Comparison of 2-Field and 5-Field Mydriatic Handheld Retinal Imaging in a Community-Based Diabetic Retinopathy Screening Program.

INTRODUCTION: The purpose of this study was to compare 2-field (2F) and 5-field (5F) mydriatic handheld retinal imaging for the assessment of diabetic retinopathy (DR) severity in a community-based DR screening program (DRSP). METHODS: This was a prospective, cross-sectional diagnostic study, evaluating images of 805 eyes from 407 consecutive patients with diabetes acquired from a community-based DRSP. Mydriatic standardized 5F imaging (macula, disc, superior, inferior, temporal) with handheld retinal camera was performed. 2F (disc, macula), and 5F images were independently assessed using the International DR classification at a centralized reading center. Simple (K) and weighted (Kw) kappa statistics were calculated for DR. Sensitivity and specificity for referable DR ([refDR] moderate nonproliferative DR [NPDR] or worse) and vision-threatening DR ([vtDR] severe NPDR or worse) for 2F compared to 5F imaging were calculated. RESULTS: Distribution of DR severity by 2F/5F images (%): no DR 66.0/61.7, mild NPDR 10.7/14.4, moderate NPDR 7.9/8.1, severe NPDR 3.3/5.6, proliferative DR 5.6/4.6, ungradable 6.5/5.6. Exact agreement of DR grading between 2F and 5F was 81.7%, within 1-step 97.1% (K = 0.64, Kw = 0.78). Sensitivity/specificity for 2F compared 5F was refDR 0.80/0.97, vtDR 0.73/0.98. The ungradable images rate with 2F was 16.1% higher than with 5F (6.5 vs. 5.6%, p < 0.001). CONCLUSIONS: Mydriatic 2F and 5F handheld imaging have substantial agreement in assessing severity of DR. However, the use of mydriatic 2F handheld imaging only meets the minimum standards for sensitivity and specificity for refDR but not for vtDR. When using handheld cameras, the addition of peripheral fields in 5F imaging further refines the referral approach by decreasing ungradable rate and increasing sensitivity for vtDR.

Development of Student Survey on Writing Nursing Care Plan: An exploratory sequential mixed-methods study.

AIM: To come up with a newly developed survey tool that will measure the students' level of quality in writing nursing care plans (NCPs). BACKGROUND: Exploring various challenges of students in writing NCP would enlighten educators to design innovative strategies on how to mitigate gaps between nursing education and practice. METHODS: This study utilized an exploratory sequential mixed-methods design in three stages. In phase 1, qualitative semi-structured interviews of 22 students were conducted, and the data were analysed using the Colaizzi method. In phase 2, qualitative results were transformed into survey components, constructs and items, and the data were developed into a new survey tool based on the nursing process system (NPS) model. In phase 3, a quantitative cross-sectional survey of 195 nursing students was conducted to measure their level of quality in writing NCP, and the data were analysed using descriptive statistics of the SPSS software. RESULTS: In the first (qualitative) phase, five themes emerged from various challenges of nursing students in writing care plans: (a) data gathering; (b) identifying clients' problems; (c) formulating sustainable goals; (d) providing appropriate interventions; and (5) recognizing client's outcomes. In the second phase, a valid and reliable tool called the Student Survey on Writing Nursing Care Plan (SSW-NCP) was developed and tested. Lastly, in the third (quantitative) phase, the nursing students have shown a 'very good' level of quality in writing NCP. CONCLUSION: Determining students' level of quality in writing NCP would come up with comprehensive ways of improving student competencies in patient care management. IMPLICATIONS FOR NURSING MANAGEMENT: The survey tool that is formulated from the study will provide relevant information for nurse educators and managers in managing students' and registered nurses' capabilities in writing an excellent care plan.

Accuracy of Integrated Artificial Intelligence Grading Using Handheld Retinal Imaging in a Community Diabetic Eye Screening Program.

