Biomedical subjects

J M Walton

Publications and source records attributed to J M Walton.

28 records · Page 2Linked to original sources

PubMed1994

Use of human dura in pediatric chest wall reconstruction after tumor resection.

The most difficult aspect of the surgical treatment of chest wall tumors is reconstruction of the large residual defect. Materials that have been used include Marlex, Goretex, Vicryl, bone, metal, and fascia. The authors' successful experience with dehydrated human dura (Tutoplast) for moderate-size defects is described. A large Askin's tumor in a 13-year-old boy required resection of the right posterior aspect of the 9th to 11th ribs and the transverse process of T-10, the 12- x 12-cm thoracic defect was closed with dura. Partial soft-tissue coverage was obtained with the latissimus dorsi muscle. Although a scoliosis secondary to paraspinal muscle resection has developed, the chest wall is stable, without evidence of a flail chest, at 18 months of follow-up. A 6-year-old girl underwent left anterior chest wall resection of three ribs for an epithelioid sarcoma. Human dura and a myocutaneous flap were used for reconstruction, with good functional and cosmetic results at 16 months of follow-up. Dura is simple to use, has low antigenicity, and in experimental studies appears to be incorporated into the tissues, acting as a collagen matrix. For moderate-size chest wall defects, it appears to be an excellent alternative to synthetic prosthesis.

Adolescent↗

PubMed1994

Gastrointestinal mucormycosis causing an acute abdomen in the immunocompromised pediatric patient--three cases.

Mucormycosis is an infection caused by a ubiquitous fungus in immunocompromised individuals. Typically, it invades blood vessels, producing thrombosis and tissue infarction. This infection spans all pediatric age groups and can lead to hollow viscus perforation and bowel obstruction. A 30-month old male with large cell anaplastic lymphoma had a bowel obstruction. During emergency laparotomy, an ileoileal intussusception was identified, which required resection and anastomosis. In the pathological specimen, fungi of the Mucorales order were found to be associated with tissue necrosis. On the eighth day of life, a premature infant had abdominal distension secondary to bowel perforation. Partial gastric resection and multiple intestinal stomas were performed. Death occurred soon after, secondary to multiorgan failure. The autopsy and surgical specimens showed widespread mucormycosis. An adolescent had meningococcemia-induced septic shock. During recovery, hemorrhagic colitis developed, which led to perforation. The subtotal colectomy specimen showed widespread mucormycosis. The laparotomy findings are typical (black necrotic tissue involving the bowel), and when seen in the immunocompromised patient, should make one suspect gastrointestinal mucormycosis. Aggressive surgical debridement of devitalized tissue augmented by intravenous antifungal medication is the mainstay of treatment.

Abdomen, Acute↗

PubMed1993

Fetal tumors associated with hydrops: the role of the pediatric surgeon.

Fetal tumors are being diagnosed with increasing frequency and great accuracy by antenatal ultrasound. High-output cardiac failure and hydrops indicate fetal distress. Management may be limited by the gestational age of the fetus. Our experience with three fetal tumors demonstrates the dilemma with respect to timing of delivery and prognosis. Following the diagnosis of a large sacrococcygeal tumor, a 22-week-gestation fetus became hydropic and died. Another fetus with a rapidly growing posterolateral chest wall mass required cesarean section delivery at 29 weeks gestation. Postnatal course was complicated by pulmonary hypoplasia, intratumoral hemorrhage, and death. The third fetus had an enlarging tumor in the right lobe of the liver. Poor biophysical profile and mild hydrops necessitated cesarean section delivery at 34 weeks. Right hepatic lobectomy was performed and the infant was subsequently discharged home at one month of age. The deleterious effects of the fetal tumor and the need for its removal have to be carefully weighed against the ability of the fetus to survive postnatally.

Adult↗

PubMed1992

The use of indium 111 leukocyte scans in children with inflammatory bowel disease.

Indium 111 leukocyte (WBC) scans have been used in the investigation of inflammatory bowel disease in recent years, but their use in children is not well described. We reviewed our experience with 281 indium 111 scans over an 8-year period in a total of 109 children with inflammatory bowel disease (Crohn's disease 70, ulcerative colitis 39). One hundred twenty-eight indium 111 scans done within 2 weeks of a radiographic contrast study, endoscopic examination, or surgical procedure were evaluated for diagnostic accuracy. Analysis showed that indium 111 scans were accurate when compared with conventional diagnostic tests and operative findings. This noninvasive imaging technique can play a useful role in the management of children with inflammatory bowel disease.

Adolescent↗

PubMed1992

Unbalanced translocation of chromosome 3p in Wilms' tumor.

