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Biomedical subjects

L Collins

Publications and source records attributed to L Collins.

At least 37 records · Page 2Linked to original sources
PubMed2000

Tracheal intubation of outpatients with and without muscle relaxants.

PURPOSE: To compare intubating conditions and postoperative myalgias in outpatients after intubation with propofol/alfentanil compared with propofol/alfentanil/succinylcholine with and without precurarisation with d-tubocurarine. METHODS: 144 ASA I-II ambulatory patients for dental extraction under anesthesia were studied. Subjects received either 3 mg d-tubocurarine (Group II) or saline (Groups I, III) i.v. prior to induction of anesthesia with 20 microg x kg(-1) alfentanil and 2.5 mg x kg(-1) propofol followed by 1.5 mg x kg(-1) succinylcholine (II and III) or saline 0.9% (I) for muscle relaxation. The ease of airway management and the postoperative incidence, severity and distribution of muscle pains were examined. RESULTS: Intubation was successful in all patients and there were no differences in jaw mobility, ease of bag-mask ventilation, visualization of the vocal cords or cord position. Limb movement was more common during intubation in Group I (37.5%) than in Group III (8.3%) or Group II (2%), P < 0.05. At home, VAS scores for myalgia were higher in Group III than in Group I and II. Neck myalgia was more common in Group II (72%) than in Groups II (44%) and I (41%), P < 0.05. Myalgias were also more common in Group III patients (P < 0.05). CONCLUSION: Acceptable intubating conditions were achieved with propofol and alfentanil alone. Succinylcholine reduced limb movement during intubation but was associated with postoperative myalgias for up to five days. Precurarisation with tubocurarine reduced the severity of succinylcholine myalgia.

Adolescent↗
PubMed2000

Rom-1 is required for rod photoreceptor viability and the regulation of disk morphogenesis.

The homologous membrane proteins Rom-1 and peripherin-2 are localized to the disk rims of photoreceptor outer segments (OSs), where they associate as tetramers and larger oligomers. Disk rims are thought to be critical for disk morphogenesis, OS renewal and the maintenance of OS structure, but the molecules which regulate these processes are unknown. Although peripherin-2 is known to be required for OS formation (because Prph2-/- mice do not form OSs; ref. 6), and mutations in RDS (the human homologue of Prph2) cause retinal degeneration, the relationship of Rom-1 to these processes is uncertain. Here we show that Rom1-/- mice form OSs in which peripherin-2 homotetramers are localized to the disk rims, indicating that peripherin-2 alone is sufficient for both disk and OS morphogenesis. The disks produced in Rom1-/- mice were large, rod OSs were highly disorganized (a phenotype which largely normalized with age) and rod photoreceptors died slowly by apoptosis. Furthermore, the maximal photoresponse of Rom1-/- rod photoreceptors was lower than that of controls. We conclude that Rom-1 is required for the regulation of disk morphogenesis and the viability of mammalian rod photoreceptors, and that mutations in human ROM1 may cause recessive photoreceptor degeneration.

Animals↗
PubMed1999

Predictors of local recurrence following excision alone for ductal carcinoma in situ.

