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Biomedical subjects

R Fisher

Publications and source records attributed to R Fisher.

At least 91 records · Page 5Linked to original sources
PubMed1996

Cystic hygroma: comparison between prenatal and postnatal diagnosis.

Antenatal diagnosis of congenital malformation often leads to opportunities for intervention in the pregnancy that may have a profound effect on the outcome of the fetus. The accuracy of the diagnostic technique is a critical factor in judging the appropriateness of such interventions. This article reports the current accuracy of prenatal ultrasound diagnosis of cystic hygroma (CH) in a region with a population of 3.5 million and an annual birth rate of 52,000. During a 32-month period (to December 1994), 113 diagnoses of CH were reported to the South East Thames Regional Congenital Malformation Registry. Eighty-nine diagnoses were made prenatally and 24 were made postnatally (at delivery or postmortem). The number of confirmed cases of CH was 52 (46% total diagnoses). The prenatal diagnoses were established at a mean gestational age of 19 weeks. Fifty-six (63%) pregnancies with a prenatal diagnosis of fetal CH were terminated; in only 25% of these was the presence of CH confirmed after termination. Overall, of the 89 prenatal diagnoses, 28 (32%) were confirmed, 45 (50%) were incorrect, and 16 (18%) could not be confirmed or refuted. Only 24% of fetuses with a prenatal diagnosis of CH were live born. The survival rate at 1 year for the live-born infants with CH in this series was 88%. The diagnosis of fetal CH has a recognised association with chromosomal abnormalities, and consequently may lead to termination of the pregnancy. A potential error rate of almost 70% in the prenatal ultrasound diagnosis of this condition requires clinicians to adopt a more cautious approach to the management of the fetus with "cystic hygroma."

Abortion, Eugenic↗
PubMed1996

Impact of antenatal diagnosis on incidence and prognosis in abdominal wall defects.

The authors review data from the Congenital Malformation Registry in South East Thames regarding fetal abdominal wall defects. Over 24 months, 80 cases were observed (40 gastroschisis, 40 exomphalos). Live-born infants with gastroschisis had few associated anomalies and an excellent prognosis (83% survival rate). Exomphalos is associated with an increased rate of life-threatening anomalies and chromosomal defects. The latter cases often are terminated prenatally. If these cases are excluded, the 1-year survival rate for liveborn infants with exomphalos is favorable (close to 80%). Fetuses in whom gastroschisis and exomphalos are identified by ultrasonography but who have no associated life-threatening chromosomal anomalies should have a favorable prognosis.

Abdominal Muscles↗
PubMed1996

Molecular Diagnostics in Pediatric Acute Lymphoblastic Leukemia.

Remarkable progress has been made in identifying the molecular lesions involved in the pathogenesis of pediatric acute lymphoblastic leukemia. Efforts to clone the genes involved in chromosomal translocations have led to the isolation of a number of novel proto-oncogenes. The biochemical characterization of the encoded products has helped to elucidate important regulatory pathways involved in cellular differentiation, proliferation, or control of cell death, and has helped to define how alterations in these pathways contribute to leukemogenesis. In addition, these efforts have led to the development of molecular-based assays for the identification of the specific molecular lesions. Clinical application of these assays has rapidly led to the realization that molecular lesions can identify distinct patient subgroups with predictable clinical features and responses to therapy. In this review, the emerging role of molecular diagnostics in the clinical management of pediatric patients with acute lymphoblastic leukemia is discussed.

Journal Article↗
PubMed1996

Lipoprotein lipase gene mutations D9N and N291S in four pedigrees with familial combined hyperlipidaemia.