Genetic studies in Wilms' tumor have most commonly shown a deletion involving band 13 on the p arm of chromosome 11 in association with aniridia. Structural rearrangements of chromosome 3p have been found in carcinoma of renal cell and lung origin but have not been previously reported in Wilms' tumors. We present two phenotypically normal, unrelated patients with Wilms' tumors, one of which was bilateral, in which cytogenetic analysis of the tumors showed an unbalanced translocation of the p arm of chromosome 3. Two biopsies were done in the patient with bilateral Wilms' tumor. The first biopsy specimen showed a translocation between chromosome 3 and 13 with partial trisomy of 3p and loss of material from 13q. The second biopsy three and a half months later again showed trisomy of chromosome 3p. The unilateral Wilms' tumor showed trisomy of 3p with partial loss of 7p. Neither patient showed a constitutional chromosomal abnormality and neither tumor showed any cytogenetic abnormality involving chromosome 11p. Quantitative DNA analysis was performed in the tumors of both patients. The bilateral Wilms' tumor was nearly diploid with a DNA index of 1.284 (mean ploidy, 2.45; SD, 0.854) while the unilateral Wilms' tumor was aneuploid with a DNA index of 1.531 (mean ploidy, 3.35; SD, 0.976). DNA analysis results are discussed in relationship to the chromosome abnormality seen on the karyotype analysis. These cytogenetic findings suggest that genetic oncogenesis in Wilms' tumor is heterogenous.

Aniridia↗

PubMed1991

Emergency separation of conjoined twins.

Female omphalopagus conjoined twins were successfully delivered vaginally and required emergency surgical separation shortly after birth for gastroschisis. Shared tissue included conjoined bowel; one twin also had a complex cloacal abnormality and patent urachus. A 2-year follow-up is presented. A review of the relevant literature confirms that this is the first example of gastroschisis conjoining omphalopagus twins.

Abdominal Muscles↗

PubMed1991

Hepatic artery pseudoaneurysms in acute pancreatitis.

The authors present a case of multiple intrahepatic pseudoaneurysms complicating acute gallstone pancreatitis, and they review the relevant literature. The complementary roles of ultrasonography, computed tomography and arteriography are illustrated. Although necrotizing vasculitis with resultant aneurysmal changes in peripancreatic vessels is a recognized complication of chronic pancreatitis, similar pseudoaneurysms have rarely been described in association with acute pancreatitis.

Acute Disease↗

PubMed1983

A survey of the available colorimetric indicators for Ca2+ and Mg2+ ions in biological experiments.

The binding of Ca2+ and Mg2+ ions to commercially available and easily synthesizable metallochromic indicators has been systematically examined at pH 7.35, temperature 37 degrees C, ionic strength 0.16, the conditions of blood plasma. The pCa and pMg midpoints of the colour changes of all the useful indicators are reported. In addition to the well-known indicators arsenzazo III, chlorophosphonazo III, antipyrylazo III, and murexide for Ca2+, and Eriochrome Black T and Eriochrome Blue SE for Mg2+, we draw attention to the values of oxyacetazo I, carboxyazo III, tropolone, methylthymol blue, Mordant Black 32, and the tetracyclines.

Azo Compounds↗

PubMed1982

Calcium ions and the control of proliferation in normal and cancer cells.

Several lines of evidence suggest tha Ca2+ ions control cell proliferation: Ca2+ entry into cytoplasm acts as a general mitogen; serum and serum-replacements induce Ca2+ influx; the Ca2+ concentrations in growth media required to support the proliferation of normal cells are much higher than those required for cancer cells; serum and growth factors reduce the Ca2+ requirements of normal cells; tumour promoters alter Ca2+ fluxes via a mechanism used principally by growth factors. Minor supporting evidence includes the effects of various drugs and viruses, and the behaviour of tumour cell mitochondria and intercellular junctions. It is still not possible to decide exactly where and when inside cells the critical effect of Ca2+ on proliferation occurs, but we discuss at length the practical problems of understanding Ca2+ movements in tissue-culture cells. Carried to its logical conclusion, present evidence suggests that an overridden or bypassed Ca2+ control process may be the key, common determinant of unrestrained proliferation in cancer cells.

Animals↗

PubMedDate not supplied

Determining the effect that consultation-liaison psychiatry in primary care has on family physicians' psychiatric knowledge and practice.

The impact of a community-based consultation-liaison (C-L) psychiatry service on family physicians' levels of psychiatric knowledge, diagnostic and treatment confidence, and patterns of referral to mental health care agencies was evaluated over a 12-month period. The physicians with long-term access to the C-L service had higher levels of psychiatric knowledge than those with short-term or no access. However, there was no evidence that the C-L service produced changes in the physicians' levels of clinical confidence, referral likelihood, or psychiatric knowledge during the evaluation period. Significant predictors of psychiatric knowledge were age (younger) and gender (women). The participating physicians were highly satisfied with the service and preferred it over other possible referral agencies. However, community C-L services in family practice appear to have a limited role in the provision of psychiatric care and are not an efficient way for improving family physicians' levels of psychiatric knowledge or altering their practices. The appropriate role of community C-L psychiatry may be as one component of a comprehensive service-delivery strategy integrated within ongoing, formal family-physician educational programs.

Adult↗