BACKGROUND: The treatment of ductal carcinoma in situ (DCIS) remains controversial, particularly in regard to the selection of patients who may be appropriately treated with wide excision alone. To help identify such patients, the authors assessed prognostic factors for local recurrence in patients with DCIS treated with excision alone. METHODS: The study population consisted of 59 patients diagnosed with DCIS between 1985 and 1990. All had been treated with excision alone, had their histologic slides available for re-review by a study pathologist, and had negative margins of excision on review. The median age at diagnosis was 54 years, and the median follow-up time was 95.5 months. Ninety-six percent presented with mammographic findings only; all patients had a reexcision. The size of the DCIS was assessed by the total number of low-power fields (LPF) in which DCIS was present (median LPF = 5). RESULTS: Ten patients experienced a local recurrence (LR) at 5-132 months (median, 37 months) after excision. The actuarial 5-year LR rate was 10%. Four of the recurrences were invasive carcinomas, and 6 were DCIS. No patients have developed metastatic disease or have died of disease. Lesion size >5 LPF was the only significant prognostic factor for local recurrence on univariate analysis (3% vs. 17% for < or = 5 vs. > or = 5 LPF, P = 0.02) and in proportional hazards models. Although patients with nuclear Grade 3 lesions had a higher LR rate than those with nuclear Grade 1 and 2 lesions (18% vs. 6% and 5%, respectively) and patients with close margins (< or = 1 mm) had a higher LR rate than patients with negative margins (>1 mm) (25% vs. 8%), these differences did not reach statistical significance. Among the 19 cases with margins negative by more than 1 mm, lesion size < or = 5 LPF, and nuclear Grade 1 or 2, there were no LRs; by contrast, the remaining 40 patients had a 5-year actuarial LR rate of 15% (P = 0.08). CONCLUSIONS: Lesion size was the only statistically significant prognostic factor for local recurrence in this series of patients with DCIS treated with excision alone. Other factors, such as margin status and nuclear grade, may also be useful in the identification of patients with DCIS who can be managed with excision alone. However, the most reliable and reproducible method of assessing these factors and the best way to combine them have not been determined.

Adult↗
PubMed1999

Impact of a regional anesthesia analgesia program for outpatient foot surgery.

PURPOSE: To examine the effects of a Regional Anesthesia and Analgesia (RAA) program for outpatient foot surgery in an outpatient unit. METHODS: The RAA program was implemented in our Surgical Day Care Center (SDCC) in 1992-93. Fifty charts were randomly selected for each of two periods, 1990 (pre-program) and 1995 (post-program). One surgeon operated on all patients. Preoperative, intraoperative and postoperative information collected included demographic data, block type, analgesic requirements, nursing visits and complications. A time analysis of the perioperative course was also performed. RESULTS: The use of regional block increased from 2% to 82% as a result of the RAA program. This was not accompanied by a change in operating room efficiency (anesthetic time, preparation time, exit time). Patient stay in the PACU and discharge lounge was reduced by a mean difference of 7 min (Upper 95% CI = 24 min) and fentanyl consumption in the OR was reduced by 35 microg (95% CI = -8, -62 microg). The number of patients who required > 1 < 4 nursing visits for analgesia administration in the PACU decreased from 17 to 9 after program implementation. CONCLUSIONS: Regional anesthesia is more likely to be offered to outpatients if it is introduced as a formal RAA program. Such a program did not have a negative impact on operating room efficiency and was beneficial in reducing patient stay in the PACU and discharge lounge. Facility discharge processes may need to be modified to obtain the maximum benefits from such RAA programs.

Adolescent↗
PubMed1999

Chromosome 9 monosomy by fluorescence in situ hybridization of bladder irrigation specimens is predictive of tumor recurrence.

