in rheumatoid arthritis.

References

[1]Abhishek A, Nakafero G, Kuo CF, Mallen C, Zhang W, Grainge MJ & Doherty M. (2018). Rheumatoid arthritis and excess mortality: down but not out. A primary care cohort study using data from Clinical Practice Research Datalink. Rheumatology (Oxford, England), 57(6), 977–981.

[2]Zhang Y, Lu N, Peloquin C, Dubreuil M, Neogi T, Aviña-Zubieta JA, Rai SK & Choi HK. (2017). Improved survival in rheumatoid arthritis: a general population-based cohort study. Annals of the rheumatic diseases, 76(2), 408–413.

[3]Mensah GA, Wei GS, Sorlie PD, Fine LJ, Rosenberg Y, Kaufmann PG, Mussolino ME, Hsu LL, Addou E, Engelgau MM & Gordon D. (2017). Decline in Cardiovascular Mortality: Possible Causes and Implications. Circulation research, 120(2), 366–380.

Disclosure of Interests

None declared

AB0262 CLINICAL EFFICACY OF SWITCHING FROM ORAL TO SUBCUTANEOUS METHOTREXATE IN MANAGEMENT OF RHEUMATOID ARTHRITIS: EXPERIENCE FROM OUT-PATIENT SETTING OF A DISTRICT GENERAL HOSPITAL IN UK

Background:

Methotrexate (MTX) is an anchor drug in the treatment of Rheumatoid arthritis. The literature review has shown that subcutaneous (SC) methotrexate has shown better efficacy, less adverse side effects and better compliance in inflammatory arthritis. Our department modified Inflammatory arthritis pathway in 2018 where all patient with moderate or severe disease are switched from oral to SC Methotrexate injection for improved management.

Objectives:

The aim of our study is to review whether switching of oral methotrexate (PO MTX) to subcutaneous methotrexate (SC MTX) helps to improve disease activity in patients with rheumatoid arthritis and avoids the need to introduce biologic therapy.

Methods:

We conducted a retrospective audit of patients with rheumatoid arthritis seen between January 2018 to January 2020 recording their age, gender, diagnosis, date of MTX switch and disease activity score 6 months after switching to SC MTX. Significance of change was calculated with test of proportion/chi square test.

Results:

Fifty patients were reviewed, thirty eight (76%) were female and twelve (24%) were male with age ranging between 34 - 86 years (median 61.5 years). Switching to MTX injection was done within 2 yrs of diagnosis in 21 (42%) patients, between 2-5 yrs of diagnosis in 11 (22%) patients and more than 5 yrs after diagnosis in 18 (36%) patients. The main reasons of switching were either maximum MTX dose (25mg) or intolerance to oral MTX at any dose.

After switching methotrexate, review at 6 months showed 26 patients (52%) in remission (compared to 6 at baseline) and 3 (6%) patients avoided the need to go on biologic therapy. Five patient commenced on biologic therapy between 3 and 6 months.

Table 1.

Disease activity compared at Baseline and at 6 months

Disease ActivityBaselineAt 6 monthsRemission <2.6626 (p<0.0001)Mild (26-3.19)1110Mod (3.2 - 5.09)259 (p<0.01)Severe (>5.1)85

Conclusion:

Switching to SC Methotrexate even in patients with long duration of disease results in significant number of patients achieving remission or lower disease activity (P<0.001). This may obviate the need of biologics therapy

Disclosure of Interests:

None declared

Comparison of Fiberoptic-Guided Tracheal Intubation Through Intubating Laryngeal Mask Airway (ILMA) FastrachTM and Ambu® Aura-i™: A Randomized Clinical Study

Background and aim

The primary aim of the study was to compare the intubation characteristics and effectiveness of intubating laryngeal mask airway (ILMA) and Ambu® Aura-i™ as a conduit for facilitating fiberoptic-guided intubation.

Methods

Eighty patients were enrolled in the randomized-controlled hospital-based study. After inducing general anesthesia, an appropriately sized ILMA (group 1)/Ambu Aura-I (group 2) was placed. Fiberoptic assessment of the glottic view was done followed by fiberoptic-guided tracheal intubation. The time taken for the insertion of ILMA/Ambu Aura-i, glottic view grading, time taken for fiberoptic-guided intubation, ease of intubation, time taken for the removal of ILMA/Ambu Aura-i were recorded. Data analysis was done using the two-tailed independent t-test, paired t-test, and Fisher’s exact probability test.

Result

Anthropometric and airway parameters were similar in both groups. The success rate of the insertion of both devices was 100%. In group 1, the mean time taken for the insertion was 20.53±1.91, and it was 13.98±2.4 in group 2 (P<0.001S). Fiberoptic assessment of the glottic view in group 1 (ILMA group) was grade 1 in 80% of the patients, whereas it was 92% in group 2 (Ambu Aura-i) (P=0.54). The mean time taken for fiberoptic-guided intubation was 14.95±1.85 in group 1 and 14.15±1.37 in group 2 (P>0.001). No significant difference was observed according to the number of attempts in intubating through ILMA/Ambu Aura-i. Seventy-five percent (75%) in group 1 and 87.5% in group 2 were successfully inserted on the first attempt (𝑝 = 0.33). The time taken for the removal of the device was 11.87 +1.265 seconds in group 1 and 11.25±1.58 seconds in group 2 (P=0.054).

