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Biomedical subjects

W L Carroll

Publications and source records attributed to W L Carroll.

48 records · Page 3Linked to original sources

Large-cell calcifying sertoli cell tumor of the testis. An ultrastructural, immunocytochemical, and biochemical study.

This report describes the ultrastructural and hormonal characteristics of the recently described large-cell calcifying Sertoli cell tumor of the testis, a rare subtype of pure Sertoli cell tumor. The ultrastructural findings showed similarity to normal Sertoli cells, pure Sertoli cell tumors, Sertoli cells in azoospermic human testes, and the Sertoli cell component of Sertoli-Leydig cell tumors. Ultrastructure indicated features common to steroid-producing cells. Testosterone and estradiol were demonstrated in the tumor by immunocytochemical and biochemical methods.

Basement Membrane↗

Treatment of occult bacteremia: a prospective randomized clinical trial.

Antibiotic therapy for children without foci of infection and at risk for bacteremia is controversial. A prospective randomized clinical trial was conducted using expectant antibiotic therapy in children at risk for bacteremia. A total of 96 children (aged 6 to 24 months) with temperature of more than 40 degrees C, no identifiable source of infection, and a leukocyte count greater than or equal to 15,000/microL and/or sedimentation rate greater than or equal to 30 were enrolled. The following tests were performed on all children: blood culture, chest roentgenogram, urinalysis, and urine culture. A lumbar puncture was performed if a child was 12 months or less. Patients were randomized to receive either no antibiotic therapy or Bicillin C-R, 50,000 U/kg intramuscularly, followed by penicillin V, 100 mg/kg/d, orally four times a day for three days. Patients were examined at 24 and 72 hours. Fifty patients were treated expectantly and 46 received no antimicrobial therapy. Ten of the 96 patients were bacteremic (nine had Streptococcus pneumoniae, one had Haemophilus influenzae). Four of the five children treated for bacteremia showed improvement at the first follow-up visit (afebrile and no obvious focus of infection). The five untreated patients showed no improvement; four patients developed focal infections (two had meningitis, two had otitis media) (P less than or equal to .05, Fisher exact test). No complications of expectant therapy were detected. Thus, expectant antibiotic therapy for children who have no obvious source of infection and who meet these criteria associated with occult bacteremia is warranted.

Child, Preschool↗

Transcutaneous electrical stimulation as an adjunct in the management of myofascial pain-dysfunction syndrome.

Twenty-one patients, 14 women and seven men, presenting with symptoms of the MPD syndrome, were treated with a regimen based on a neuromuscular theory of occlusion involving TES. Evaluation of treatment results shows 95% success immediately after therapy and an 86% success 1 year after therapy. No effort was made to establish a personality profile on the patients nor to incorporate active psychotherapy in treatment.

Adolescent↗

Spectrum of Salmonella-associated arthritis.

Arthritis is an uncommon extraintestinal manifestation of Salmonella infection. Three patients with Salmonella-associated arthritis with varying manifestations were seen at Children's Hospital Medical Center in an 11-month period: (1) a 12-year-old girl developed suppurative arthritis due to Salmonella typhimurium that required surgical drainage and prolonged parenteral antibiotic therapy; (2) a 12-year-old girl had migratory polyarthritis following gastrointestinal infection with S typhimurium; the acute synovitis subsided after a six-month period following anti-inflammatory medications; (3) a 14-year-old girl developed conjunctivitis, urethritis, and polyarthritis (Reiter's syndrome) in association with Salmonella gastroenteritis. These patients illustrate the distinct types of arthritis associated with Salmonella gastroenteritis. These patients illustrate that distinct types of arthritis associated with Salmonella, and the association of this organism with both suppurative joint disease and reactive arthritis is reemphasized.

Adolescent↗

A shuttle vector system for the investigation of immunoglobulin gene hypermutation: absence of enhanced mutability in intermediate B cell lines.

Somatic hypermutation focused to the rearranged V(D)J segment of the immunoglobulin (Ig) loci contributes substantially to antibody gene diversification. However, neither the precise B cell subset subject to hypermutation nor the molecular mechanism(s) involved is known. One model proposes that Ig segments may be uniquely susceptible to DNA nicking and subsequent error-prone repair during a specific B cell developmental stage. We describe an SV40-based shuttle vector system for testing such a model. Plasmids containing two distinct Ig segments juxtaposed to the supF marker gene have been passaged through cell lines representing intermediate stages of B cell development, rescued and screened for marker gene mutations. To date we have not demonstrated enhanced supF mutation in any cell line examined, irrespective of the adjacent Ig segment. Thus, these cell lines exhibit normal DNA repair mechanisms and no evidence of increased endonuclease activity on the Ig segments tested. The feasibility of this system will allow similar experiments using other Ig target sequences exposed to a broader range of B cells.

Antibody Diversity↗

Expression of the c-Myc protein in childhood medulloblastoma.

PURPOSE: The purpose of this study was to determine the incidence of c-Myc protein expression in medulloblastoma/primitive neuroectodermal tumor (MB/PNET) and to identify mechanisms in addition to c-myc gene amplification that lead to increased protein expression. METHODS: We analyzed c-myc gene copy number, mRNA level and protein expression in a panel of MB/PNET cell lines. C-Myc protein levels were assessed in tumor specimens and cell lines using immunohistochemical staining with a c-Myc-specific monoclonal antibody. RESULTS: Southern analysis confirmed c-myc gene amplification in the D425 MED cell line and re-arrangement of one allele in D283 MED, which was analyzed further and appeared to represent a small deletion 3' of exon 3. C-myc transcript levels were dramatically elevated in both lines. Using a c-myc probe, fluorescence in situ hybridization (FISH) showed c-myc present in 3 tandem copies at 8q24 in D283 MED and multiple copies as double minutes in D425 MED. Immunohistochemistry showed c-Myc protein expression in 9 of 10 tumors and all cell lines, regardless of gene amplification status or level of mRNA expression. CONCLUSIONS: c-Myc protein expression is common in MB/PNET tumor specimens and cell lines. Elevated protein levels are observed in the absence of amplification, suggesting that multiple mechanisms of c-myc dysregulation may be involved in MB/PNET. These studies support a role for c-Myc in the development of this common childhood tumor.

Child↗

Coexpression of genes involved in apoptosis in central nervous system neoplasms.

PURPOSE: Apoptosis plays a crucial role in normal development and mediates tumor response to chemotherapy. This study investigated the pattern of apoptotic gene expression in brain tumor tissue specimens and cell lines. MATERIALS AND METHODS: BCL2, BCLXL, BCLXS, and BAX transcripts were amplified using reverse transcriptase polymerase chain reaction in 7 high-grade gliomas (HGGs), 7 ependymomas, and 6 cell lines (2 glioblastomas, 3 medulloblastomas, and 1 supratentorial-primitive neuroectodermal tumor [PNET]). Immunohistochemical staining for BCL2, BCLX, BAX, and p53 was performed in 7 pediatric low-grade gliomas (LGGs) and 7 pediatric HGGs. RESULTS: Six of seven gliomas, all ependymomas, and all glioblastoma and medulloblastoma cell lines expressed BCLXL and BAX. BCL2 expression was only detected in the supratentorial PNET line PFSK. BCLXS was absent in all tumors. By immunohistochemistry, no glial tumors stained positively for BCL2. Similar BAX and BCLX protein expression was observed in LGG and HGG. Three of five glioblastomas showed significant p53 expression. CONCLUSIONS: Coexpression of proapoptotic and antiapoptotic genes in human brain tumors supports the hypothesis that the relative expression of competing genes determines apoptotic threshold.

Apoptosis↗