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Biomedical subjects

R G Buckley

Publications and source records attributed to R G Buckley.

16 recordsLinked to original sources
PubMed1999

History and physical examination to estimate the risk of ectopic pregnancy: validation of a clinical prediction model.

STUDY OBJECTIVE: To prospectively validate a clinical prediction model for ectopic pregnancy (EP). METHODS: Prospective cohort with 14-month derivation and 12-month validation phases. All hemodynamically stable, first-trimester patients with abdominal pain or vaginal bleeding who presented to a military teaching hospital emergency department underwent follow-up until an outcome of intrauterine pregnancy (IUP) or EP was established. Patients were separated into the high-risk group, defined as having either peritoneal signs or definite cervical motion tenderness; intermediate-risk group, defined as the presence of pain or tenderness, other than midline cramping, plus absence of fetal heart tones, and absence of tissue visible at the cervical os; and low-risk group (neither high- nor intermediate-risk) using recursive partitioning. RESULTS: Summarizing both phases, 915 patients had 845 (93%) IUPs and 70 (7.6%) EPs, with 18 (1.9%) lost to follow-up. The clinical prediction model classified 75 (8.2%) into the high-risk group (sensitivity 31%, 95% confidence interval [CI] 21% to 44%; specificity 94%, 95% CI 92% to 95%); and 644 (70%) in the intermediate-risk group (sensitivity 98%, 95% CI 89% to 100%; specificity 25%, 95% CI 22% to 29%). The remaining 196 (21%) patients who met neither high-risk nor intermediate-risk criteria were classified into the low-risk group. On the basis of EP prevalence of 7.7%, the risk of EP was less than 1% (95% CI 0% to 3%) for the low-risk group, 7% (95% CI 5% to 10%) for the intermediate-risk group, and 29% (95% CI 19% to 41%) for the high-risk group. CONCLUSION: This clinical prediction model is useful for estimating the risk of EP in first-trimester patients, particularly when ancillary testing is equivocal or not readily available.

Adult↗
PubMed1999

The risk of appendiceal rupture based on hospital admission source.

OBJECTIVE: To determine whether admission source is a potential risk factor for appendiceal rupture. METHODS: Administrative data were obtained from the California Office of Statewide Health Planning and Development for all patients in San Diego County with the primary diagnosis of appendicitis during 1993. The appendiceal rupture ratio was defined as those coded as ruptured (ICD-9-CM codes 540.0 and 540.1) divided by both ruptured and non-ruptured cases (540.9). The odds ratio of appendiceal rupture from routine outpatient office or clinic venues vs those admitted through the ED were calculated using multivariate logistic regression analysis to adjust for age, sex, race, comorbidity, insurance status, and home address to hospital proximity. RESULTS: There were a total of 1,906 patients, of whom 663 (34.8%) had appendiceal ruptures. Of the 1,360 (71.4%) admitted from the ED, 422 (31.0%) had ruptures, compared with 211 (43.3%) of the 487 admitted from outpatient sources (p < 0.0001). Patients with appendicitis directly admitted from outpatient sources were more likely to be complicated by appendiceal rupture than were those admitted through the hospital ED (adjusted odds ratio 1.62, 95% CI = 1.28 to 2.05, p < 0.0001). CONCLUSION: Patients with appendicitis admitted from outpatient sources are more likely to have appendiceal rupture than are those admitted from the ED.

Adolescent↗
PubMed1998

Prospective comparison of unenhanced spiral computed tomography and intravenous urogram in the evaluation of acute flank pain.