Conclusion

The Ambu Aura-i scores superiorly over ILMA in requiring less time for successful insertion on the basis of statistical analysis and hence appears to be a better independent ventilatory device.

AB0529 TEMPORAL ARTERY ULTRASOUND (TAUS) IS A RELIABLE TECHNIQUE TO RULE OUT GCA EVEN IN THE LEARNING PHASE

Background:

Giant cell arteritis (GCA) is an emergency. The initial treatment with high dose glucocorticoids (GC) is often started on clinical suspicion without waiting for Temporal artery biopsy (TAB) results, which can take days to be available. TAUS is a simple, non-invasive test which is readily available. However, like any other ultrasound, it is also operator dependent. A positive halo sign is the most specific abnormality seen on TAUS in GCA patients. The percentage of false positive TAUS in GCA diagnosis is low (1), but it can result in over diagnosis and unnecessary exposure to high dose GC in elderly population.

Objectives:

We looked at the reliability of TAUS in ruling out GCA after it was introduced within our rheumatology department one year ago.

Methods:

We adopted the quality improvement methodology for assessment. Retrospective data of suspected GCA patients was collected over the last two years. TAUS was introduced regularly to the investigative plan after eleven months. Two Rheumatology consultants were trained in TAUS. Results were compared before and after the introduction of ultrasound as a diagnostic tool. In collecting the data, our main focus for documentation was based on clinical symptoms, TAUS and TAB results. We aimed to increase the awareness of appropriate GCA referrals among the primary and secondary care with the support of teaching sessions.

Results:

From January 2018 to November 2019, 101 patients were referred to rheumatology with suspected GCA. Median age of our cohort was 72 years with male to female ratio of 1:3. 35 patients were referred in the first 11 months out of which, 10 (28.6%) were diagnosed with GCA. TAUS and TAB was done in 20% and 49% of patients respectively. 66 patients were referred in the next 12 months after TAUS was introduced. Out of 66, 14 patients (21.2%) were diagnosed as GCA. TAUS and TAB were done in 82% and 38% of the patients respectively. As listed in table 1, only 1 patient was found to have positive TAB after a negative TAUS (false negative). All of patients with positive TAUS were treated as GCA on the basis of clinical grounds, irrespective of TAB results. Despite the regular use of TAUS as a diagnostic tool in the second phase, there is a higher percentage of patients (78.8%) in which GCA was ruled out.

TAUS introductionBefore regular TAUS(Jan 2018 – Nov 2018)After regular TAUS(Dec 2018 – Nov 2019)Patients referred3566GCA10 (28.6%)14 (21.2%)Not GCA25 (71.4%)52 (78.8%)TAUS done in20%82%TAB done in49%38%TAUS -ve and TAB +ve01TAUS +ve and TAB -ve/not done28

Conclusion:

After the routine introduction of TAUS, the percentage of patients diagnosed with GCA has declined and clinicians have been able to exclude suspected GCA diagnosis in a larger proportion of patients referred. This is noteworthy as our Rheumatologists are still in the learning phases of determining the significance of utility of TAUS. There is only a small decline in TAB frequency, which is expected to go down further in the coming years. We also noticed that the number of patients referred has almost doubled. This might be due to better education and awareness at the primary and secondary care level which was done as part of the project.

References:

[1]Fernández E, Monjo I, Bonilla G, et alOP0210 FALSE POSITIVES OF ULTRASOUND IN GIANT CELL ARTERITIS. SOME DISEASES CAN ALSO HAVE HALO SIGNAnnals of the Rheumatic Diseases2019;78:181

Disclosure of Interests:

None declared

Clinical evaluation of Ambu® Aura-i™ - A new intubating laryngeal mask airway as an independent ventilatory device and a conduit for tracheal intubation in pediatric patients

Background:

Ambu® Aura-i™, a recently introduced second generation supraglottic airway device has been designed to function as an independent ventilatory device as well as a conduit for passage of conventional cuffed tracheal tubes through it. There is dearth of literature on experience of tracheal intubation through intubating laryngeal mask airway (ILMA) in paediatric age group. This study was conducted to study the ventilatory effectiveness and the intubating characteristics of Ambu® Aura-i™ in paediatric patients.

Aim:

To study the effectiveness of Ambu ® Aura-i ™ as a supraglottic device for its ventilatory effectiveness and intubation characteristics in paediatric patients.

Objectives:

To study the Ventilatory effectiveness of Ambu ® Aura-i ™ in terms of: 1) Time taken in insertion of Ambu ® Aura-i ™. 2) No of attempts made for successful insertion of Ambu ® Aura-i™. 3) Tidal volume attained on positive pressure ventilation. 4) Etco2, Spo2 and Leak pressure achieved. To study the Intubating characterstics of Ambu ® Aura-i ™ in terms of :- 1) Grade of alignment of the ventilating orifice achieved in relation to the larynx in the fibre optic view. 2) Time taken in intubation through Ambu ® Aura-i ™. 3) Number of attempts made in intubation. 4) Time taken for removal of the Ambu ® Aura-i ™ after intubation through it has been accomplished.