Purpose: To evaluate mydriatic handheld retinal imaging performance assessed by point-of-care (POC) artificial intelligence (AI) as compared with retinal image graders at a centralized reading center (RC) in identifying diabetic retinopathy (DR) and diabetic macular edema (DME). Design: Prospective, comparative study. Subjects: Five thousand five hundred eighty-five eyes from 2793 adult patients with diabetes. Methods: Point-of-care AI assessment of disc and macular handheld retinal images was compared with RC evaluation of validated 5-field handheld retinal images (disc, macula, superior, inferior, and temporal) in identifying referable DR (refDR; defined as moderate nonproliferative DR [NPDR], or worse, or any level of DME) and vision-threatening DR (vtDR; defined as severe NPDR or worse, or any level of center-involving DME [ciDME]). Reading center evaluation of the 5-field images followed the international DR/DME classification. Sensitivity (SN) and specificity (SP) for ungradable images, refDR, and vtDR were calculated. Main Outcome Measures: Agreement for DR and DME; SN and SP for refDR, vtDR, and ungradable images. Results: Diabetic retinopathy severity by RC evaluation: no DR, 67.3%; mild NPDR, 9.7%; moderate NPDR, 8.6%; severe NPDR, 4.8%; proliferative DR, 3.8%; and ungradable, 5.8%. Diabetic macular edema severity by RC evaluation was as follows: no DME (80.4%), non-ciDME (7.7%), ciDME (4.4%), and ungradable (7.5%). Referable DR was present in 25.3% and vtDR was present in 17.5% of eyes. Images were ungradable for DR or DME in 7.5% by RC evaluation and 15.4% by AI. There was substantial agreement between AI and RC for refDR (κ = 0.66) and moderate agreement for vtDR (κ = 0.54). The SN/SP of AI grading compared with RC evaluation was 0.86/0.86 for refDR and 0.92/0.80 for vtDR. Conclusions: This study demonstrates that POC AI following a defined handheld retinal imaging protocol at the time of imaging has SN and SP for refDR that meets the current United States Food and Drug Administration thresholds of 85% and 82.5%, but not for vtDR. Integrating AI at the POC could substantially reduce centralized RC burden and speed information delivery to the patient, allowing more prompt eye care referral. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Cross-sectional Study on the Correlation of Stress and Sleep Quality of Learning Unit III (1st Year) to VII (5th Year) Medical Students from the University of the Philippines College of Medicine.

Background and Objective: Due to their academic load, medical students are highly susceptible to stress. Stress is one of the factors that can alter sleep quality which may consequently affect the cognitive performance of medical students. There has been a lack of published local literature that looks into the association between stress and sleep quality, especially during the COVID-19 pandemic. With this, the general objective of this study is to determine the effect of stress on the sleep quality of medical students from the University of the Philippines Manila - College of Medicine (UPCM). Methods: A cross-sectional study was conducted using a stratified random sample of 273 males and females of Learning Unit (LU) III (1st year) to VII (5th year) medical students from a college of medicine based in the Philippines, UPCM, during the second semester of the academic year 2021-2022. A self-administered questionnaire was distributed to assess sleep quality using the Pittsburgh Sleep Quality Index (PSQI), and stress level using the Kessler Psychological Distress Scale (K10). Kruskal-Wallis was used to test statistical differences between stress scores and the sleep quality of students from different year levels. Spearman's Rho was used to determine the correlation between stress and sleep, and a binary logistic regression was employed to study the association of stress with sleep while accounting for confounding variables namely caffeine intake, year level, daytime nap, duty hours, clinical rotation, sex, and age. Results: A high prevalence of stress (79.71%) and poor sleep quality (59.73%) among LU III to LU VII UPCM students were found, with a statistically positive correlation (ρ=0.44) 95CI [0.33-0.55] (p-value<0.001). Both the stress scores and sleep quality indices were not statistically significantly different across LUs. Gathered data and interpreted results showed that medical students suffering from stress are more likely to have poor sleep quality, which can lead to low academic performance and high susceptibility to chronic diseases, compared to those medical students with low levels of stress. Only being an LU IV [OR=1.38 95CI (0.036-4.625)] and LU V [OR=2.13 95CI (0.296-6.936)] student had increased odds of having poor sleep quality compared to LU III students. Caffeine intake, daytime nap, duty hours, clinical rotation, sex, and age were not associated with poor sleep quality. Conclusion: This study documents a statistically significant association between stress and poor sleep quality among LU III to LU VII UPCM students. A larger study covering multiple medical schools in the Philippines may be of merit for future investigations to generate nationwide data. Additional recommendations include: a) conducting a cross-sectional or a longitudinal study to detect changes in the characteristics of the population, b) observing the differences in the contributing factors at multiple points throughout the year, c) investigating the effect of dwelling set-up on sleep quality may also be investigated and d) determining if sleep quality affects the level of perceived stress of medical students.

Complications following laryngeal sacculectomy in brachycephalic dogs.

