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Biomedical subjects

K R Lee

Publications and source records attributed to K R Lee.

At least 19 recordsLinked to original sources
PubMed1995

Carcinosarcoma (malignant mixed müllerian tumor) of the uterus with a rhabdoid tumor component. An immunohistochemical, ultrastructural, and immunoelectron microscopic case study.

A case of uterine carcinosarcoma (malignant mixed müllerian tumor) of the uterus containing a rhabdoid tumor element is described. In addition to a malignant glandular component and anaplastic sarcomatous areas, this tumor had multiple foci with histologic and ultrastructural features of malignant rhabdoid tumor. Vimentin positivity by immunohistochemistry was confirmed by immunoelectron microscopy. Although three malignant rhabdoid tumors of the uterus have been previously described, in addition to rhabdoid differentiation in an endometrial stromal sarcoma, to our knowledge this is the first report of rhabdoid tumor differentiation occurring within a uterine carcinosarcoma.

Aged↗
PubMed1995

Gonococcal abscess of the obturator internal muscle: use of new diagnostic tools may eliminate the need for surgical intervention.

Obturator internal muscle (OIM) abscess or pyomyositis, a poorly recognized intrapelvic infection, is characterized by limping, pain in the hip with limited movement, and the sciatic type of radiating leg pain. With the use of advanced diagnostic tools such as computed tomography (CT), magnetic resonance imaging, and radionuclide scans, several cases of OIM abscess have been diagnosed; these cases have recently been reported in the English-language literature. Staphylococcus aureus is the predominant organism isolated from OIM abscesses. Gonococcal abscess involving the OIM has not been reported. We describe a case of gonococcal OIM abscess in an adolescent female whose condition was successfully diagnosed and managed with the use of CT-guided needle aspiration and antibiotic therapy. We review the English-language literature regarding the use of newly developed tools in the diagnosis of OIM abscess.

Abscess↗
PubMed1995

Prophylactic antibiotic use in pediatric cardiovascular surgery: a survey of current practice.

There is little information on prophylactic antibiotic practice in pediatric cardiovascular surgery. A consensus prophylactic antibiotic practice, if identified, might serve as a standard to which alternative prophylactic antibiotic practice could be compared. We surveyed North American academic centers with pediatric cardiovascular surgery programs regarding their standard antimicrobial prophylaxis regimens, duration of prophylaxis and modification of prophylaxis for lesion, patient age or medical device considerations. Forty-three (81%) of 53 centers responded; not all responses were complete. Monotherapy was used by 39 (91%) of 43; 38 (97%) of 39 used a 1st or 2nd generation cephalosporin (cefazolin 24, cefamandole 8, cefuroxime 4, cephapirin 1, unspecified 1) and 1 of 39 used vancomycin. Only 4 (9%) of 43 used 2 antibiotics. Prophylactic antibiotics were started pre- or intraoperatively by 41 of 43 centers and discontinued within 2 days by 25 of 37. Prophylactic antibiotics were often continued while thoracostomy tubes (29 of 43), mediastinal tubes (31 of 43) or transthoracic vascular catheters (22 of 43) were in place, but usually not for endotracheal tubes (6 of 43), arterial (9 of 43) or percutaneous central venous (13 of 43) catheters or temporary pacing wires (6 of 43). Our survey indicates that the consensus prophylactic antibiotic regimen for pediatric cardiovascular surgery is monotherapy with a first or second generation cephalosporin, used for < or = 2 days or until transthoracic medical devices are removed.

Anti-Bacterial Agents↗
PubMed1995

Abdominal wall hernias: review of herniography and correlation with cross-sectional imaging.