Method:

Sixty three children undergoing elective surgery under general anaesthesia requiring intubation of trachea, weighing between 5-30 kg were stratified into 3 groups (n= 21) each. Ambu® Aura-i™ size 1.5 , 2.0 ,2.5 were used based on their body weight for airway management. Ventilatory effectiveness was studied in terms of success rate, number of attempts made at insertion, time taken in insertion, tidal volume delivered and leak pressure achieved. Intubating characterstics studied during fibreoptic guided tracheal intubation included grade of alignment of the ventilating orifice achieved in relation to the larynx in fibre optic view, time taken in fibreoptic guided tracheal intubation, success rate and number of attempts made at intubation. Time taken in removal of the device and complications observed were also recorded.

Results:

Ambu® Aura-i™ insertion, fibreoptic guided tracheal intubation and device removal were successful in all the patients in first attempt. The mean time taken in successful device insertion was 10.83±2.04 sec. The mean tidal volume delivered was 7.88±1.33 ml/kg body weight and mean leak pressure achieved was 16.27±5.2 cm H2O. The fibreoptic guided intubation was possible in first attempt in 100% of the patients (n=63). The Fibre optic view was grade 1 in 82.55% patients (n=52 /63) and grade 2 in 17.46% (n=11/ 63) patients. The mean time taken in fibre optic guided intubation was 12.68 ±2.82 sec. The mean time taken in removal of the device over the tracheal tube was 12.27 sec. There was no significant incidence of trauma to soft tissues, sore throat, laryngospasm or hoarseness of voice.

Conclusion:

On the basis of observations of this study, we conclude that Ambu ® Aura-i ™ is not only an effective ventilatoy device, but also an excellent conduit for fibre optic guided intubation using conventional uncuffed endotracheal tube in paediatric patients. Ambu ® Aura-i ™ , is also valuable for establishing rapid airway access in emergent difficult paediatric airway.

P681Acute Myocardial Infarction in patients with Leukaemia: A national analysis of prevalence, predictors and outcomes in United States hospitalisations (2004 to 2014)

Background

Patients with leukaemia are at increased risk of cardiovascular events. There is limited outcomes data for patients with a history of leukaemia who present with an acute myocardial infarction (AMI).

Purpose

To examine the prevalence and clinical characteristics of patients with leukaemia presenting with AMI, and evaluate differences in clinical outcomes according to the subtype of leukaemia in comparison to patients without leukaemia.

Methods

We analysed the Nationwide Inpatient Sample (2004–2014) for patients with a primary discharge diagnosis of AMI and concomitant leukaemia, and further stratified according to the subtype of leukaemia into 4 groups; AML; ALL; CML; and CLL. Multiple logistic regression was conducted to identify the association between leukaemia and major acute cardiovascular and cerebrovascular events (MACCE; composite of mortality, stroke and cardiac complications) and bleeding.

Results

Out of 6,750,927 AMI admissions, a total of 21,694 patients had a leukaemia diagnosis. The leukaemia group experienced higher rates of MACCE (11.8% vs. 7.8%), mortality (10.3% vs. 5.8%) and bleeding (5.6% vs. 5.3%). Following adjustments, leukaemia was independently associated with increased odds of MACCE (OR 1.26 [1.20,1.31]) and mortality (OR 1.43 [1.37,1.50]) without an increased risk of bleeding (OR 0.86 [0.81,0.92]). Acute myeloid leukaemia (AML) was associated with approximately three-fold risk of MACCE (RR 2.81 [2.51, 3.13]) and a four-fold risk of mortality (RR 3.75 [3.34, 4.22]) (Figure 1). Patients with leukaemia were less likely to undergo coronary angiography (CA) (48.5% vs. 64.5%) and percutaneous coronary intervention (PCI) (28.2% vs. 42.9%) compared to those without leukaemia.

Figure 1.Relative risk of adverse events

Conclusion

Patients with leukaemia, especially those with AML, are associated with poor clinical outcomes after AMI, and are less likely to receive CA and PCI compared to those without leukaemia. A multi-disciplinary approach between cardiologists and haematology oncologists may improve the outcomes of patients with leukaemia after AMI.

PNEUMATIC RETINOPEXY IN RHEGMATOGENOUS RETINAL DETACHMENT

Existing surgical modes for retinal detachment are elaborate and extremely complex. We have treated 20 cases of rhegmatogenous retinal detachment with pneumatic retinopexy which is Iess time consuming and does not require hospitalization. After pneumatic retinopexy reattachment of retina was achieved in 15 (75%) eyes. In 2 eyes retinal reattachment was achieved after repeating intravitreal injection of sulphur hexafluoride gas. Remaining 3 eyes were secondarily treated with scleral buckle surgery. One case needed vitreoretinal surgery. In pneumatic retinopexy there is minimum tissue handling and functional results are good.

