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Biomedical subjects

T A Farrell

Publications and source records attributed to T A Farrell.

At least 19 recordsLinked to original sources
PubMed1999

Problem-based learning in ophthalmology: a pilot program for curricular renewal.

OBJECTIVES: To gain experience with problem-based learning as a demonstration project in a medical school's curriculum renewal effort and determine if using a single facilitator to circulate among the small groups would yield positive results. DESIGN: We developed 16 cases around 4 ophthalmic problems that were used in 3-hour small-group sessions during the Introduction to Clinical Medicine semester of the second-year curriculum. A single faculty member facilitated the small groups of 4 students each that were created by self-division at each of 5 sessions. SETTING: A state-supported large Midwestern medical school. PARTICIPANTS: All students (N = 75) enrolled in the Introduction to Clinical Medicine course prior to their standard introductory ophthalmology lectures. MAIN OUTCOME MEASURES: A 5-item pretest, related to each of that day's clinical problems, was administered at the beginning and again at the end of the session as a posttest. A satisfaction questionnaire with Likert-type questions was also completed by the students at the close of the session. RESULTS: Knowledge scores showed statistically significant gains with a mean of 1.7 points. Student satisfaction was very positive--85% stated that they learned more than they would have in the traditional format and 93% agreed that they enjoyed the problem-based learning format. CONCLUSIONS: A single facilitator successfully managed small groups of students in a modified problem-based learning format that produced significant knowledge gains and high student satisfaction. This positive experience was one of the factors that led to adoption of problem-based learning into the curriculum.

Education, Medical, Undergraduate↗
PubMed1999

Percutaneous biliary drainage in patients with nondilated intrahepatic bile ducts.

OBJECTIVE: We evaluated the technical success and complications of percutaneous transhepatic biliary drainage in patients with nondilated intrahepatic bile ducts. MATERIALS AND METHODS: Between January 1, 1996, and August 31, 1998, 130 percutaneous transhepatic biliary drainage procedures were performed on patients with nondilated intrahepatic bile ducts. This group comprised primarily patients who had received liver transplants or who had sustained iatrogenic bile duct injuries. Access in all procedures was performed using a one-step system consisting of a 21-gauge needle and an .018-inch guidewire. The technical success and complications of the procedures were evaluated. RESULTS: Percutaneous biliary drainage was successful in 117 (90%) of 130 attempts. In four patients, two attempts were required to place a drainage catheter. The overall complication rate was 9%. There were seven (5%) minor complications and five major complications (4%). No procedure-related deaths occurred. CONCLUSION: Percutaneous biliary drainage can be performed with a high success rate in patients with nondilated intrahepatic ducts. The incidence and types of complications in this population were similar to those reported in patients with intrahepatic ductal dilatation.

Adult↗
PubMed1995

Clinical significance of fetal choroid plexus cysts.

Choroid plexus (CP) cysts are commonly detected on routine mid-trimester ultrasound scan. When associated anomalies are detected, the risk is sufficient to justify an invasive diagnostic test such as amniocentesis. However, the risk when no associated anomalies are detected is much less well defined. This information is required to determine the appropriate management in cases of apparently isolated CP cysts. We thought the only way to resolve the difficulties in counselling prospective parents was to conduct a prospective study in a large unselected population. A registry of fetal CP cysts detected over 3 years in the Yorkshire Region was compiled and we identified 524 CP cysts. These cases were then amalgamated and analysed with 1361 cases from prospective studies reported in the world English literature and a further 71 unpublished cases identified from a 2 year prospective series from Ninewells Hospital, Dundee. The risk of chromosomal abnormalities was 1 in 150 (95% CI 1 in 85, 1 in 261) when no fetal anatomic abnormalities, apart from the CP cysts themselves, were detected antenatally. The risk increased to approximately 1 in 3 if any other associated ultrasound abnormalities were detected antenatally. The risk did not appear to be related to whether or not cyst size diminished as gestation progresses, whether they were unilateral or bilateral, and whether they were small or large in size (60-80% < 10 mm). 76% of aneuploidic cases were trisomy 18 and 17% were trisomy 21. The risk of Down's syndrome in fetuses with CP cysts but no other anomalies detected antenatally is 1 in 880. The probability of a chromosomal abnormality is high when CP cysts are associated with any other antenatally detected anomaly, indicating a clear need to offering amniocentesis. The predictive value is much lower when no other anomalies are detected. In such cases, it is probably advisable to regard CP cysts as an indication for detailed ultrasound assessment, rather than invasive testing.

Brain Diseases↗
PubMed1995

Umbilical cord blood gas analysis; a comparison of two simple methods of sample storage.

