Biomedical subjects

D B Nguyen

Publications and source records attributed to D B Nguyen.

5 recordsLinked to original sources

PubMed2000

Denture esophageal impaction refractory to endoscopic removal in a psychiatric patient.

Impaction of dental prostheses is frequently encountered in psychiatric patients. These patients may present an especially challenging problem because the diagnosis may be delayed, resulting in increased morbidity and mortality. Delay in diagnosis in such patients has been attributed to their inability to give a reliable clinical history. In addition, radiolucent dentures cannot be easily detected by radiographic examination. The purpose of this report is to describe a psychiatric patient with an impacted radiopaque dental prosthesis that was refractory to endoscopic intervention. An esophagotomy was needed to successfully remove the foreign body.

Dental Prosthesis↗

PubMed2000

Complete breast absence revisited.

Congenital absence of the breast is a rare condition. The literature shows that there is much heterogeneity in its presentation as well as its inheritance. We described a mother and daughter with the condition and how the mother underwent breast reconstruction with use of bilateral transverse rectus abdominis myocutaneous flaps.

Abnormalities, Multiple↗

PubMed1990

Dose-response curves for Fricke-infused agarose gels as obtained by nuclear magnetic resonance.

The radiation-response characteristics of agarose gels prepared with Fricke dosemeter solution have been studied. The response mechanism is an increase in the NMR longitudinal relaxation rate of protons caused by ferric ions. It has been observed that: (i) oxygen saturation assures consistent and maximum sensitivity; (ii) agarose concentrations in the range 1.0-2.0% have no effect upon sensitivity; (iii) the initial G value is 150 Fe3+/100 eV for gels containing 0.5 mM Fe2+ ions; (iv) increasing NMR frequencies only causes a moderate increase in sensitivity; (v) the gel dosemeters are dose rate independent in the range 4.7-24.2 Gy min-1; (vi) sensitivity is pH dependent, being zero at pH 7; (vii) freshly prepared gels are slightly more sensitive than those more than 24 h old; and (ix) the diffusion coefficient for ferric ions in a 1.0% agarose gel containing 0.0125 M H2SO4 is 1.83 x 10(-2) cm2 h-1, and this will require consideration for the NMR imaging of dose distributions.

Dose-Response Relationship, Radiation↗

PubMedDate not supplied

Appendectomy in the pre- and postlaparoscopic eras.

The role of laparoscopic appendectomy remains controversial since many authors have suggested that overall morbidity is primarily a function of the degree of appendicitis rather than the operative approach. We have reviewed our appendectomy experience to determine the advantages and/or disadvantages of the laparoscopic technique in cases of acute appendicitis, and furthermore to ascertain whether the extent of disease should affect the surgical approach used. Data were accumulated for all 1158 patients who underwent appendectomy at a single institution during the following three time periods that span the pre- and postlaparoscopic eras: period I (1987 to 1990), period II (1991 to 1993), and period III (1994 to 1997). Cases were categorized with regard to pathologic findings and operative approach (i.e., open or laparoscopic appendectomy). The percentage of appendectomies performed laparoscopically increased with time (0%, 27%, and 79% for periods I, II, and III, respectively). Overall, the total operating room time was slightly shorter for laparoscopic compared to open appendectomy (99 vs. 102 minutes; P<0.05). Operating room times for open appendectomy remained unchanged, but the times for laparoscopic appendectomy decreased from period II to period III (119 to 94 minutes; P<0.001). In cases of gangrenous/perforated appendicitis, the times for laparoscopic appendectomy were significantly shorter than those for open appendectomy (98/115 vs. 120/125 minutes; P<0.001 for both). Overall, the hospital stay was shorter for patients undergoing laparoscopic appendectomy (1.63 vs. 4.21 days; P<0.001), and the difference was maintained in all three time periods. The differences in length of hospital stay for lap-aroscopic vs. open appendectomy were most dramatic in gangrenous/perforated cases (1.8/3.0 vs. 4.0/9.0 days; P<0.001), whereas there was only a slight difference in cases of simple appendicitis, for example, 1.6 vs. 2.1 days (laparoscopic vs. open appendectomy, period III). There was a significant decrease in the percentage of perforated cases in which surgical treatment had been delayed (>8 hours) (21%, 5%, and 5%) over the three time periods, but the rate of "negative" appendectomies was similar (10%, 8%, and 8%). The complication rates following laparoscopic and open appendectomies during period II were 5.4% and 7.5%, respectively (P>0.05). Laparoscopic appendectomy results in a marked decrease in the length of hospital stay and similar postoperative morbidity compared to open appendectomy. In cases of gangrenous or perforated appendicitis, laparoscopic appendectomy appears to be especially worthwhile in regard to both operating room time and hospital stay.

Acute Disease↗

PubMedDate not supplied

Interval appendectomy in the laparoscopic era.

In the acute setting, patients with periappendiceal masses generally improve with broad-spectrum antibiotics with or without percutaneous catheter drainage, but whether or not to perform an interval appendectomy remains controversial. We have analyzed our experience over the past decade, comparing results from interval laparoscopic appendectomy (ILA) and interval open appendectomy (IOA). Medical records were reviewed for 56 patients who initially presented with the diagnosis of periappendiceal mass or abscess and who subsequently underwent interval appendectomy. Data were accumulated for both the initial hospitalization and interval appendectomy. Comparisons were made between period 1 (1987 to 1993) and period 2 (1994 to 1997). Follow-up data were obtained via telephone conversations with the patients. Patient characteristics with regard to age, sex, and comorbidities did not differ between the ILA and IOA groups. The number of patients undergoing CAT scan increased from 33% to 55%, whereas the initial hospital stay decreased from 7. 42 to 4.61 days (P<0.001). The percentage of interval appendectomies performed by the laparoscopic method increased from 30% to 85%. The total operating room time did not differ (95 vs. 103 minutes), but the hospital stay was much shorter in the ILA group (0.55 vs. 3.07 days, P<0.001). There were no instances of intra-abdominal or wound infections in either group. In the later time period the mean hospital stay decreased to 0.38 days, with 59% of the operations performed on an outpatient basis. Following ILA, narcotic pain medication was used for an average of 1.3 days and the reported "time to return to full activities" was 2.5 days. ILA is a simple and safe procedure that can usually be performed on an outpatient basis. Given the minimal morbidity of the procedure, we believe that ILA should be considered for most patients who initially present with periappendiceal masses.

Appendectomy↗