Perioperative neonatal and paediatric blood transfusion

Paediatric patients undergoing surgical procedures commonly require some volume of blood or blood component replacement in the perioperative period. Paediatric patients undergoing major surgery associated with substantial blood loss should be evaluated pre-operatively. Pre-operative correction of anaemia may be done considering the age, plasma volume status, clinical status and comorbidities. Maximum allowable blood loss (MABL) for surgery must be calculated, and appropriate quantity of blood and blood components should be arranged. Intraoperative monitoring of blood loss should be done, and volume of transfusion should be calculated in a protocol based manner considering the volemia and the trigger threshold for transfusion for the patient and the MABL. Early haemostasis should be achieved by judicious administration of red blood cells, blood components and pharmacological agents.

Intubating laryngeal mask airway as an independent ventilatory and intubation device. A comparison between supine, right lateral and left lateral

Background

Sudden loss of airway in patients in the lateral position has always been proven to be difficult to manage with conventional laryngoscopy. We performed a randomized controlled trial to prove the success rate of ventilation and intubation in the lateral position via intubating laryngeal mask airway (ILMA).

Methods

Ninety patients were divided into three groups of 30 patients each, positioned supine, right lateral, and left lateral randomly. Each group comprised of both sexes of American Society of Anesthesiologists grade I and II, aged between 18-55 years with normal airway posted for surgery under general anesthesia. Patients were pre-medicated with fentanyl followed by induction with propofol and neuromuscular blockade with rocuronium. ILMA was inserted and blind tracheal intubation via ILMA was done. The success rate, time taken and the number of adjusting maneuvers used for both procedures were recorded. The data was tabulated and analyzed using ANOVA (analysis of variance), multiple 't' test and chi square.

Results

The success rate of intubation (96%) and time taken in insertion and intubation was found to be quite similar in all the three groups.

Conclusions

We conclude that the ILMA has an important role to play in the emergency management of airways in patients in the lateral position in terms of ease, success rate and time taken.

Effect of short-term propofol administration on pancreatic enzymes and lipid biochemistry in children between 1 month and 36 months

BACKGROUND

Use of propofol in pediatric age group has been marred by reports of its adverse effects like hypertriglyceridemia and acute pancreatitis, although a causal relation has not yet been established.

OBJECTIVES

This prospective, clinical trial was carried out to evaluate the effects of short-term propofol administration on serum lipid profile and serum pancreatic enzymes in children of ASA physical status I and II aged between 1 month and 36 months.

METHODS

Anesthesia was induced with Propofol (1%) in the dose of 3 mg·kg(-1) intravenously and was maintained by propofol infusion (0.5%) at the rate of 12 mg·kg(-1·) h(-1) for the first 20 min and at 8 mg·kg(-1·) h(-1) thereafter. The mean dose of propofol administered was 12.02 ± 2.75 mg·kg(-1) (fat load of 120.2 ± 27.5 mg·kg(-1) ). Lipid profile, serum amylase, and lipase were measured before induction of anesthesia, at 90 min, 4 h, and finally 24 h after induction.

RESULTS

Serum lipase levels (P < 0.05), serum triglyceride levels (P < 0.05), and serum very low-density lipoproteins VLDL levels (P < 0.05) were raised significantly after propofol administration from baseline although remained within normal limits. Serum cholesterol levels and serum low-density lipoproteins LDL levels showed a statistically significant fall over 24 h. No significant changes in serum pancreatic amylase levels were seen (P > 0.05). None of the patients developed any clinical features of pancreatitis in the postoperative period.

CONCLUSION

We conclude that despite a small, transient increase in serum triglycerides and pancreatic enzymes, short-term propofol administration in recommended dosages in children of ASA status I and II aged between 1 month and 36 months does not produce any clinically significant effect on serum lipids and pancreatic enzymes.

Comparison of periosteal pedicle graft and subepithelial connective tissue graft for the treatment of gingival recession defects

BACKGROUND

The use of periosteum as a pedicle graft in the treatment of gingival recession defects is a recent advancement. The subepithelial connective tissue graft (SCTG) is considered the gold standard for the treatment of gingival recession defects. The present randomized controlled trial was done to compare periosteal pedicle graft (PPG) with SCTG for the treatment of gingival recession defects.

METHODS

10 males and 10 females between the ages of 16 and 40 years (mean age 25.2 years) with Miller's Class I and II recessions ≥3 mm participated in this one-year clinical study. They were assigned randomly to test group (PPG) and control group (SCTG). Results were evaluated based on parameters measuring patient satisfaction and clinical outcomes associated with two treatment procedures. Significance was set at p < 0.05.

RESULTS

At the end of the study, the defect coverage was 3.1 ± 0.13 mm or 92.6% in the test group compared to the control group in which the defect coverage was 2.70 ± 0.11 mm or 88.5%. The difference between the two groups was statistically significant (p < 0.0001). The average residual defect was comparable between the two groups, i.e. 0.3 ± 0.67 and 0.5 ± 0.84 in the PPG and SCTG group respectively. The test group was rated higher in terms of overall patient satisfaction (p < 0.02) and comfort during and after the procedure (p < 0.001).

CONCLUSIONS

PPG and SCTG have comparable clinical effectiveness, but PPG is superior to SCTG in terms of patient-centred outcomes, reflecting improved patient comfort and overall patient satisfaction.

Is intimal hyperplasia a marker of neuro-ophthalmic complications of giant cell arteritis?