OBJECTIVES: To evaluate the effect of sacculectomy on the immediate postoperative complication rate in dogs affected with brachycephalic obstructive airway syndrome. MATERIALS AND METHODS: Retrospective review of clinical records of brachycephalic dogs with everted saccules that underwent surgery for brachycephalic obstructive airway syndrome between 2009 and 2014. Dogs were grouped as those having nares resection and staphylectomy only and those having nares resection, staphylectomy and laryngeal sacculectomy. Complications were scored as mild, moderate or severe. RESULTS: In total, 37 dogs were included in the sacculectomy group and 44 in the comparator group. Dogs that had undergone sacculectomy were more likely to develop postoperative complications, with 18 of 37 developing complications, nine of which were moderate to severe. In the group without sacculectomy, nine of 44 dogs developed complications, of which one was severe. Different breed distribution between groups might also impact this outcome. CLINICAL SIGNIFICANCE: The results suggest that sacculectomy might increase morbidity following brachycephalic airway surgery, but repeat studies are required to confirm this result. Further information is also required to determine whether the short-term risks of sacculectomy are outweighed by superior long-term functional outcome.

Relationship between brachycephalic airway syndrome and gastrointestinal signs in three breeds of dog.

OBJECTIVES: To assess the breed-specific prevalence of, and effects of corrective airway surgery on, gastrointestinal signs in French bulldogs, English bulldogs and pugs presenting with brachycephalic airway syndrome to a referral teaching hospital. MATERIALS AND METHODS: In this retrospective study, ptyalism, regurgitation and vomiting were graded at presentation using a previously established scoring system. Staphylectomy and nares resection were performed on all dogs. Gastrointestinal signs were re-assessed via telephone follow-up at least 6 weeks after surgery. RESULTS: Ninety-eight dogs were included: French bulldogs (n=43), English bulldogs (n=12) and pugs (n=43). Overall population prevalence of all gastrointestinal signs was 56%. Breed-specific prevalence for French bulldogs was 93%, English bulldogs 58% and pugs 16%. There was post-surgical clinical improvement in gastrointestinal signs for the whole study population, especially in French bulldogs. CLINICAL SIGNIFICANCE: The prevalence of gastrointestinal signs in dogs presenting with brachycephalic airway syndrome and improvement in these clinical signs following corrective surgery may vary between breeds.

Association of tricuspid annular plane systolic excursion with survival time in Boxer dogs with ventricular arrhythmias.

BACKGROUND: Tricuspid annular plane systolic excursion (TAPSE) is a useful estimate of right ventricular function in humans. Reference intervals for dogs have been generated, but the value of measuring TAPSE in other diseases, or investigating the association between TAPSE and outcome, is unknown. HYPOTHESIS: TAPSE is lower in Boxer dogs with ≥50 VPCs/24 h on Holter than in dogs with fewer ventricular ectopics, and lower TAPSE is associated with a shorter survival time. ANIMALS: Fifty Boxer dogs that presented for investigation of syncope or suspected arrhythmogenic right ventricular cardiomyopathy (ARVC) at a veterinary teaching hospital (2004-2011). METHODS: Retrospective study. Clinical records, Holter, and echocardiographic data were reviewed. TAPSE was measured in a blinded manner on stored echocardiographic cine-loops using anatomic M-mode. Outcome information was obtained and death was classified as cardiac or noncardiac. Survival analysis was performed using Kaplan-Meier curves and Cox proportional hazards models. RESULTS: TAPSE was lower in Boxers with ≥50 VPCs/24 h (13.9 ± 4.04 mm) than Boxers with <50 VPCs/24 h (16.8 ± 3.21 mm; P < .001). TAPSE <15.1 mm was associated with shorter cardiac survival time in all dogs (P = .004) and also in dogs without left ventricular dysfunction (P = .035). When controlling for other variables, including ventricular tachycardia on Holter and left ventricular systolic dysfunction, multivariable analysis showed that TAPSE remained an independent predictor of time to cardiac death (HR >4.09, 95%CI 1.15-16.9, P < .029). CONCLUSIONS AND CLINICAL IMPORTANCE: TAPSE offers prognostic value for Boxer dogs, including those with apparently normal systolic function and ≥50 VPCs/24 h on Holter analysis.

Retrospective evaluation of moderate-to-severe pulmonary hypertension in dogs naturally infected with Angiostrongylus vasorum.