Herniography is an accurate means of identifying groin hernias when the clinical diagnosis is uncertain. Its role in evaluation of other types of ventral hernias is less clear; however, with minor modifications in technique, herniography is also useful in these cases. This article reviews the technique of herniography, normal variations in anatomy, and interpretation of herniograms of the groin and anterior abdominal wall on the basis of 72 patients studied over 3 1/2 years. Herniography is also compared with cross-sectional imaging techniques. Inguinal and femoral hernias are best shown and classified with herniography. Ventral hernias are well demonstrated by both herniography and cross-sectional imaging; however, herniation of only fat and supine imaging may lead to misdiagnosis with computed tomography or ultrasound. Spigelian hernias are probably best depicted with cross-sectional imaging. Diagnostic pitfalls of herniography are reviewed, including the need for obtaining postexercise radiographs, oblique radiographs, and tangential radiographs.

Female↗
PubMed1995

Intracerebral infusion of thrombin as a cause of brain edema.

Purified thrombin from an exogenous source is a hemostatic agent commonly used in neurosurgical procedures. The toxicity of thrombin in the brain, however, has not been examined. This study was performed to assess the effect of thrombin on brain parenchyma, using the formation of brain edema as an indicator of injury. Ten microliters of test solution was infused stereotactically into the right basal ganglia of rats. The animals were sacrificed 24 hours later, and the extent of brain edema and ion content were measured. Concentrations of human thrombin as low as 1 U/microliter resulted in a significant increase in brain water content. Rats receiving 10 U/microliters had a mortality rate of 33% compared to no mortality in the groups receiving smaller doses. Thrombin-induced brain edema was inhibited by a specific and potent thrombin inhibitor, hirudin. A medical grade of bovine thrombin commonly used in surgery also caused brain edema when injected at a concentration of 2 U/microliters. Edema formation was prevented by another highly specific thrombin inhibitor, N alpha-(2-Naphthalenesulfonylglycyl)-4-DL-phenylalaninepiperidid e (alpha-NAPAP). Thrombin-induced brain edema was accompanied by increases in brain sodium and chloride contents and a decrease in brain potassium content. Changes in brain ions were inhibited by both hirudin and alpha-NAPAP, corresponding to the inhibition of brain water accumulation. This study shows that thrombin causes brain edema when infused into the brain at concentrations as low as 1 U/microliter, an amount within the range of concentrations used for topical hemostasis in neurosurgery.

Animals↗
PubMed1994

Functional association of essential splicing factor(s) with PRP19 in a protein complex.

We have previously shown that the yeast PRP19 protein is a spliceosomal component, but is not tightly associated with small nuclear RNAs. It appears to associate with the spliceosome concomitant with or just after dissociation of the U4 small nuclear RNA during spliceosome assembly. We have found that PRP19 is associated with a protein complex in the splicing extract and that at least one of the associated components is essential for splicing. Taking advantage of the epitope tagging technique, we have isolated the PRP19-associated complex by affinity chromatography. The isolated complex is functional for complementation for the heat-inactivated prp19 mutant extract, and consists of at least seven polypeptides in addition to PRP19. At least three of these can interact directly with the PRP19 protein. We also show that the PRP19 protein itself is in an oligomeric form, which might be a prerequisite for its interaction with these proteins.

Base Sequence↗
PubMed1994

Traditional and nontraditional histopathologic predictors of recurrence in uterine endometrioid adenocarcinoma.

Ninety-three consecutive operative cases of myometrial invasive endometrioid adenocarcinoma of the uterus without evidence of extrauterine spread at surgery were reviewed to determine whether any histopathologic features other than those traditionally reported might predict recurrence. Recurrence was associated with traditionally analyzed features of deep myometrial invasion, high FIGO grade, vascular space invasion, and cervical stromal invasion as well as patient age. In addition, a diffuse pattern of myometrial invasion was associated with an increased risk for recurrence. Contrary to results from previous studies, no increased risk was seen with high nuclear grade or the presence of perivascular lymphocytic infiltrates. When adjusted for traditional parameters, perivascular lymphocytes and a tumor-host inflammatory response were associated with prolonged time to recurrence. A desmoplastic host response or residual adenomyosis were unrelated to recurrence.

Abdominal Neoplasms↗
PubMed1994

MRI of Joubert's syndrome.