OBJECTIVE

The ischaemic complications of giant cell arteritis (GCA) such as blindness and stroke may result from luminal narrowing of the affected arteries. This study focuses on the association between the severity of intimal proliferation on temporal artery biopsy (TAB) histology and neuro-ophthalmic complications (NOCs) of GCA.

METHOD

We identified 30 cases of biopsy-proven temporal arteritis. One histopathologist (blinded to the clinical details) evaluated the TAB specimens and categorized the degree of maximum stenosis due to intimal hyperplasia into four grades: grade 1 is <50% luminal occlusion due to intimal hyperplasia, grade 2 is 50-75%, grade 3 is >75% and grade 4 is complete luminal occlusion. A second histopathologist (also blinded to the clinical details) independently evaluated the TAB specimens using the same grading system. The NOCs in these patients were noted after a case record review.

RESULTS

Of the 30 patients, 12 had NOC-10 with eye complications (complete visual loss, anterior ischaemic neuropathy, visual field defects), one patient had cerebral infarcts and one had both cerebral infarcts and vision loss. There was evidence for a statistically significant trend of NOC associated with higher intimal hyperplasia scores (P = 0.001). The scores of the histopathologists agreed for 23 (77%) patients and differed by 1 category for the remaining 7 (kappa-statistic 0.88).

CONCLUSIONS

Our study suggests that the degree of intimal hyperplasia on TAB histology (routinely available to all hospital units) seems to be closely associated with NOCs of GCA. The study highlights the possible prognostic as well as diagnostic role of the biopsy. We feel that intimal hyperplasia noted in biopsy specimens may help us in the risk stratification of GCA patients and targeting of appropriate and novel therapies.

Polyradiculopathy in a patient of systemic lupus erythematosus

The relationship of the neurological manifestations to the lupus disease process is not always clear. We present a case of systemic lupus erythematosus (SLE) with subacute onset muscle weakness, which was due to polyradiculopathy, a rarely described neurological manifestation of SLE.

Evidence for the presence of HABP1 pseudogene in multiple locations of mammalian genome

The gene encoding hyaluronan-binding protein 1 (HABP1) is expressed ubiquitously in different rat tissues, and is present in eukaryotic species from yeast to humans. Fluorescence in situ hybridization indicates that this is localized in human chromosome 17p13.3. Here, we report the presence of homologous sequences of HABP1 cDNA, termed processed HABP1 pseudogene in humans. This is concluded from an additional PCR product of ~0.5 kb, along with the expected band at approximately 5 kb as observed by PCR amplification of human genomic DNA with HABP1-specific primers. Partial sequencing of the 5-kb PCR product and comparison of the HABP1 cDNA with the sequence obtained from Genbank accession number AC004148 indicated that the HABP1 gene is comprised of six exons and five introns. The 0.5-kb additional PCR product was confirmed to be homologous to HABP1 cDNA by southern hybridization, sequencing, and by a sequence homology search. Search analysis with HABP1 cDNA sequence further revealed the presence of similar sequence in chromosomes 21 and 11, which could generate ~0.5 kb with the primers used. In this report, we describe the presence of several copies of the pseudogene of HABP1 spread over different chromosomes that vary in length and similarity to the HABP1 cDNA sequence. These are 1013 bp in chromosome 21 with 85.4% similarity, 1071 bp in chromosome 11 with 87.2% similarity, 818 bp in chromosome 15 with 82.3% similarity, and 323 bp in chromosome 4 with 84% similarity to HABP1 cDNA. We have also identified similar HABP1 pseudogenes in the rat and mouse genome. The human pseudogene sequence of HABP1 possesses a 10 base pair direct repeat of "AGAAAAATAA" in chromosome 21, a 12-bp direct repeat of "AG/CAAATTA/CAA/TTA" in chromosome 4, a 8-bp direct repeat of "ACAAAG/TCT" in chromosome 15. In the case of chromosome 11, there is an inverted repeat of "AGCCTGGGCGACAGAGCGAGA" ~50 bp upstream of the HABP1 pseudogene sequence. All of the HABP1 pseudogene sequences lack 5' promoter sequence and possess multiple mutations leading to the insertion of premature stop codons in all three reading frames. Rat and mouse homologs of the HABP1 pseudogene also contain multiple mutations, leading to the insertion of premature stop codons confirming the identity of a processed pseudogene.

HIV in Nepal: is it rare or the tip of an iceberg?

Acquired immunodeficiency syndrome (AIDS) has reached alarming proportions in SE Asia. The magnitude of the epidemic is projected to exceed that of sub-Saharan Africa as we enter the 21st century. Nepal has much in common with India geopolitically and socially and the prevalence of HIV is expected to be no different from the rest of SE Asia. However, evidence thus far paints a different picture altogether--a very low prevalence of HlV even in high-risk population groups. This is surprising, particularly since high-risk behaviour is evidenced by a high rate of drug abuse. In addition, other communicable diseases commonly associated with HIV infection, such as tuberculosis and HBV/HCV infection, are common in Nepal and yet still the prevalence of HIV infection in these patients and in the general population is reported to be low. This paper identifies some of these anomalies and attempts to analyse the reasons for this discrepancy. We emphasize the need for extended survey and strict surveillance to avoid an explosion of this dreaded infection.