OBJECTIVES: To prospectively compare the diagnostic ability of unenhanced spiral computed tomography (NCCT) and intravenous urogram (IVU) in the evaluation of adults with acute flank pain. METHODS: After giving informed consent, 106 adult patients with acute flank pain suspected of having urolithiasis underwent NCCT followed by IVU. Subsequent follow-up was scheduled within 72 hours in the Urology Clinic. Each NCCT was read by a single radiologist who was unaware of clinical history and IVU results. Each IVU was read by a different radiologist who was unaware of clinical history and NCCT results. Sensitivity, specificity, and positive and negative predictive values were determined for NCCT and IVU. RESULTS: The diagnosis of ureterolithiasis was defined as unequivocal evidence of urolithiasis on either NCCT or IVP. Seventy-five of 106 patients evaluated were diagnosed with ureterolithiasis. Clinical follow-up was available in 74 (98%) stone patients and in 31 (100%) of 31 non-stone patients. In 72 of the 75 patients diagnosed with ureteral calculi, the NCCT made the diagnosis. IVU made the diagnosis in 65 of the 75 patients. Of the 31 patients without ureterolithiasis, the NCCT was negative in all cases. IVU was negative in 29 of the 31 cases. Unenhanced spiral CT was 96% sensitive and 100% specific (P <0.001). IVU was 87% sensitive and 94% specific (P <0.001). Compared with IVU, using the log odds ratio and Fisher's exact test, NCCT was significantly better able to predict the presence of urolithiasis (P=0.015). CONCLUSIONS: NCCT accurately diagnoses ureterolithiasis in patients presenting with acute flank pain. NCCT is significantly better than IVU in determining the presence of urolithiasis.

Acute Disease↗
PubMed1998

Derivation of a clinical prediction model for the emergency department diagnosis of ectopic pregnancy.

OBJECTIVE: To derive a clinical prediction model for estimating the pretest probability of ectopic pregnancy in ED patients with first-trimester abdominal pain or vaginal bleeding. METHODS: All hemodynamically stable first-trimester patients presenting to the ED of a tertiary care military teaching hospital over a 14-month period with a chief complaint of abdominal pain and/or vaginal bleeding had clinical data coded prior to determining outcome. They were then followed longitudinally until a criterion standard pregnancy outcome was established. RESULTS: Of the 486 patients enrolled, 280 (58%) had viable intrauterine pregnancies, 167 (34%) had nonviable intrauterine pregnancies, and 39 (8%) had ectopic pregnancies. Using a recursive partitioning model, a high-risk group was derived (that was separated from intermediate and low-risk groups), consisting of patients with abdominal peritoneal signs or definite cervical motion tenderness, with a sensitivity of 31% (95% CI: 17-48%), a specificity of 93% (95% CI: 90-95%), a positive likelihood ratio of 4.3, and a negative likelihood ratio of 0.74. A low-risk group, consisting of patients with either fetal heart tones or tissue at the cervical os, or the absence of pain other than midline menstrual-like cramping and lacking any pelvic tenderness, was differentiated from an intermediate-risk group, with a sensitivity of 96% (95% CI: 81-100%), a specificity of 22% (95% CI: 18-26%), a positive likelihood ratio of 1.2, and a negative likelihood ratio of 0.17. CONCLUSION: A clinical prediction model for estimating the probability of ectopic pregnancy in ED patients has been derived. It may prove to have practical clinical application for estimating pretest probability of ectopic pregnancy as well as assisting in medical decision making when laboratory and ultrasonographic findings are nondiagnostic. Clinical application should await prospective validation in an independent sample.

Abdominal Pain↗
PubMed1996

Antitumor properties of some 2-[(dimethylamino)methyl]phenylgold(III) complexes.