OBJECTIVES: The outcome in dogs with pulmonary hypertension associated with natural Angiostrongylus vasorum infection is unclear. This study aimed to report long-term outcome of dogs with A. vasorum and pulmonary hypertension, and to evaluate factors associated with pulmonary hypertension development. It was hypothesised that dogs with pulmonary hypertension had a shorter survival time than dogs without pulmonary hypertension. METHODS: Retrospective review of clinical records of dogs diagnosed with A. vasorum. Dogs were classified as having or not having pulmonary hypertension based on clinical signs and imaging findings. Signalment, signs and outcome were recorded. DNA obtained from banked samples was genotyped for the PDE5a:E90K polymorphism, a possible factor in development of pulmonary hypertension. RESULTS: The proportion of dogs with moderate-to-severe pulmonary hypertension and A. vasorum infection in the study population was 14 · 6%. No difference in the population characteristics or PDE5a genotype was detected between dogs with and without pulmonary hypertension. Dogs with pulmonary hypertension had a significantly shorter survival time (P = 0 · 006) and a greater risk of death within 6 months of diagnosis (odds ratio 12 · 5, 95% confidence interval 2 · 1 to 74 · 9; P = 0 · 0053). CLINICAL SIGNIFICANCE: A. vasorum-associated pulmonary hypertension is an important problem in naturally infected dogs and has a negative effect upon survival.

Streptococcus bovis catheter infection and the short bowel syndrome.

Streptococcus bovis bacteremia has been associated with several gastrointestinal disorders, most notably carcinoma of the colon. This report describes a 57-year-old woman with short bowel syndrome in whom S. bovis bacteremia and an infection of an indwelling parenteral nutrition catheter developed. A barium enema revealed diverticula and a foreshortened small intestine. This case implicates the short bowel syndrome in the pathogenesis of S. bovis bacteremia and supports empiric antibiotic coverage for both skin flora and enteric pathogens in patients with Hickman catheter sepsis and known gastrointestinal pathologic conditions.

Rheumatoid nodules. Review of the spectrum of associated conditions and proposal of a new classification, with a report of four seronegative cases.

The literature relating to prevalence, characteristics, differential diagnosis, histologic features, pathogenesis, complications, and prognosis of rheumatoid nodules is tabulated and reviewed. The broad spectrum of conditions associated with rheumatoid nodules is discussed. A new classification of these clinical entities, reflecting disease characteristics and prognosis, is proposed. This classification is based on age, association or lack thereof with rheumatoid arthritis or rheumatic features, the presence or absence of rheumatoid factors, and the location of the rheumatoid nodules. Four cases of rheumatoid nodules in patients without rheumatoid factor are presented. Three patients had classic or definite rheumatoid arthritis, and one had palindromic rheumatism. In follow-ups lasting one to 15 years, significant permanent joint deformities, bony erosions, or extra-articular manifestations of rheumatoid arthritis have not developed in any of the patients. All have experienced significant periods of remission.

Role of intravenous cyclophosphamide in the treatment of severe neuropsychiatric systemic lupus erythematosus.

PURPOSE: We assessed the outcome of 31 patients with severe neuropsychiatric (NP) systemic lupus erythematosus (NPSLE) treated with intravenous cyclophosphamide (IV-CYC), and identified clinical predictors of response to therapy. METHODS: The authors performed a retrospective chart review and classified patients by NP manifestation and response to therapy as measured by serial anatomic imaging and neurodiagnostic studies coupled with clinical assessment of improvement. RESULTS: Neuropsychiatric manifestations occurred with the following frequencies: organic brain syndromes (OBS) 55%, stroke syndromes 35%, peripheral or mononeuropathy 32%, seizures 29%, psychiatric symptoms 26%, transverse myelitis 16%, cranial neuropathies 13%, other 16%. Most patients had multiple NP manifestations, with a median of two. Ninety percent of patients had failed therapy with corticosteroids with or without cytotoxic drugs prior to treatment with IV-CYC. Eight patients received synchronous plasmapheresis along with IV-CYC. After treatment with IV-CYC, NP deficits substantially improved in 61% (group I), stabilized in 29% (group S), and progressively deteriorated in 10% (group P). Patients in group I had significantly fewer NP manifestations than combined group S+P, two versus four, and a lower frequency of OBS, 37% versus 83%. CONCLUSION: Intravenous cyclophosphamide appears to be an effective treatment for some patients with severe NPSLE refractory to other forms of therapy. Higher number of NP manifestations and presence of OBS may predict poor outcome and identify a group of patients for whom early aggressive therapy may be indicated.