Biochemical, biophysical, and functional characterization of bacterially expressed and refolded receptor binding domain of Plasmodium vivax duffy-binding protein

Invasion of erythrocytes by malaria parasites is mediated by specific molecular interactions. Plasmodium vivax is completely dependent on interaction with the Duffy blood group antigen to invade human erythrocytes. The P. vivax Duffy-binding protein, which binds the Duffy antigen during invasion, belongs to a family of erythrocyte-binding proteins that also includes Plasmodium falciparum sialic acid binding protein and Plasmodium knowlesi Duffy binding protein. The receptor binding domains of these proteins lie in a conserved, N-terminal, cysteine-rich region, region II, found in each of these proteins. Here, we have expressed P. vivax region II (PvRII), the P. vivax Duffy binding domain, in Escherichia coli. Recombinant PvRII is incorrectly folded and accumulates in inclusion bodies. We have developed methods to refold and purify recombinant PvRII in its functional conformation. Biochemical, biophysical, and functional characterization confirms that recombinant PvRII is pure, homogeneous, and functionally active in that it binds Duffy-positive human erythrocytes with specificity. Refolded PvRII is highly immunogenic and elicits high titer antibodies that can inhibit binding of P. vivax Duffy-binding protein to erythrocytes, providing support for its development as a vaccine candidate for P. vivax malaria. Development of methods to produce functionally active recombinant PvRII is an important step for structural studies as well as vaccine development.

Clinical relevance of IgA rheumatoid factor (RF) in children with juvenile rheumatoid arthritis

This study proposed to investigate the prevalence and clinical relevance of serum immunoglobulin A (IgA) rheumatoid factor (RF) in juvenile rheumatoid arthritis (JRA) as published reports vary in their conclusion. Sera of 82 children with JRA and 25-age and sex-matched healthy children were measured for IgA RF by an enzyme linked immunoassay using human IgG as the antigen. Forty-three percent of the disease population were positive and the prevalence in pauciarticular, polyarticular and systemic onset was 9/18 (50%), 21/47 (44.7%) and 5/17 (27.7%) respectively when mean + 2SD of normal was taken as the cut-off value. By defining the upper limit of normal as mean + 6SD, 16/47 (34%) were positive in the polyarticular as compared to 2/18 (11.1%) in pauciarticular and 1/17 (5.8%) of systemic onset disease groups. The prevalence in the polyarticular subset with the upper cut-off limit was significantly higher than the pauciarticular and the systemic onset group (P < 0.05). Furthermore, the mean level of IgA RF was significantly higher in the polyarticular group compared to the mean level in the systemic onset group (P < 0.05). The mean level of IgA RF was also significantly higher (P < 0.05) in 61 children with active diseases.

Analysis of immune responses against T- and B-cell epitopes from Plasmodium falciparum liver-stage antigen 1 in rodent malaria models and malaria-exposed human subjects in India

Liver-stage antigen 1 (LSA-1) is a potential vaccine candidate against preerythrocytic stages of malaria. We report here the immunogenicity of linear synthetic constructs delineated as T(H)-cell determinants from the nonrepeat regions of Plasmodium falciparum LSA-1 in murine models and human subjects from areas where malaria is endemic in Rajasthan State, India. Seven peptide constructs (LS1.1 to LS1.7) corresponding to predicted T-cell sites from both the N- and C-terminal regions and peptide LS1R from a repeat region of PfLSA-1 were synthesized to analyze the cellular immune responses. These linear peptides were also tested for humoral responses in order to determine if there were any overlapping B-cell epitopes in the predicted T-cell sites. Most peptides induced cellular responses in peptide-immunized BALB/c and C57BL/6 mice as measured by proliferation and cytokine analysis. Cross-reactive T-cell recognition of P. falciparum-based peptides in Plasmodium berghei-immune animals was evaluated, but only one peptide, LS1.2 (amino acids 1742 to 1760) triggered T-cell proliferation and interleukin-2 and gamma interferon secretion in P. berghei-immune splenocytes of BALB/c and C57BL/6 mice as well as in Thamnomys gazellae (natural host of P. berghei ANKA). In an enzyme-linked immunosorbent assay with the peptides, only one peptide, LS1.1, was recognized by anti-P. berghei liver-stage serum. Three peptides (LS1. 1, LS1.2, and LS1.3) of the eight peptides tested in this study were recognized by a relatively large percentage of P. falciparum-exposed human subjects; the reactivities ranged from approximately 45% for LS1.3 to approximately 60% for LS1.1 and LS1.2. Interestingly, all of the eight putative T-cell determinants were also recognized by the sera collected from malaria patients, although the response was variable in nature. These T(H)- and B-cell epitopes may be of potential value for preerythrocytic antigen-based malaria subunit vaccine formulations.

