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Biomedical subjects

F Saunders

Publications and source records attributed to F Saunders.

At least 19 recordsLinked to original sources
PubMed2004

Rotational acceleration measurements--evaluating helmet protection.

PURPOSE: Current helmet testing standards do not address the rotational components of an impact to the head. We describe a new testing paradigm used to measure the rotational acceleration of a headform and a protective helmet following an impact to the head in the horizontal plane. This impact simulation allows for the testing of currently available head protection devices in conditions thought to be important for the generation of cerebral concussion. The degree to which a particular helmet dampens rotational acceleration, and thus protects against concussion, can be assessed. METHODS: Our testing device consists of a pneumatic piston that provides a measured impact to a standard headform. Four different helmets were tested using the described paradigm. RESULTS: Acceleration curves for each helmet and the corresponding headform are presented. CONCLUSIONS: Clear differences in rotational acceleration were demonstrated. Possible avenues of further investigation are discussed.

Acceleration↗
PubMed2001

The utility of plasma polymerase chain reaction for human herpes virus-6 among pediatric bone marrow transplant recipients: results of a pilot study.

We evaluated the utility of plasma polymerase chain reaction (PCR) for surveillance of human herpes virus 6 (HHV-6) infection among pediatric bone marrow transplant (BMT) recipients. We used a prospective, non-interventional design involving a study group and controls. BMT recipients and healthy controls were evaluated. BMT subjects had HHV-6 PCR done biweekly for 12 weeks post transplantation, while a single PCR test was done on controls. For the PCR assay, EDTA blood was collected and DNA extracted from whole blood and cell-free plasma using standard procedures. The PCR was first performed on DNA from whole blood and if a positive result was obtained, the test was repeated on the DNA from the plasma. Thirty BMT recipients (13 autologous and 17 allogeneic) were enrolled, on whom a total of 156 PCR tests were performed, while six tests were done on six healthy controls. The median age of BMT subjects was 6.2 years (range 0.5-17.5 years). The median age of the control subjects was 6.6 years (range 2-10 years). Among asymptomatic BMT patients who had PCR surveillance, the positivity rate was 3.3% (1/30) on whole blood and 0% (0/30) on plasma. None of the six healthy subjects had a positive PCR test on whole blood. During the period of the surveillance study, 14 patients had diagnostic evaluations for HHV-6 disease because of clinical symptoms. Two of these patients were diagnosed with disease associated with HHV-6 (graft failure and encephalitis) and had positive PCR tests on whole blood and plasma and whole blood and cerebrospinal fluid, respectively. We conclude that despite the fact that HHV-6 seropositivity rates are high among children, the frequency of HHV-6 plasma PCR positivity is low in pediatric BMT subjects who are asymptomatic for HHV-6 disease. Given that a positive test on plasma is consistent with active infection, this increases the utility of the PCR test as a diagnostic aid in evaluating syndromes presumed to be due to HHV-6 in pediatric bone marrow transplant recipients.

Adolescent↗
PubMed2001

A computer system for continuous long-term recording, processing, and analysis of physiological data of brain injured patients in ICU settings.

The objective of this project was to assemble and test a computer-based system for continuous long-term physiological data acquisition. The system would be used to study short-term (heart rate variability) and long-term (circadian rhythms) dynamics of physiological parameters in severely brain injured patients in ICU settings. A system has been built using open-source software and the Linux operating system as the platform. The system consists of three main parts: data acquisition, processing and analysis. The system was tested in ICU and experimental settings for long periods of time (up to 10 days of non-stop recording). The system appeared to function properly and accurately. Samples of the data according to the stages of acquisition-analysis process are presented in the paper. Avenues for the system use and development are discussed.

Brain Injuries↗
PubMed2001

Circadian rhythm of temperature in head injury.

It has been shown in a previous study that head injured patients appear to have a circadian rhythm of their body functions. This needed to be confirmed using additional data, better collection methods and analysis. Additional goals were to develop a method of detrending of physiological time series in order to improve rhythm detection when it may be hidden behind a low frequency trend and the creation of a computer system for data acquisition and analysis. The temperature data of 10 head injured patients was studied using the Iterative Cosinor method. In one case, prior to the Cosinor method, detrending of the data was used using a specially designed polynomial fitting technique. The Iterative Cosinor method showed circadian rhythms in nine out of 10 patients. After detrending, a rhythm was found in the data of the 10th patient as well. The periods of the rhythm were around, but were not equal to, 24 hours. The results show that comatose head injured patients have a circadian rhythm of their core temperature. The detection of a circadian rhythm may, in some cases, be improved by using a detrending technique. The deviation of the rhythm period from 24 hours suggests that the rhythms found in these patients are free-running, meaning that head injured patients are not synchronized with their surroundings.

Adolescent↗
PubMed2000

Matched unrelated bone marrow transplantation for combined immunodeficiency.