Four analogues of the gold(III) complex [AuCl2(damp)] (1) (damp = 2-[(dimethylamino)methyl]phenyl) have been evaluated for antitumor activity. The compounds have structural features in common with cisplatin which was included as a comparison in the study. In vitro, against a panel of cell lines established from tumors of different tissue types, the gold complexes showed broadly similar growth inhibitory properties with some selectivity to the HT1376 bladder cell line. In a panel of human ovarian carcinoma cell lines, non-cross-resistance to cisplatin was observed, for the complexes, in an acquired cisplatin-resistant line. In vivo, using subcutaneously implanted xenografts derived from the HT1376 bladder and CH1 ovarian cell lines, [Au(acetato)2(damp)] (3) and [Au(malonato)(damp)] (5) (administered intraperitoneally) gave significant tumor inhibition. Mechanistic studies performed with compound 3 showed marked differences to cisplatin. Thus, much higher concentrations of the gold compound were required to affect Col E1 plasmid mobility, and an alkaline elution study showed that 3 did not cause interstrand DNA cross-links in SK-OV-3 cells. Exposure of SK-OV-3 cells to 3 induced only relatively minor changes in cell cycle distribution. Furthermore 3 was only marginally active in vivo against the cisplatin-sensitive murine ADJ/PC6 plasmacytoma. In summary, the gold-(III) complexes 3 and 5 exhibited selective cytotoxicity in vitro and showed in vivo antitumor activity against human carcinoma xenografts. Also, although 3 has some structural similarity to cisplatin, its mode of action appears to be different.

Animals↗
PubMed1996

Reliability of subjective fever in triage of adult patients.

STUDY OBJECTIVE: To determine whether a historical complaint of fever is predictive of fever on emergency department triage. METHODS: We prospectively questioned 651 ambulatory adult patients in a military tertiary care emergency department as to whether they had fever before oral temperature was taken. Fever was defined as a temperature of 38 degrees C (100.4 degrees F) or greater. RESULTS: Sensitivity and specificity were 84% (95% confidence interval [CI], 71% to 95%) and 83% (95% CI, 80% to 86%), respectively. The prevalence of objective fever was 6.4%, yielding positive and negative predictive values of 25% (95% CI, 18% to 32%) and 99% (95% CI, 93% to 100%), respectively. Overall accuracy was 83% (95% CI, 80% to 86%). CONCLUSION: In this study, outpatients were fairly accurate in predicting fever. However, in an outpatient population with a low overall prevalence of objective fever, the predictive value of a complaint of fever representing an objective fever remained low. Therefore the complaint of subjective fever should be interpreted with caution when it is used to support a given diagnosis in an ambulatory care setting.

Adolescent↗
PubMed1994

The pulse oximetry gap in carbon monoxide intoxication.

STUDY OBJECTIVE: Pulse oximetry has been reported to be falsely elevated in the presence of carbon monoxide (CO). However, the degree to which pulse oximetry overestimates measured oxyhemoglobin saturation (O2Hb) has not been investigated in patients with CO exposure. This study quantifies the effect of CO on pulse oximetry and O2Hb in a series of patients with elevated carboxyhemoglobin (COHb) levels. METHODS: A prospective case series of 25 pulse oximetry measurements, with concurrent arterial blood gas sampling, were obtained on 16 adults with CO exposure. RESULTS: COHb levels (mean, 16.1%; SD, 11.6%; range, 2.2% to 44%) did not significantly correlate with pulse oximetry saturation (mean, 97.7%; SD, 1.5%; range 96% to 100%) (r = .45; P = .1 [NS]). Compared with COHb, a pulse oximetry gap (mean, 17.5%; SD, 1.5%; range, 2.3% to 42%), defined as pulse oximetry saturation minus O2Hb, yielded a linear regression model: pulse oximetry gap = 1.82 + 0.94 x COHb (SEM = 0.07; F = 204; R2 = .90; P < .0001). CONCLUSION: Oxygen saturation as measured by pulse oximetry failed to decrease to less than 96% despite COHb levels as high as 44%. Regression between the pulse oximetry gap and COHb suggests that pulse oximetry overestimates O2Hb by the amount of COHb present. Pulse oximetry is unreliable in estimating O2Hb saturation in CO-exposed patients and should be interpreted with caution when used to estimate oxygen saturation in smokers.

Adult↗
PubMed1988

Tumour localization using monoclonal antibodies. II. Biodistribution of A5B7/111indium chelates.