PURPOSE: Bladder irrigation specimens are effective for sampling the urothelium for detection of recurrent bladder cancer. These specimens can be evaluated by cytology or quantitative techniques. Proliferation and ploidy changes are readily detected using deoxyribonucleic acid (DNA) cytometry. Tumor associated chromosomal aberrations can be assayed using fluorescence in situ hybridization (FISH). The prognostic values of DNA cytometry, and chromosome 9 and 9p21 FISH on exfoliated cells from bladder irrigation specimens from 61 bladder cancer patients were evaluated. MATERIALS AND METHODS: A total of 61 consecutive bladder irrigation specimens were obtained during cystoscopy. DNA cytometry was performed by image analysis. FISH was performed using a centromeric chromosome 9 probe and a cosmid contig (COSp16) probe to the CDKN2A/p16 tumor suppressor region of 9p21. Proportional hazards regression analysis was performed with statistical software to test the predictor variables of initial patient status (presence of tumor), COSp16 fraction (the proportion of COSp16 signals relative to centromeric probe signals), monosomic and hyperdisomic fractions of the chromosome 9 probe, and hyperdiploid fraction from DNA cytometry. Median time to recurrence was calculated using statistical software survival analysis. RESULTS: Initial patient status and monosomy of chromosome 9 were predictive of bladder cancer recurrence (p <0.0001 and p = 0.0073, respectively). The 11 patients with chromosome 9 monosomy fractions greater than 15% and a visible tumor had a median time to recurrence of 105 days. In contrast, only 8 of the 25 patients with chromosome 9 monosomy fractions less than 15% and no visible tumor had recurrence within 560 days. Median time to recurrence was 185 days for 6 patients with chromosome 9 monosomy fractions greater than 15% and no visible tumor, and 225 for 19 with chromosome 9 monosomy fractions less than 15% and a visible tumor. Hyperdiploid fraction was suggestive but not predictive of bladder cancer recurrence (p = 0.078). COSp16 and hyperdisomic fractions were not predictive of bladder tumor recurrence (p = 0.11 and p = 0.30, respectively). CONCLUSIONS: Chromosome 9 monosomy by FISH was predictive of bladder tumor recurrence. Furthermore, our findings support the hypothesis that losses of tumor suppressor genes on chromosome 9 are critical, perhaps initiating genetic events in bladder cancer.

Adult↗
PubMed1999

Quantitative genetic variation for oviposition preference with respect to phenylthiocarbamide in Drosophila melanogaster.

Seven isogenic strains of Drosophila melanogaster were assayed for oviposition preference on food with phenylthiocarbamide (PTC) versus plain food. There was significant variation among strains for the percentage of eggs oviposited on each medium, ranging from 70 +/- 4% (SE) preference for plain food to no significant preference. Reciprocal hybrid, backcross, and F2 generations derived from two extreme parent strains revealed significant additive and nonadditive genetic variation but no evidence of maternal, paternal, or sex-chromosome effects.

Animals↗
PubMed1999

Early and late reversal of rocuronium and vecuronium with neostigmine in adults and children.

UNLABELLED: We investigated the influence of the timing of neostigmine administration on recovery from rocuronium or vecuronium neuromuscular blockade. Eighty adults and 80 children were randomized to receive 0.45 mg/kg rocuronium or 0.075 mg/kg vecuronium during propofol/fentanyl/N2O anesthesia. Neuromuscular blockade was monitored by train-of-four (TOF) stimulation and adductor pollicis electromyography. Further randomization was made to control (no neostigmine) or reversal with 0.07 mg/kg neostigmine/0.01 mg/kg glycopyrrolate given 5 min after relaxant, or first twitch (T1) recovery of 1%, 10%, or 25%. Another eight adults and eight children received 1.5 mg/kg succinylcholine. At each age, spontaneous recovery of T1 and TOF was similar after rocuronium and vecuronium administration but was more rapid in children (P < 0.05). Spontaneous recovery to TOF0.7 after rocuronium and vecuronium administration in adults was 45.7 +/- 11.5 min and 52.5 +/- 15.6 min; in children, it was 28.8 +/- 7.8 min and 34.6 +/- 9.0 min. Neostigmine accelerated recovery in all reversal groups (P < 0.05) by approximately 40%, but the times from relaxant administration to TOF0.7 were similar and independent of the timing of neostigmine administration. Recovery to T1 90% after succinylcholine was similar in adults (9.4 +/- 5.0 min) and children (8.4 +/- 1.1 min) and was shorter than recovery to TOF0.7 in any reversal group after rocuronium or vecuronium administration. Recovery from rocuronium and vecuronium blockade after neostigmine administration was more rapid in children than in adults. Return of neuromuscular function after reversal was not influenced by the timing of neostigmine administration. These results suggest that reversal of intense rocuronium or vecuronium neuromuscular blockade need not be delayed until return of appreciable neuromuscular function has been demonstrated. IMPLICATIONS: These results suggest that reversal of intense rocuronium or vecuronium neuromuscular blockade need not be delayed until return of appreciable neuromuscular function has been demonstrated. Although spontaneous and neostigmine-assisted recovery is more rapid in children than in adults, in neither is return of function as rapid as after succinylcholine administration.