Induction of protective immune responses by immunization with linear multiepitope peptides based on conserved sequences from Plasmodium falciparum antigens

A cysteine-containing peptide motif, EWSPCSVTCG, is found highly conserved in the circumsporozoite protein (CSP) and the thrombospondin-related anonymous protein (TRAP) of all the Plasmodium species analyzed so far and has been shown to be crucially involved in the sporozoite invasion of hepatocytes. We have recently shown that peptide sequences containing this motif, and also the antibodies raised against the motif, inhibit the merozoite invasion of erythrocytes. However, during natural infection, and upon immunization with recombinant CSP, this motif represents a cryptic epitope. Here we present the results of immunization studies with two linear multiepitopic constructs, a 60-residue (P60) and a 32-residue (P32) peptide, containing the conserved motif sequence. Both the peptides per se generated high levels of specific antibodies in BALB/c mice. P32 was found to be genetically restricted to H-2(d) and H-2(b) haplotypes of mice, whereas P60 was found to be immunogenic in five different strains of mice. The antibody response was predominantly targeted to the otherwise cryptic, conserved motif sequence in P60. Anti-P60 antibodies specifically stained the asexual blood stages of Plasmodium falciparum and Plasmodium yoelii in an immunofluorescence assay, recognized a 60- to 65-kDa parasite protein in an immunoblot assay, and blocked P. falciparum merozoite invasion of erythrocytes in a dose-dependent manner. Immunization with P60 also induced significant levels of the cytokines interleukin-2 (IL-2), IL-4, and gamma interferon in BALB/c mice. Moreover, >60% of mice immunized with P60 survived a heterologous challenge infection with a lethal strain of P. yoelii. These results indicate that appropriate medium-sized synthetic peptides might prove useful in generating specific immune responses to an otherwise cryptic but critical and putatively protective epitope in an antigen and could form part of a multicomponent malaria vaccine.

Labor ward workload waxes and wanes with the lunar cycle, myth or reality?

Objective: To test the validity of the statement "We are busy because it is getting close to the full moon" often heard on labor ward, by analysis of birth statistics in relation to lunar cycles.Method: Data for births from spontaneous onset labors for 12 lunar cycles from January 1 to December 31, 1994 was analyzed. Births resulting from induced labors were excluded. Birthrate for each day of the lunar cycle from new moon to full moon (ascending lunar phase) and from full moon to new moon (descending lunar phase) were analyzed using Pearson correlation coefficient. Birthrate at full moon was compared to that at new moon and that at mid ascending lunar phase was compared with that at mid descending lunar phase using t test.Results: There were 3706 spontaneous births during the study period. The average daily birthrate was 10.58 with standard deviation (SD) of 1.27. There was no statistically significant difference in the daily birthrate between the ascending and the descending lunar phases, r = -0.21. Statistical analysis showed no significant difference in the number of births at full moon as compared to that at new moon, P =.44. No difference was found on comparison of number of births during the mid ascending phase to that at the mid descending lunar phase, P =.84.Conclusion: Scientific analysis of data does not support the belief that the number of births increases as the full moon approaches, therefore it is a myth not reality.

Characterization of protective epitopes in a highly conserved Plasmodium falciparum antigenic protein containing repeats of acidic and basic residues

The delineation of putatively protective and immunogenic epitopes in vaccine candidate proteins constitutes a major research effort towards the development of an effective malaria vaccine. By virtue of its role in the formation of the immune clusters of merozoites, its location on the surface of merozoites, and its highly conserved nature both at the nucleotide sequence level and the amino acid sequence level, the antigen which contains repeats of acidic and basic residues (ABRA) of the human malaria parasite Plasmodium falciparum represents such an antigen. Based upon the predicted amino acid sequence of ABRA, we synthesized eight peptides, with six of these (AB-1 to AB-6) ranging from 12 to 18 residues covering the most hydrophilic regions of the protein, and two more peptides (AB-7 and AB-8) representing its repetitive sequences. We found that all eight constructs bound an appreciable amount of antibody in sera from a large proportion of P. falciparum malaria patients; two of these peptides (AB-1 and AB-3) also elicited a strong proliferation response in peripheral blood mononuclear cells from all 11 human subjects recovering from malaria. When used as carrier-free immunogens, six peptides induced a strong, boostable, immunoglobulin G-type antibody response in rabbits, indicating the presence of both B-cell determinants and T-helper-cell epitopes in these six constructs. These antibodies specifically cross-reacted with the parasite protein(s) in an immunoblot and in an immunofluorescence assay. In another immunoblot, rabbit antipeptide sera also recognized recombinant fragments of ABRA expressed in bacteria. More significantly, rabbit antibodies against two constructs (AB-1 and AB-5) inhibited the merozoite reinvasion of human erythrocytes in vitro up to approximately 90%. These results favor further studies so as to determine possible inclusion of these two constructs in a multicomponent subunit vaccine against asexual blood stages of P. falciparum.

Zones of atrial vulnerability. Relationships to basic cycle length

BACKGROUND

Bradycardia is commonly found in individuals at risk for paroxysmal atrial fibrillation (AF). However, a clear relationship between lengthening of basic cyclic length (BCL) and AF has not been demonstrated.