The anti-CEA antibody A5B7 has been conjugated with the chelating agents DTPA and DHDE. Radioimmunoassay and FPLC studies have shown that the conjugation procedure has not impaired the CEA binding ability of the antibody or induced aggregate formation. Biodistributions of the 111In-labelled conjugates have been carried out in nude mice bearing the human colon carcinoma xenograft LS174T. The results show favourable tumour-to-tissue ratios for the DTPA conjugate.

Animals↗
PubMed1986

A comparative distribution study of 111In-labeled DTPA and TTHA monoclonal antibody conjugates in a choriocarcinoma xenograft model.

Conjugates of the chelating agents DTPA and TTHA with a monoclonal anti-HCG were prepared. The tissue distribution of the 111In-labeled conjugates and also 111In-citrate was studied in mice bearing human choriocarcinoma xenografts. The antibody conjugates both gave high liver and spleen radionuclide accumulation. Elevated femur levels were observed for the TTHA conjugate and 111In-citrate. Generally the DTPA conjugate showed the highest tumor/tissue ratios, although its tumor/blood ratio was lower than the other two materials. The results infer that the DTPA conjugate has the greatest utility as an imaging agent but that it would require a background subtraction technique.

Animals↗
PubMed1986

The potential of carboxypeptidase G2-antibody conjugates as anti-tumour agents. I. Preparation of antihuman chorionic gonadotrophin-carboxypeptidase G2 and cytotoxicity of the conjugate against JAR choriocarcinoma cells in vitro.

Carboxypeptidase G2, a zinc metalloenzyme isolated from Pseudomonas sp. strain RS-16, which catalyses the hydrolytic cleavage of reduced and non-reduced folates to pteroates and L-glutamate, has been linked to a monoclonal antibody (W14A) raised to human chorionic gonadotrophin. The coupling efficiency and retention of antibody and enzymatic activities are compared for three separate methods of preparing 1:1 conjugates. Preliminary in vitro studies on the cytotoxicity of the free enzyme and the conjugated enzyme towards JAR choriocarcinoma cells are reported. Despite the limitations of the in vitro model, it could be demonstrated that a significant proportion of 10(6) choriocarcinoma cells lost viability when exposed to either free or conjugated enzyme for 72 hours at concentrations of carboxypeptidase G2 of 1-3 units ml-1 of medium.

Antibodies, Monoclonal↗
PubMed1984

Preparation and properties of mouse monoclonal antibody (W14A) to human chorionic gonadotropin.

A mouse monoclonal antibody, W14A, has been prepared which reacts with intact human chorionic gonadotropin and its beta-subunit, showing less than 2% cross-reactivity towards the alpha-subunit and 0.5% cross-reactivity towards the beta-subunit of luteinizing hormone. The reagent is suitable for the radioimmunolocalization of choriocarcinoma and trophoblastic teratoma in humans. A preliminary radioimmunoassay has been developed.

Animals↗
PubMed1984

An efficient method for labelling antibodies with 111In.

Using a new method, rabbit IgG and a monoclonal antibody have been conjugated with the chelating agent DTPA. This was accomplished with reaction conditions that should entail lower antibody damage than existing methods. Gel filtration of the 111In-labelled antibody conjugate indicated minimal damage to the antibody and radioimmunoassay showed no significant change in its immunological activity.

Antibodies↗
PubMedDate not supplied

Comparison of two colorimetric assays as cytotoxicity endpoints for an in vitro screen for antitumour agents.

Two colorimetric assays, MTT and SRB, were compared as cytotoxicity endpoints. They were evaluated against four anti-cancer drugs and seven human tumour cell lines, results were analyzed by ANOVA. Both assays gave a linear response with respect to cell number. The cell lines exhibited differential cytotoxicity to the cancer drugs. Both assays gave similar dose/response curves with the MTT assay giving generally higher IC50 values than the SRB assay. Similar cytotoxicity profiles were obtained for each drug across the cell line panel with the two assays. Whilst both assays are suitable as cytotoxicity endpoints the SRB assay is recommended.

Analysis of Variance↗