Adult↗
PubMed1998

Correlation of tumor size and axillary lymph node involvement with prognosis in patients with T1 breast carcinoma.

BACKGROUND: The prognosis of patients with T1 breast carcinoma remains controversial. Some studies have shown a low risk of lymph node metastasis and distant failure whereas others have not, possibly due to differences in the definition of tumor size. In this study, the authors assessed the relation between macroscopic tumor size, microscopic invasive tumor size, axillary lymph node involvement, and prognosis in a group of patients with clinically lymph node negative disease. METHODS: Between 1968 and 1986, 1865 women with American Joint Committee on Cancer clinical Stage I or II infiltrating carcinoma of the breast were treated at the Joint Center for Radiation Therapy with conservative surgery and radiation therapy. The study population was limited to 118 patients with clinically negative axillary lymph nodes for whom the macroscopic pathologic tumor size was identified unambiguously as being < or = 2.0 cm, who underwent an axillary lymph node dissection with at least 6 lymph nodes sampled, and for whom the microscopic size of the invasive component could be determined. The median follow-up time for surviving patients was 134 months (range, 90-208 months). No patients with pathologically negative axillary lymph nodes received systemic therapy. RESULTS: Macroscopic and microscopic tumor sizes differed by > 5 mm in 17 patients (14%), by 3-5 mm in 24 patients (20%), and by < or = 2 mm in 77 patients (65%). The macroscopic tumor size was smaller than the microscopic size in 37 patients (31%), larger in 55 patients (47%), and equal in 26 patients (22%). Pathologic axillary lymph node involvement was present in 21% of all patients. The risk of lymph node involvement was not significantly different for those patients with tumors < or = 1 cm compared with patients with tumors > or = 1.1 cm, regardless of whether tumor size was measured by macroscopic or microscopic examination. The 10-year actuarial rate of freedom from distant recurrence (FFDR) was 91% for lymph node negative patients with macroscopic tumors measuring < or = 1.0 cm compared with 77% for patients with macroscopic tumors measuring > or = 1.1 cm (P = 0.07). When measured microscopically, the rates were 96% and 72%, respectively (P = 0.001). CONCLUSIONS: There often is a discrepancy between microscopic tumor size and macroscopic tumor size. T1 tumors have a substantial risk of axillary lymph node metastasis whether measured macroscopically or microscopically. Among those patients with pathologic lymph node negative tumors who are not treated with systemic adjuvant therapy, microscopic invasive tumor size is a better predictor of 10-year FFDR than macroscopic tumor size. There is a substantial risk of distant failure for patients with tumors whose invasive component microscopically measure > or = 1.1 cm, whereas the prognosis for patients with tumors that microscopically measured < or = 1 cm is excellent. These results suggest that the microscopic size of the invasive component of breast carcinomas < or = 2.0 cm routinely should be reported.

Adult↗
PubMed1998

Risk to patients from radiation associated with radiofrequency ablation for supraventricular tachycardia.

BACKGROUND: Radiofrequency ablation may be associated with prolonged fluoroscopy times. Previous studies have calculated radiation risks by measuring the radiation dose at a limited number (6) of body sites. This is an inherently inaccurate measure. Our study aimed to quantify more precisely patient-related radiation risks associated with radiofrequency ablation for supraventricular tachycardia. METHODS AND RESULTS: Nine female patients having radiofrequency ablation for supraventricular tachycardia were studied. The radiation dose was determined at 41 body sites in each patient with the use of thermoluminescent dosimeters and was correlated with that measured simultaneously with a Diamentor dose-area product meter. The estimated mean organ doses (mGy) per 60 minutes of fluoroscopy were: lungs 30.8; bone marrow 4.3; left breast 5.1; right breast 3. 5; and thyroid 2.4. From the average organ doses, the estimated mean total lifetime excess risk of a fatal malignancy was 294 per million cases (0.03%) per 60 minutes of fluoroscopy. The risk calculation from the Diamentor dose-area product and thermoluminescent dosimeters were similar, suggesting that radiation dose was measured accurately. The estimated risk of radiation-induced malignancy increased with increasing body mass index (P=0.03). CONCLUSIONS: Prolonged fluoroscopy during radiofrequency ablation may potentially cause a small increase in the lifetime risk of fatal malignancy, with lung malignancy being most likely. This risk is small only with the use of techniques and x-ray equipment optimized to keep radiation as low as possible. The risk is increased in obese patients.