OBJECTIVE: To report five cases of the rare Joubert's syndrome. SUBJECTS: All five cases were studied by 1.0-Tesla MRI. All the patients showed typical clinical manifestations of Joubert's syndrome including neonatal respiratory abnormalities, developmental delay, ataxia, retinal atrophy and nystagmus. RESULTS: The T1WI of MRI showed characteristic MRI features of Joubert's syndrome including dilatation of the fourth ventricle with some appearing bat-wing shaped, elongation and stretching of the superior cerebellar peduncles, dysphasia of the vermis, widening of the foramen of Magendie and the posterior cistern. One case was associated with encephalomeningocele. CONCLUSIONS: MRI can provide characteristic findings of Joubert's syndrome and confirm the clinical diagnosis.

Brain↗
PubMed1994

Drug use evaluation of antibiotics in a pediatric teaching hospital.

OBJECTIVE: To determine the incidence and type of antibiotic use variances at our institution. DESIGN: Inpatient bacterial culture and susceptibility results were reviewed for 1 week per month. Medication administration records were evaluated to determine whether antibiotic selection was appropriate, given the susceptibility of the organism. Process indicators included use of the least costly antibiotic, as well as appropriate dose, interval, and route of administration. The complete medical record was reviewed for all patients if management did not appear to meet criteria. SETTING: A 225-bed, tertiary-care children's teaching hospital. RESULTS: Thirty-five (8.2%) of 428 patients reviewed over 12 months had a total of 49 variances: failure to treat (3), treatment of contaminant/colonizer (2), use of more costly agent (10), failure to revise therapy (8), inappropriate route (2), inappropriate empiric antibiotic (4), incorrect dose (3), unnecessary multiple antibiotics (6), inappropriate drug (8), and prolonged prophylaxis (3). CONCLUSIONS: Thirty-five patients with 10 types of variances were identified during the study. Follow-up monitoring will assess the impact of educational efforts on the incidence of variances. Specific problem antibiotics have been identified for further audits.

Anti-Bacterial Agents↗
PubMed1994

Staphylococcus epidermidis meningitis and an intraspinal abscess associated with a midthoracic dermal sinus tract.

Congenital neuroectodermal defects are associated with meningitis that is unresponsive to conventional antibiotic therapy, recurrent bacterial meningitis, or meningitis due to an organism that is not usually the cause of this disease. Midthoracic dermoid and epidermoid cysts occur rarely and are easily overlooked. We report the case of a 13-month-old boy with meningitis that was unresponsive to antimicrobial therapy. We subsequently identified an intraspinal abscess, an infection due to Staphylococcus epidermidis, and a midthoracic dermoid cyst. We emphasize the need for clinicians to have a high index of suspicion and to make a careful physical examination when antibiotic treatment fails in patients with meningitis. We also provide a detailed anatomy of a midthoracic dermoid cyst and illustrate the usefulness of magnetic resonance imaging in preoperative diagnosis of congenital neuroectodermal defects.

Abscess↗
PubMed1994

Ultrasound detection of cerebral emboli in patients with prosthetic heart valves.

This study was undertaken in 64 patients, 50 with mechanical and 14 with porcine prosthetic valves, to evaluate the incidence of intracranial emboli and their distribution in the basal cerebral arteries. The patients were studied using transcranial Doppler (EME TC2-64B, Uberlingen, Germany), with a monitoring time of two minutes over each of the internal carotid arteries, middle and anterior cerebral arteries, vertebral arteries and the basilar artery. Sixty-three of the 64 patients were stabilized on warfarin at the time of the study. The incidence of emboli signals was significantly higher in patients with mechanical compared to porcine cardiac valves (88% versus 14%, p < 0.01). The number of emboli signals was significantly higher in the anterior compared with the posterior circulation, with a median of eight signals in the internal carotid arteries (95% confidence interval 5-15), 2.5 in the vertebral arteries (95% confidence interval 1-5.5)(p < 0.03). It was also significantly higher in those patients who had undergone double (aortic and mitral) as opposed to those who had undergone single aortic valve replacement: 18 versus two signals per minute (confidence intervals 5-30.5 versus 0.5-3.5) (p < 0.01). It is concluded that subclinical emboli signals are readily detectable using transcranial Doppler and are common in patients with prosthetic heart valves. Their number depends on both the type and the number of the prosthesis, while their distribution in the basal cerebral arteries is consistent with their cardiac source.