Umbilical cord vessel acid-base analysis is increasingly employed as an end-point in the study of ante-partum and intra-partum care. Delay in processing the sample can results in erroneous values as a result of gaseous diffusion and continuing metabolism. The effect of delay was investigated for samples stored in heparinized syringes at room temperature and simultaneously stored samples in double clamped cord segments. Small, but statistically significant changes were seen for pH, base deficit and PCO2 over 30 min. Storage in the syringe results in the most reliable values for pH and base deficit, whereas the cord segments showed no changes in PO2 and PCO2.

Blood Gas Analysis↗
PubMed1995

Mucinous cystic tumor of the pancreas: an analysis of FNA characteristics with an emphasis on the spectrum of malignancy associated features.

Previously, pancreatic mucinous cystic tumors were classified as either benign (cystadenoma) or malignant (cystadenocarcinoma). Descriptions of the fine-needle aspiration (FNA) findings of these neoplasms have heretofore emphasized malignant cytologic characteristics. In the following, we present a summary of a study of FNA characteristics from ten patients with cystic mucinous neoplasms, four of whom have correlating histologic material. In this study, we found a spectrum of cytologic features ranging from completely benign appearing to obviously malignant. We discuss cystic mucinous pancreatic tumors and the associated FNA findings helpful in diagnosis and categorization of these neoplasms. Also, we suggest the inclusion of a new entity in the mucinous neoplasm category.

Adenoma↗
PubMed1995

Spontaneously changing gravid cervix: clinical implications and prognostic features.

PURPOSE: To assess the implications of spontaneous changes in the length and configuration of the gravid cervix during a single ultrasound (US) examination and to correlate specific cervical dimensions with pregnancy outcome. MATERIALS AND METHODS: Sonograms in 27 pregnant patients with a spontaneously changing cervix were studied prospectively. The length and width of cervical funneling and the length of intact cervix caudal to the funneling were measured when the cervical dimensions were most normal and most abnormal. Sonographic measurements were correlated with clinical and delivery data. RESULTS: Twenty patients delivered preterm, although only six delivered within a week of the US examination. Wider funneling of the internal os and a shorter segment of intact cervix caudal to the funneling both correlated with an increased likelihood of preterm delivery. CONCLUSION: Most patients with a spontaneously changing cervix deliver preterm. Measurements obtained when the cervix appears most abnormal are most predictive of early delivery.

Adolescent↗
PubMed1994

Fetal lateral ventricles: reassessment of normal values for atrial diameter at US.

PURPOSE: To assess the normal range of cerebral ventricular atrial diameters during the second and third trimesters of pregnancy. MATERIALS AND METHODS: The transverse diameter of the atrium of the lateral ventricle was prospectively measured in 739 consecutive antenatal ultrasound examinations by positioning electronic calipers on the luminal margins of the ventricular wall, perpendicular to the long axis of the ventricle. RESULTS: The mean ventricular atrial diameter for the combined group of all 739 studies was 5.4 mm +/- 1.2 (standard deviation). The transverse diameter of the ventricular atrium did not progressively increase with advancing gestational age. All fetuses younger than 17 menstrual weeks had ventricular atrial diameters less than 8 mm. Four fetuses had ventricular diameters of 10 mm or greater. CONCLUSION: A reasonable upper limit of normal for transverse atrial diameter for gestational age of 25 weeks and above appears to be 10 mm. Prior to 25 weeks, diameters over 8 mm are unusual in the healthy fetus and signal the need for a detailed evaluation of fetal anatomy.

Cerebral Ventricles↗
PubMed1993

Abdominal ultrasonography following laparoscopic cholecystectomy: a prospective study.

Laparoscopic cholecystectomy has gained widespread acceptance as the operation of choice for symptomatic gall-stones. We prospectively performed ultrasonography on 100 consecutive patients after laparoscopic cholecystectomy to determine the effect of this procedure on common bile duct diameter. This study also examines the incidence and clinical significance of intra-abdominal fluid collections after laparoscopic cholecystectomy. Our results show that 24% of patients had dilatation of the common duct (greater than 6 mm) when scanned 48 h post-operatively. The incidence of dilated common ducts fell to 9% when the patients were scanned 1 month later. This transient dilatation of the common duct, occurring post-operatively, has not been previously described. Intra-abdominal fluid collections were demonstrated in 10% of our patients but were clinically significant in only 1%. This study suggests that routine ultrasonography has a low yield immediately after laparoscopic cholecystectomy.

Abdomen↗
PubMed1991

Phenylephrine prodrug. Report of clinical trials.