Adult↗
PubMed1998

DNA cytometry and chromosome 9 aberrations by fluorescence in situ hybridization of irrigation specimens from bladder cancer patients.

OBJECTIVES: To determine the sensitivity and specificity of combining fluorescence in situ hybridization (FISH) measurement of chromosome 9 and DNA cytometry of bladder irrigation specimens in the detection of bladder cancer. METHODS: Bladder irrigation specimens were obtained from 37 normal control patients and 317 bladder cancer patients during cystoscopic examinations. Bladder cancer patients were sampled in the absence of observable tumor (256 specimens) and concurrently with tumor (204 specimens). Chromosome 9 copy number was determined on a cellular basis by FISH, and cellular DNA content was determined by Feulgen DNA staining and image cytometry. RESULTS: Sensitivity of chromosome 9 FISH was 42% for all tumors and was not correlated to transitional cell carcinoma tumor grade, while the sensitivity of DNA cytometry was 55% and improved with increasing grade from 38% for grade 1 to 90% for grade 3 tumors. The results of FISH and DNA cytometry were combined, resulting in specificity of 92% and sensitivity of 69% for grade 1, 76% for grade 2, and 97% for grade 3 tumors. CONCLUSIONS: The lack of increase with grade in the percentage of positive specimens by FISH supports the hypothesis that chromosome 9 aberrations are critical events in bladder tumorigenesis for many patients. These data demonstrate the presence of cells in irrigation specimens with specific genomic lesions of chromosome 9 and DNA content. Combining FISH on chromosome 9 and DNA cytometry provides an increase in sensitivity to transitional cell carcinoma over either test alone.

Carcinoma, Transitional Cell↗
PubMed1998

The incidence of large venous emboli during total knee arthroplasty without pneumatic tourniquet use.

UNLABELLED: Echogenic venous emboli accompany tourniquet deflation during total knee arthroplasty. Two types of echogenic emboli appear in the central circulation: small venous emboli (miliary emboli) and large venous emboli (masses of echogenic material superimposed on miliary emboli). Presumably, medullary cavity trespass releases small and large echogenic emboli. However, patients undergoing lower extremity procedures with a tourniquet have large echogenic emboli regardless of medullary cavity invasion. Avoiding tourniquet inflation may decrease the release of large venous emboli. Thirteen patients undergoing total knee arthroplasty without pneumatic tourniquet received intramedullary guides and 11 patients received tibial extramedullary guides. Recordings of hemodynamic variables, mixed venous oximetry, end-tidal CO2, and echocardiographic images were made after the induction of anesthesia and for 15 min after femoral prosthesis cementing. Mean arterial pressure did not change during the study, and mean pulmonary arterial pressure increased minimally. Large venous emboli appeared in eight patients, small venous emboli appeared in 12 patients, and no emboli appeared in four patients. Compared with previous investigations of large venous emboli during total knee arthroplasty with a pneumatic tourniquet, multiple logistic regression analysis discloses a 5.33-fold greater risk of large venous embolism accompanied the use of a tourniquet during total knee arthroplasty. IMPLICATIONS: One third of knee replacements performed without a tourniquet demonstrated large emboli. Reducing marrow cavity invasion did not decrease the release of large emboli. Compared with knee replacement without tourniquet, tourniquet use places patients at a 5.33-fold greater risk of having a large emboli.