Adult↗
PubMed1993

Yeast precursor mRNA processing protein PRP19 associates with the spliceosome concomitant with or just after dissociation of U4 small nuclear RNA.

During assembly of the spliceosome, the U4 small nuclear RNA (snRNA) interacts with the spliceosome as a preformed U4/U6-U5 triple small nuclear ribonucleoprotein (snRNP) complex. Subsequently, U4 becomes loosely associated with the spliceosome, whereas U5 and U6 remain tightly associated, suggesting unwinding of the U4/U6 duplex. We show that this step of the assembly process can be blocked by limiting the ATP concentration in the splicing reaction. We also show that the yeast precursor mRNA processing protein PRP19 becomes associated with the spliceosome during this transition. Thus, PRP19 may function in this step of spliceosome assembly.

Adenosine Triphosphate↗
PubMed1993

Myelography, CT and MRI in leukaemic infiltration of the lumbar theca.

A 25-year-old woman with acute lymphoblastic leukaemia, while in remission, developed paraparesis, with faecal and urinary incontinence. CT demonstrated increased density of the lumbar theca and enlargement of the nerve roots. Myelography showed complete obstruction below the L3 level. MRI showed increased signal intensity in the lumbar sac on T1 weighting, and the cauda equina enhanced with gadolinium-DTPA. Lymphoblasts were seen in the lumbar spinal fluid. After chemotherapy, these abnormalities resolved, as did the paraparesis and incontinence.

Adult↗
PubMed1993

Challenge to the concept that UHMWPE acetabular components oxidize in vivo.

Severe wear of the ultra-high molecular weight polyethylene (UHMWPE) components of total joint replacements limits their long-term success. In previous studies, the infrared spectra obtained on retrieved UHMWPE components were interpreted as evidence that the UHMWPE oxidizes in vivo. In direct contrast, infrared spectroscopy of the retrieved UHMWPE acetabular components examined in this study demonstrated adsorbed esterified fatty acids, readily extractable by hexane, and no substantial evidence of in vivo oxidation. This emphasizes that special care must be taken when using infrared spectroscopy to assess retrieved components.

Adult↗
PubMed1993

The yeast PRP19 protein is not tightly associated with small nuclear RNAs, but appears to associate with the spliceosome after binding of U2 to the pre-mRNA and prior to formation of the functional spliceosome.

We have previously shown that the yeast PRP19 protein is associated with the spliceosome during the splicing reaction by immunoprecipitation studies with anti-PRP19 antibody. We have extended such studies by using extracts depleted of specific splicing factors to investigate the step of the spliceosome assembly process that PRP19 is involved in. PRP19 was not associated with the splicing complexes formed in U2- or U6-depleted extracts but was associated with the splicing complex formed in heat-inactivated prp2 extracts. This finding indicates that PRP19 becomes associated with the splicing complexes after or concomitant with binding of the U6 small nuclear ribonucleoprotein particle (snRNP) to the precursor RNA and before formation of the functional spliceosome. We further analyzed whether PRP19 is an integral component of snRNPs. We have constructed a strain in which an epitope of nine amino acid residues recognized by a well-characterized monoclonal antibody, 12CA5, is linked to the carboxyl terminus of the wild-type PRP19 protein. Immunoprecipitation of the splicing extracts with anti-PRP19 antibody or precipitation of the extracts prepared from the epitope-tagged strain with the 12CA5 antibody did not precipitate significant amounts of snRNAs. Addition of micrococcal nuclease-treated extracts to the PRP19-depleted extract restored its splicing activity. These results indicate that PRP19 is not tightly associated with any of the snRNAs required for the splicing reaction. No non-snRNP protein factor has been demonstrated to participate in either step of the spliceosome assembly pathway that PRP19 might be involved in. Thus, PRP19 represents a novel splicing factor.

Antibodies, Monoclonal↗