Treatment of children with posttraumatic transient loss of consciousness.

Recommendations for the treatment of asymptomatic children who have had a brief period of loss of consciousness due to blunt head trauma are anecdotal and vary greatly. The purpose of this study is to define the range of practice in treating children with uncomplicated loss of consciousness by determining: (1) the frequency of "routine" hospitalization for observation and (2) those criteria which, when present, result in hospitalization. A total of 957 pediatricians representing five groups of physicians responded to a nationwide questionnaire survey to determine current treatment practices for uncomplicated loss of consciousness. Of all directors of pediatric emergency rooms and pediatric chief residents, 44% routinely hospitalize all patients who have had loss of consciousness. Academic child neurologists and child neurologists in private practice hospitalize these patients least frequently, 29% and 31%, respectively (P less than 0.05). Of pediatricians in private practice, 38% admit all children with loss of consciousness. Pediatricians from all groups who do not routinely hospitalize all children with uncomplicated loss of consciousness showed similarity in the criteria they use for admission. These variables include: abnormal vital signs (97% to 100%), skull fracture (96% to 100%), suspicion of child abuse (93% to 100%), observation of a change in level of consciousness (92% to 99%), unreliable caretaker at home (91% to 98%), vomiting (90% to 99%), history of a change in level of consciousness (88% to 100%), duration of loss of consciousness (88% to 96%), seizure (77% to 94%), age of child (62% to 75%), child nearly back to normal (32% to 48%), dizziness (22% to 49%), witness of loss of consciousness not reliable (24% to 36%), headache (9% to 16%), and decision deferred to neurosurgeon (2% to 7%).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term safety and use-effectiveness of intrauterine devices.

The long-term safety and effectiveness of Lippes Loops, A, C, and D, Dalkon Shields, Saf-T-Coils, and Cu 7-200 intrauterine devices (IUDs) were evaluated on the basis of 670 insertions in 588 women. Ten-year life-table rates for the Lippes Loops C (291 first insertions) and D (213 first insertions) were evaluated. The Loop C was consistently associated with a significantly higher expulsion rate but lower pregnancy rate as compared with the Loop D. Over-all, the removal rates for these two IUDs were similar. The incidence of pelvic infection and abnormal Papanicolaou smears, the time from IUD removal to conception, pregnancy outcome, and the need for any surgery post-IUD insertion were evaluated for all IUDs and all segments of use.

Analysis of cefazolin in serum or urine.

A method was developed to determine cefazolin in serum or urine. The drug is extracted from serum or urine with ethyl acetate, separated by TLC, and determined by fluorescence quenching densitometry. The method was developed to study the pharmacokinetics of the compound in humans.

Comparison of the image quality of intravenous urograms using low-osmolar contrast media.

Almost equivalent, intravenous iodine doses of the three new low-osmolar contrast media, ioxaglate (Hexabrix), iopamidol (Niopam) and iohexol (Omnipaque) have been compared for image quality on the intravenous urogram. Generally good radiographic images were obtained. Iohexol gave better results for the nephrogram and pelvicalyceal distension compared with the other contrast media, but only the nephrogram results were statistically significant. Pyelographic density and ureteric distension and density were similar with all three contrast media. In patients where low-osmolality contrast media need to be used for intravenous urography, we suggest that iohexol gives the best radiographic images. Other factors, such as cost and the relative incidence of side-effects of the low-osmolar contrast media also need to be taken into consideration.

The prevalence and nature of back pain in an industrial complex: a questionnaire and radiographic and HLA analysis.

A questionnaire relating to presence and nature of back pain was distributed to all 10,150 employees (59% men) of an industrial complex. The questionnaire was returned by 2892 subjects (65% men). Of these, 1880 (65% of responders or 19% of total) reported a history of back pain. One hundred twenty-four described their back pain as insidious in onset, persisting for at least three months, developing at less than 40 years of age, being associated with morning stiffness, and showing improvement with exercise. Three hundred sixty-seven subjects scored four of these five features. Pelvic radiographs of 342 persons were available for blind evaluation. Sixteen patients (12 men) were shown to have definite ankylosing spondylitis (Grade III or IV sacroiliitis or HLA B27-associated Grade II sacroiliitis). Only one of these persons was known to have spondylitis. The majority of these symptomatic patients had been seen by both medical and nonmedical practitioners.