METHODS AND RESULTS

In 20 open-chest dogs, atrial refractoriness, AF vulnerability, and atrial activation times (ACTs) were determined in sinus rhythm and at BCLs of 400, 300, and 200 ms, and the findings at the same coupling intervals and stimulus strengths were compared. As BCL increased, AFV zone lengthened, and its outer limit occurred later in diastole. The outer limit of the AF vulnerability zone for a BCL was its relative refractory period; the inner limit, however, was not its effective refractory period. A border zone, defined by the inner limit of the AF vulnerability zone and the effective refractory period for a BCL, decreased as BCL lengthened, offsetting the increase in the AF vulnerability zone. The border zone was characterized by paradoxical stimulus current strength propagation relations and features suggesting supernormal conduction. ACT also increased with BCL lengthening. When AF induced by rapid atrial burst pacing was contrasted with AF induced by an extrastimulus, it tended to have a more disorganized pattern and lasted longer.

CONCLUSIONS

Lengthening of BCL increases the AF vulnerability zone, extending its outer limit later in diastole and comprising an increasing component of the total duration of the relative refractory period. Very short BCLs create conditions that also favor AF vulnerability.

Antibodies to a conserved-motif peptide sequence of the Plasmodium falciparum thrombospondin-related anonymous protein and circumsporozoite protein recognize a 78-kilodalton protein in the asexual blood stages of the parasite and inhibit merozoite invasion in vitro

Athrombospondin-related anonymous protein (TRAP) of the human malaria parasite Plasmodium falciparum shares highly conserved amino acid sequence motifs with the circumsporozoite protein of all plasmodia sequenced so far, as well as with unrelated proteins like thrombospondin and properdin. Although it was first described as an asexual blood stages protein, there has been some controversy about its expression in these stages. Pursuant to our interest in the conserved sequences within the malaria antigens, we synthesized an 18-residue peptide (18-mer) representing a conserved motif of TRAP and raised polyclonal antibodies against it. In an immunoblot assay in which we probed proteins from the asexual blood stages of the parasite, we found that this antibody recognized predominantly a 78-kDa protein in the whole parasite lysate. Furthermore, in another immunoblot, the recombinant TRAP constructs containing the conserved-motif sequence were distinctly recognized by the antipeptide antibodies, whereas a construct lacking the motif sequence was not, suggesting that the antibodies specifically cross-reacted with a protein which might be a TRAP-like protein present in the asexual blood stages of the parasite. Also, in an immunofluorescence assay, this antibody brightly stained the acetone-fixed trophozoites of the parasite. Most significantly, anti-18-mer immunoglobulin G, as well as antipeptide antibody against a smaller (nonamer) construct representing the most conserved motif within the 18-mer, inhibited the merozoite invasion of erythrocytes in a dose-dependent manner. These results provide evidence of the expression of TRAP or a TRAP-like protein in the asexual blood stages of the parasite and of a possible role of the conserved motifs in the parasite-host cell interaction during the process of invasion.

OUR EXPERIENCE OF IOL IMPLANTATION IN PAEDIATRIC AGE GROUP

Forty eyes of 35 patients in paediatric age group suffering from congenital/traumatic cataracts were operated. Posterior chamber intra ocular lens (PC IOL) implantation was carried out and followed for four years. Twenty one eyes (52.5%) showed visual recovery of 6/18 or better. Forward thrust was the commonest per operative complication. Uveitis and pupillary distortion were the common post operative complications. PC IOL implantation appears to be safe and promising procedure.

Conformationally constrained formyl methionyl tripeptides: structure-function study of analogs containing alpha,beta-dehydrophenylalanine and dehydroleucine

In order to probe the role of peptide backbone conformation on the biological activity of chemotactic peptides through conformationally constrained peptides, we synthesized the following three analogs of N-formyl-Met-Leu-Phe-OH (fMLF) containing dehydrophenylalanine (delta ZPhe) and dehydroleucine (delta ZLeu): formyl-Met-delta ZPhe-Phe-OCH3 (1), formyl-Met-delta ZLeu-Phe-OCH3 (2) and formyl-Met-delta ZPhe-delta ZPhe-OCH3 (3) and studied their conformational behavior in solution by 1H NMR and IR spectroscopy. The conformation of (1) was also examined by x-ray diffraction methods. Biological activity of these analogs was assessed for their ability to induce the release of beta-glucosaminidase from rabbit neutrophils. In addition, the chemotactic activity of analog (2) was also determined. We found that, in the solid state, (1) favors a type II beta-turn structure, stabilized by a 4-->1 intramolecular hydrogen bond. A similar structure was reported recently for (2) also. 1H NMR studies in solution suggest that the Phe NH is solvent shielded in both (1) and (2) and that a major population of peptide molecule exists in an intramolecular hydrogen bond stabilized type II beta-turn conformation. None of the NH groups in (3) and another analog, formyl-Met-Phe-Phe-OCH3 (4), appear solvent shielded, favoring an extended structure for these analogs. Analogs (2) and (4) are highly active indicating that both extended and beta-turn backbone conformations may be compatible with high activity and that the phenylalanine ring in the middle position is well accepted. Highly reduced activities of (1) and (3) suggest that delta ZPhe residue in position 2, irrespective of the preferred peptide backbone conformation, is not acceptable for high bioactivity. These results suggest that an induced fit mechanism may possibly be the most relevant one, but the nature and the topography of the side chains, particularly the middle residue, may be crucial for appropriate receptor ligand interactions.