The role of the lipoprotein lipase (LPL) gene in familial combined hyperlipidaemia (FCH) is unclear at present. We screened a group of 28 probands with familial combined hyperlipidaemia and a group of 91 population controls for two LPL gene mutations, D9N and N291S. LPL-D9N was found in two probands and one normolipidaemic population control. LPL-N291S was found in four probands and four population controls. Subsequently, two pedigrees from probands with the D9N mutation and two pedigrees from probands with the N291S mutation were studied, representing a total of 24 subjects. Both LPL gene mutations were associated with a significant effect on plasma lipids and apolipoproteins. Presence of the D9N mutation (n = 7) was associated with hypertriglyceridaemia [2.69 +/- 1.43 (SD) mmol L-1] and reduced plasma high-density lipoprotein cholesterol (HDL-C) concentrations (0.92 +/- 0.21 mmol L-1) compared with 11 non-carriers (triglyceride 1.75 +/- 0.64 mmol L-1; HDL-C 1.23 +/- 0.30 mmol L-1, P = 0.03 and P = 0.025 respectively). LPL-D9N carriers had higher diastolic blood pressures than non-carriers. LPL-N291S carriers (n = 6) showed significantly higher (26%) apo B plasma concentrations (174 +/- 26 mg dL-1) than non-carriers (138 +/- 26 mg dL-1; P = 0.023), with normal post-heparin plasma LPL activities. Linkage analysis revealed no significant relationship between the D9N or N291S LPL gene mutations and the FCH phenotype (hypertriglyceridaemia, hypercholesterolaemia or increased apo B concentrations). It is concluded that the LPL gene did not represent the major single gene causing familial combined hyperlipidaemia in the four pedigrees studied, but that the LPL-D9N and LPL-N291S mutations had significant additional effects on lipid and apolipoprotein phenotype.

Adult↗
PubMed1996

Cognitive effects of resecting basal temporal language areas.

Electrical stimulation of the basal temporal region of the dominant hemisphere before partial temporal lobectomy for epilepsy sometimes produces temporary interruption of language function, but the significance of removal of this area is unknown. We evaluated the correlation between resection of the basal temporal language areas (BTLA) and certain types of postoperative language deficits. In a population of 25 patients, we mapped the inferolateral temporal lobe with cortical electrical stimulation, verifying the positions of the stimulating electrodes with three-dimensional computed tomography (CT). Eighty percent of the patients developed transient language deficits with stimulation, particularly with tests of confrontation naming and comprehension. BTLA was primarily located in the fusiform gyrus, from 1 to 9 cm from the temporal tip. At testing 6-12 months after operation, patients with BTLA resection performed worse (mean 9% decrease) than those with no BTLA resection (mean 4% improvement) on tests of confrontation naming (p = 0.03). Resection size accounted for less of the variance in decrease in confrontation naming than did resection of the BTLA. Tests of performance I.Q. (PIQ), verbal I.Q. (VIQ), or recognition memory for word and verbal learning showed no significant difference between these groups. Most patients do not have language decrease with removal of basal temporal lobe 5-6 cm from the tip, even with removal of BTLA. Some patients, however, have persistent decrease in naming.

Adolescent↗
PubMed1996

Newer antiepileptic drugs as monotherapy: data on vigabatrin.

Studies examining the use of vigabatrin as monotherapy for the treatment of epilepsy are relatively scarce, and of the few that have been reported, only two were of sufficient size to provide definitive data. In both trials, vigabatrin was compared with carbamazepine for efficacy and safety. In one of these studies, carbamasepine was found to be more effective than vigabatrin in reducing seizure frequency, and the two were found to be comparably efficacious in the other study. What differed significantly, however, was vigabatrin's favorable safety profile. Vigabatrin appears to be a reasonable choice for single-drug therapy in the treatment of certain types of seizures. In other patients, it remains useful as an adjunct to other antiepileptic drugs.

Adolescent↗
PubMed1995

Analysis of failure following definitive radiotherapy for invasive transitional cell carcinoma of the bladder.

PURPOSE: To assess prognostic factors for bladder relapse and distant failure following definitive radiotherapy for invasive transitional cell carcinoma (TCC) of the bladder. METHODS AND MATERIALS: Retrospective review of patients treated in the period 1977 to 1990 by definitive radiotherapy. The factors studied included age, sex, T stage, histological grade, tumor multiplicity, ureteric obstruction, total radiation dose, and use of neoadjuvant chemotherapy. The endpoints studied were bladder relapse and distant failure. RESULTS: There were 342 patients with a mean follow-up time of 7.9 years. Bladder relapse was observed in 159 patients. The overall actuarial bladder relapse rate at 5 years was 55% (SE = 3%). Prognostic factors for a higher bladder relapse rate were: tumor multiplicity (p < 0.001), presence of ureteric obstruction (p = 0.001), and higher T stage (p = 0.044). Distant failure occurred in 39 patients. The overall actuarial distant failure rate at 5 years was 28% (SE = 3%). Prognostic factors for a higher distant failure rate were: ureteric obstruction (p = 0.003) and higher T stage (p = 0.030). CONCLUSION: In our study, patients with invasive bladder TCC fell into distinct prognostic groups determined by the three independent factors, ureteric obstruction, tumor multiplicity, and T stage. These factors provided estimated risks of bladder relapse by 5 years which ranged from 34% to 91%. Knowledge of these prognostic factors can help in the selection of patients more suited for bladder preservation by definitive radiotherapy.