Adult↗
PubMed1998

Automated atlas integration and interactive three-dimensional visualization tools for planning and guidance in functional neurosurgery.

Many critical functionally distinct subcortical structures are not distinguishable on anatomical magnetic resonance imaging (MRI) scans. In order to provide the neurosurgeon with this missing information, a deformable volumetric atlas of the basal ganglia and thalamus has been created from the Schaltenbrand and Wahren atlas of cryogenic slices. The volumetric atlas can be automatically deformed to an individual patient's MRI. To facilitate the clinical use of the atlas, a visualization platform has been developed for preoperative and intraoperative use which permits manipulation of the merged atlas and MRI data sets in two- and three-dimensional views. The platform includes graphical tools which allow the visualization of projections of a leukotome and other surgical tools with respect to the atlas data, as well as preregistered images from any other imaging modality. In addition, a graphical interface has been designed to create custom virtual lesions using computer models of neurosurgical tools for intraoperative planning. To date this system has been employed as an adjunct to over 30 functional neurosurgical cases including surgery for movement disorders.

Algorithms↗
PubMed1998

Evaluation of radiation dose and risk to the patient from coronary angiography.

BACKGROUND: Coronary angiography is a commonly performed diagnostic procedure with life saving benefits for the patient. However, because of its potential to deliver a high radiation dose, caution is warranted. AIM: The purpose of this study was to determine the effective dose to an average patient from coronary angiography, to estimate the associated radiation risk in terms of fatal malignancy, and to examine ways effective dose may be reduced. METHOD: The dose-area product data from 210 examinations was used to determine the effective dose to the average patient by means of a commercially available software programme. Subsequently, the effective dose was used to estimate radiation risk based on the population averaged probability coefficients given in ICRP 60 and contrasted against age-related risk coefficients from the NRPB. The components of effective dose and radiation risk were examined to identify the organs most at risk. RESULTS: The average effective dose was found to be 3.4 +/- 1.3 mSv. The risk of fatal malignancy was estimated as 170 per million cases, or around one in 6000. The average lung dose was 14.7 mSv, with the risk of fatal lung cancer estimated as 125 per million cases or one in 8000. CONCLUSIONS: The average effective dose in this study was less than half that of most other studies. The lung was identified as the critical organ and the estimated risk of fatal cancer amounted to an increase of 0.017% above the normal incidence for the general population. The study affirmed that using a reduced cine frame rate, low dose pulsed fluoroscopy, added copper filtration and a conscious effort to reduce screening time can significantly reduce patient dose.

Adult↗
PubMed1998

Contribution of rpoB mutations to development of rifamycin cross-resistance in Mycobacterium tuberculosis.

The contributions of 23 insertion, deletion, or missense mutations within an 81-bp fragment of rpoB, the gene encoding the beta-subunit of the DNA-dependent RNA polymerase of Mycobacterium tuberculosis, to the development of resistance to rifamycins (rifampin, rifabutin, rifapentine, and KRM-1648) in 29 rifampin-resistant clinical isolates were defined. Specific mutant rpoB alleles led to the development of cross-resistance to all rifamycins tested, while a subset of mutations were associated with resistance to rifampin and rifapentine but not to KRM-1648 or rifabutin. To further study the impact of specific rpoB mutant alleles on the development of rifamycin resistance, mutations were incorporated into the rpoB gene of M. tuberculosis H37Rv, contained on a mycobacterial shuttle plasmid, by in vitro mutagenesis. Recombinant M. tuberculosis clones containing plasmids with specific mutations in either codon 531 or 526 of rpoB exhibited high-level resistance to all rifamycins tested, whereas clones containing a plasmid with a mutation in codon 516 exhibited high-level resistance to rifampin and rifapentine but were susceptible to both rifabutin and KRM-1648. These results provided additional proof of the association of specific rpoB mutations with the development of rifamycin resistance and corroborate previous reports of the usefulness of rpoB genotyping for predicting rifamycin-resistant phenotypes.

Anti-Bacterial Agents↗