The authors evaluated the mydriatic effect of phenylephrine oxazolidine prodrug, a lipophilic sympathomimetic that undergoes hydrolysis to phenylephrine as it passes through the cornea and aqueous humor. Double-masked clinical trials were performed randomizing 66 healthy subjects to receive either the silicone vehicle as a placebo, 10% viscous phenylephrine hydrochloride (HCl), or prodrug in 0.25%, 0.50%, or 1.0% concentrations. A mean horizontal pupillary diameter of 8.8 mm was achieved in 30 minutes in those receiving 1% prodrug versus 6.5 mm obtained at 30 minutes with 10% viscous phenylephrine HCl. Statistically, this difference was highly significant at P less than or equal to 0.0001. There were minimal systemic or ocular adverse effects from any preparation.

Administration, Topical↗
PubMed1991

Minimizing the systemic effects of glaucoma medications.

Glaucoma accounts for over 3 million office treatment visits annually. While effective, all antiglaucoma drugs, both topical and systemic, have potential and sometimes fatal side effects. Knowledge of the systemic sequelae can prompt early recognition and appropriate adjustment of treatment. Simple preventive measures can be offered to patients which will reduce their chance of systemic absorption of ocularly applied drugs.

Aged↗
PubMed1983

Sensitive and selective assay for adenosine using high-pressure liquid chromatography with fluorometry.

A new method for quantitation of adenosine was tested in canine myocardial extracts. The method involves incubation of the extract with chloroacetaldehyde to form the fluorescing adenosine derivative 1, N6-ethenoadenosine. The ethenoadenosine is separated by high-pressure liquid chromatography (HPLC) and quantitated by fluorometry. Experiments demonstrated that 1) the method is selective for adenosine, 2) fluorescence peak height is linearly related to the quantity of ethenoadenosine, and 3) adenosine in the extract is quantitatively converted to ethenoadenosine by the incubation procedure. Also, within the range of adenosine concentrations seen in five extracts, estimates of myocardial adenosine content with the fluorometric method were nearly identical to those using the more routine technique of HPLC with direct detection by ultraviolet (UV) absorption. A primary advantage of the fluorometric method is its greater sensitivity. As little as 0.50 pmol on the column could be quantitated by fluorescence, compared with approximately 20 pmol with UV absorption. Because of the greater sensitivity, the fluorometric method should be more easily applied to samples with smaller adenosine concentrations.

Adenine↗
PubMed1983

Evidence that a coronary alpha-adrenergic tone limits myocardial blood flow and oxygenation in acute hemorrhagic hypotension.

In 17 anesthetized dogs, left coronary blood flow (LCBF), left ventricular oxygen extraction [(a-v)O2], and myocardial oxygen consumption (MVO2) were monitored. Coronary perfusion pressure (CPP) was varied over a wide range by hemorrhage, and the effects of alpha-adrenergic blockade elicited by intracoronary phenoxybenzamine were assessed. During normotension (CPP greater than 80 mm Hg), blockade increased LCBF by 31 +/- 6 (SEM) %, but (a-v)O2 was substantially decreased so that MVO2 was increased by only 13 +/- 3%. At lower levels of CPP, the absolute increase in LCBF caused by blockade was similar to that during normotension, but because of the reduced preblockade LCBF, the percentage increase was greater. Thus, at a CPP of 50-80 mm Hg, LCBF increased by 41 +/- 15%, and at CPP less than 50 mm Hg, LCBF increased by 47 +/- 11% (P less than 0.05 compared to percentage of change during normotension). Furthermore, during hypotension the increase in LCBF after blockade was not accompanied by a large decrease in (a-v)O2. Consequently, in severe hypotension (CCP less than 50 mm Hg), both the absolute increase and the percentage increase in MVO2 was significantly greater than during normotension. These data suggest that during hypotension, especially severe hypotension, an alpha-adrenergic tone in the coronary circulation limits coronary flow and myocardial oxygenation.

Animals↗
PubMed1981

Complete ophthalmoplegia secondary to amyloidosis associated with multiple myeloma.

Total ophthalmoplegia associated with biopsy-proven amyloid infiltration of the extraocular muscles developed in a 60-year-old man with multiple myeloma. Amyloid was also found in biopsy specimens of the conjunctiva and eyelid papules. The patient also had eyelid purpura, keratitis sicca, and pupillary abnormalities. Treating the multiple myeloma had no effect on the ophthalmoplegia. Physicians should be aware that ophthalmoplegia associated with amyloidosis may indicate an underlying myeloma rather than primary systemic amyloidosis.

Amyloidosis↗