Actuarial Analysis↗
PubMed1995

Risk-based prenatal screening for trisomy 18 using alpha-fetoprotein, unconjugated oestriol and human chorionic gonadotropin.

Nine centres collaborated to examine the feasibility of a screening method for trisomy 18 that was based on assigning individual risk, using a combination of maternal age and measurements of alpha-fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotropin (hCG). Second-trimester measurements of these analytes were obtained from 94 trisomy 18 pregnancies. In the 89 pregnancies without an associated open defect, the median levels for AFP, uE3, and hCG were 0.65, 0.43 and 0.36 multiples of the unaffected population median, respectively. The strongest individual predictor of risk for trisomy 18 was uE3, followed by hCG, AFP, and maternal age, in that order. Using a method of individual risk estimation that is based on the three markers and maternal age, 60 per cent of pregnancies associated with trisomy 18 would be detected at a risk cut-off level of 1:100, with a false-positive rate of about 0.2 per cent. One in nine pregnancies identified as being at increased risk for trisomy 18 would be expected to have an affected pregnancy. This risk-based screening method is more efficient than an existing method that is based on fixed analyte cut-off levels. Even though the birth prevalence of trisomy 18 is low, prenatal screening can be justified when performed in conjunction with Down syndrome screening and when a high proportion of women offered amniocentesis have an affected fetus.

Adult↗
PubMed1995

Response of brain tumors to chemotherapy, evaluated in a clinically relevant xenograft model.

Chemotherapy for brain tumors remains unsatisfactory. Despite increasing participation in clinical trials, there is a clear need for pre-clinical models. Heterotransplantation of surgical specimens directly into the anterior chamber of the nude mouse eye has been demonstrated to produce evaluable xenografts. Drug access in this model is considered to mimic the blood-brain barrier. Five clinical specimens in 3 children with primitive neuroectodermal tumor/medulloblastoma were the sources of 293 intraocular xenografts (5 cohorts by source). Each tumor-bearing mouse received 1 of 5 drugs or normal saline, by intraperitoneal injection, weekly for 5 weeks. Response was monitored for up to 22 weeks, using a staging system which estimates the proportion of the anterior chamber filled by tumor. Results were analysed both as response rates (shrinkage in excess of 50%) at the conclusion of the treatment course and as time to tumor progression by the life table method. Comparison of response rates within cohorts by source of xenografts (exact chi-square test for overall and 2-sided Fisher's exact test for paired comparisons) indicated cyclophosphamide to be the most effective single agent. In logrank analyses cyclophosphamide achieved significantly longer delays to progression than all other drugs in one cohort and longer delays than all but diaziquone in 2 other cohorts. The intraocular xenograft model is a clinically relevant system for the study of therapeutic agents in brain tumors. The effectiveness of intensive dosage cyclophosphamide in a model dependent on access across the blood-aqueous barrier is important and consistent with recent clinical data.

Animals↗
PubMed1995

The use of implants for orthodontic correction of an open bite.

This case illustrates the integration of maxillofacial surgery, orthodontics, prosthodontics and periodontics in the treatment of an adult male. A traumatic injury to the lower jaw was the stimulus for the patient to seek orthodontic correction of a severe malocclusion including crossbites and an anterior open bite. The loss of a large portion of the anterior alveolar process of the lower jaw including six teeth was corrected with an implant bearing prosthesis which was subsequently used as anchorage to correct the malocclusion. Through the combined efforts of the above disciplines, properly orchestrated, this patient was treated in an effective and successful manner.