In vitro metabolism studies on oxamniquine and related compounds by chiral liquid chromatography.

A previously developed method based on alpha 1-acid glycoprotein for the resolution of the enantiomers of the Pfizer antischistosomal drug oxamniquine was used to examine possible enantioselectivity in the in vitro microsomal hydroxylation of a metabolic precursor, UK-3883, but was found to be limited by the poor operational stability of the analytical column ("EnantioPac") employed. As an alternative approach, a "Pirkle" covalently-bonded dinitrobenzoyl leucine column was used, with simple precolumn solute derivatization to the carbamate to improve chromatographic performance. The method allowed preliminary examination of the stereochemistry of the in vitro biotransformation, hydroxylation of UK-3883 to oxaminquine, which yielded evidence for substrate enantioselectivity in favour of the dextrorotatory enantiomer of UK-3883.

Clinical analysis of sampatrilat, a combined renal endopeptidase and angiotensin-converting enzyme inhibitor I: assay in plasma of human volunteers by atmospheric-pressure ionisation mass-spectrometry following derivatisation with BF3-methanol.

Sampatrilat is a dual inhibitor of angiotensin converting enzyme (ACE) and neutral endopeptidase (NEP) under development for the treatment of hypertension and congestive heart failure. In order to support the early clinical development (with oral administration and an expected low bioavailability), a sensitive and selective assay was required. A method for plasma was developed and validated employing HPLC APCI MS-MS. The plasma samples were extracted on solid-phase extraction cartridges, derivatised with BF3-methanol, diluted, extracted again and then subjected to HPLC APCI-MS-MS. Derivatisation was necessary because the two carboxyl group in the molecule prevented efficient ionisation in the heated nebuliser source. The calibration range was from 0.5 to 20 ng ml(-1) and the lower limit of quantification was 0.5 ng ml(-1). Imprecision and inaccuracy were determined on three separate occasions at three concentrations (0.5, 5 and 20 ng ml[-1]) and shown to be lower than 10% in every case.

Clinical analysis of sampatrilat, a combined renal endopeptidase and angiotensin-converting enzyme inhibitor II: assay in the plasma and urine of human volunteers by dissociation enhanced lanthanide fluorescence immunoassay (DELFIA).

Sampatrilat is a dual inhibitor of angiotensin converting enzyme (ACE) and neutral endopeptidase (NEP) under development for the treatment of hypertension and congestive heart failure. In order to support the early clinical development (with oral administration and an expected low bioavailability), a sensitive and selective assay was required. An HPLC-atmospheric-pressure chemical ionisation mass-spectrometric (HPLC-APCI-MS-MS) assay had been already validated (R.F. Venn et al., J. Pharm. Biomed. Anal., in press), but due to its low throughput an alternative method was sought. As the molecule is peptide-like and not metabolised, we believed the immunoassay approach was appropriate. Thus we developed an immunoassay for the compound using time-resolved fluorescence as an end-point (DELFIA) with lower limits of quantification of 0.2 ng ml(-1) for the plasma assay and 5 ng ml(-1) for the assay in urine. This assay is a 96-well plate based competitive immunoassay; the end-point is the determination of a (non-radioactive) europium label by time-resolved fluorimetry. Sampatrilat is labelled with chelated europium via isothiocyanate chemistry. The advantage of this assay is its extremely high throughput, allowing rapid analysis of many thousands of samples. The DELFIA method was successfully cross-validated with the HPLC-APCI-MS-MS method.

Measurement of the class III antidysrhythmic drug, UK-68,798, in plasma by radioimmunoassay.

A sensitive radioimmunoassay (RIA) for the specific determination of 1-(4-methanesulphonamidophenoxy)-2-[N-(4-methanesulphonamido -phenethyl)-N- methylamino]ethane (UK-68,798), a novel class III antidysrhythmic agent, in human plasma is described. Specific antisera were raised in sheep using desmesyl-UK-68,798-succinate-ovalbumin conjugate as the antigenic hapten carrier protein. The antisera produced exhibited high specificity for UK-68,798 compared with known metabolites from animals, other antidysrhythmic agents and co-administered drugs. Good correlation was found in a comparison of the RIA method with a high-performance liquid chromatography (HPLC) method (r = 0.997) and a 10-fold lower limit of determination was observed for the RIA method compared with the HPLC method (0.05 and 0.5 ng ml-1, respectively). The RIA method was applied to the analysis of UK-68,798 in plasma obtained from human volunteers receiving the compound.