Adult↗
PubMed1995

Mammary cancer in transgenic mice expressing insulin-like growth factor II (IGF-II)

The effect of insulin-like growth factor II (IGF-II) on tumour development in the mouse mammary gland was studied. To promote extra IGF-II expression in the mammary gland, sheep beta-lactoglobulin regulatory elements were attached to the coding regions of the mouse Igf-2 gene and injected into the pronuclei of mouse zygotes. Mammary tumours developed in each of the four independent lines of mice which expressed transgene IGF-II in the gland. Tumours from two of the lines grew after transplantation to both male and female hosts. Primary tumours contained stromal and epithelial regions, but the tumours were dominated by mammary adenocarcinoma after transplantation. The tumours expressed high levels of Igf-2 mRNA transcribed from the integrated transgenes.

Adenocarcinoma↗
PubMed1995

Ewing's sarcoma as a second malignant neoplasm in a child previously treated for Wilms' tumor.

PURPOSE: Second malignant neoplasms (SMNs) are a rare occurrence after the successful treatment of childhood cancer. For survivors of Wilms' tumor, the 10-year cumulative risk of developing an SMN has been estimated to be 1%. Bone sarcomas arising within the radiation field are a common occurrence, yet Ewing's sarcoma has been rarely reported as an SMN. PATIENTS AND METHODS: A 10-year-old girl presented with dyspnea 5 years after the diagnosis of stage III favorable histology Wilms' tumor and was found to have a right intrathoracic mass arising from the eighth and ninth ribs. The mass was located at the edge of the previous radiation field. RESULTS: Tumor cytogenetics and immunocytochemistry were helpful in establishing the diagnosis of Ewing's sarcoma. Treatment included combination chemotherapy, with hematopoietic growth factor support, and excluded anthracyclines and radiotherapy. More than 1 year after the diagnosis of Ewing's sarcoma, the patient has completed therapy with no evidence of disease. CONCLUSIONS: This is the first report to our knowledge of Ewing's sarcoma arising in the irradiation field of a patient treated previously for Wilms' tumor.

Child↗
PubMed1995

Breast cancer following treatment for Hodgkin's disease: the need for screening in a young population. Australasian Radiation Oncology Lymphoma Group (AROLG)

Several recent publications have highlighted the issue of an increased risk of breast cancer in women treated with radiotherapy, chemotherapy, or combined modality therapy for Hodgkin's disease. The risk is greatest in women 30 years or younger at the time of treatment. In the Australasian Radiation Oncology Lymphoma Group database, 60% of women fell into this age category. This article reviews the available data pertaining to induction of breast cancer by radiotherapy for Hodgkin's disease. Breast examination should now be an integral part of the long term follow up for these women. There is also a case for the use of screening mammography. Any breast mass developing subsequent to treatment for Hodgkin's disease should be regarded with a high index of clinical suspicion and, accordingly, biopsies should be performed in the majority of cases, even when mammography is negative.

Adult↗
PubMed1995

Clobazam, oxcarbazepine, tiagabine, topiramate, and other new antiepileptic drugs.

Clinical investigators recently have studied at least 21 new antiepileptic drugs (AEDs) in people with epilepsy. This review briefly examines 15 of these new AEDs: clobazam (CLB), dezinamide, flunarizine (FNR), loreclezole, milacemide (MLM), MK-801, nafimidone, ORG-6370, oxcarbazepine (OCBZ), progabide (PGB), ralitoline, stiripentol, tiagabine (TGB), topiramate (TPM), and zonisamide (ZNS). CLB, PGB, and TGB represent agents that act on the GABA system, and MLM acts on the glycine system. MK-801 and ZNS (in part) are excitatory amino acid antagonists, and FNR is a calcium-channel antagonist. OCBZ is a keto analogue of carbamazepine, which is not metabolized to the epoxide and may have fewer side effects. The remaining agents are novel compounds with a variety of suspected mechanisms. TPM appears especially effective for intractable partial seizures but has a high incidence of cognitive side effects. None of these new AEDs is useful for all patients with inadequate seizure control or ongoing toxicity. The role of each will require further clinical study and experience.

Animals↗