Bone marrow transplantation (BMT) from siblings is the treatment of choice for severe combined immunodeficiency (SCID). The objective of this study was to evaluate the efficiency of BMT from matched unrelated donors (MUD) in congenital immunodeficiencies when a sibling donor is unavailable. Sixteen consecutive patients with SCID (n = 9) and CID (n= 7), were referred for an unrelated donor search. Acceptable donors were found for all patients. Fifteen patients received busulfan and cyclophosphamide pretransplant conditioning. One patient had an early loss of graft and was reconditioned using cyclophosphamide and total body irradiation. The graft-versus-host disease (GVHD) prophylaxis used was methylprednisolone, cyclosporin A with or without methotrexate. Neutrophil engraftment was rapid and was achieved in all patients within a mean of 15.4 days. Only 13 episodes of fever were recorded shortly after BMT. GVHD of grade II or more was apparent in 2/9 (22%) of SCID patients and in 4/7 (57%) of CID patients. Overall survival was 75% with a mean follow-up of 47.4 months (range 18-101). Six out of nine SCID patients (67%) and 6/7 (86%) of CID patients are alive and well. Eleven patients had normal humoral immunity, and cell-mediated immunity as measured by flow cytometry and mitogenic responses, was intact in all patients. Intradermal candida skin test was positive in 9/10 patients tested. We conclude that BMT from MUD results in rapid engraftment and is therefore associated with a low rate of infection contributing to the improved survival rate. The protocol used is especially favorable for patients with combined immunodeficiency.

Anti-Bacterial Agents↗
PubMed2000

Quality of life and behavioral adjustment after pediatric bone marrow transplantation.

The purpose of this study was two-fold: to describe the quality of life and behavioral adjustment of survivors of pediatric bone marrow transplantation (BMT) prior to and 6 months post-BMT; and, to identify correlates of survivors' quality of life and behavioral adjustment. Participants were 26 children and adolescents who underwent BMT, and their mothers. At pre- and 6 months post BMT, mothers completed standardized measures of their children's behavioral adjustment, quality of life, and adaptive functioning. Self-report questionnaires were completed to determine levels of maternal anxiety and depression, and family functioning. Information was also gathered about demographic variables, medical history, and symptom severity. Children's overall quality of life improved 6 months post BMT and was most strongly associated with pre-BMT levels of family cohesion. Children's behavioral adjustment remained within the normal range across time and was associated with pre-BMT levels of family cohesion and child adaptive functioning. Mothers' psychological adjustment improved over time and was associated with quality of life, but unrelated to children's behavioral adjustment. Pre-BMT levels of family cohesion and child adaptive functioning appear to be important in understanding quality of life and behavioral adjustment of pediatric BMT survivors.

Adaptation, Psychological↗
PubMed2000

Medical urology.

Explore the source record for details and available documents.

Adult↗
PubMed1998

Cariostatic effects of a xylitol/NaF dentifrice in vivo.

Xylitol has been shown to reduce plaque acids, but its topical cariostatic effect has been equivocal. The purpose of the studies reported here was to optimise the xylitol/NaF combination in dentifrices for an improved anticaries activity. In the first study, the combination of 10 per cent xylitol with 1100 ppm F (NaF), 1100 ppm F (NaF), and placebo dentifrices were tested in a rat caries model to assess the cariostatic effect. The combination was significantly more effective than fluoride by itself (P = 0.05). The xylitol/NaF combination provided significantly more remineralisation of dentine than fluoride by itself. Collectively, results of these investigations confirm the improved anticaries effectiveness of the xylitol/NaF combination in a variety of animal and intra-oral models. A three-year clinical study confirmed these findings.

Acids↗
PubMed1996

Vascularity demonstrated by Doppler ultrasound and immunohistochemistry in invasive ductal carcinoma of the breast.

BACKGROUND: Vascularity is an important determinant of a tumour's ability to grow and disseminate. Breast tumour vascularity can be determined with doppler ultrasound (US) and by counting the vessels microscopically (microvascular density-MVD). The biologic characteristics of tumours based on their vascularity have not been extensively studied. METHOD: Preoperative US was performed on 207 patients with invasive ductal breast carcinomas (IDC). MVD was assessed immunohistochemically using polyclonal antisera against factor VIII and the proliferation rate was measured with Ki-67 polyclonal antisera. Histologic tumour characteristics and oestrogen receptor (ER) status were determined. Thermography was performed on 174 of the patients. RESULTS: Twenty-five percent of IDC demonstrated US-vascularity. US-vascular tumours were more likely to be node positive, and had a higher mitotic rate than avascular cancers. US-vascularity was more common in tumours with MVD greater than 80 vessels/250x field than those with fewer vessels. The proliferation rate, histologic grade III, and nuclear grade III were higher and ER positivity lower, but the differences were not statistically significant. US-vascular cancers were associated with significantly more thermographic abnormalities. The cancer recurrence rate at three years was higher in patients with vascular cancers although the difference was not statistically significant. CONCLUSION: US appears to be a simple, non-invasive method of identifying vascular cancers associated with factors indicating a poor prognosis.

Adult↗
PubMed1996

Health of grandmothers raising children of the crack cocaine epidemic.

OBJECTIVES: Approximately 3.2 million children live with their grandparents or other relatives-a 40% increase in 10 years. This article presents selected findings from an exploratory study of the experience of 71 African-American women raising their grandchildren because of the crack epidemic. METHODS: The study was designed to describe the caregivers' self-reported physical and emotional health status and health-care-related behaviors through a combination of qualitative and quantitative data collected during two in-home interviews. RESULTS: Most respondents rated their health as good or fair, with little change over the previous year, or since caregiving began. Employed women were more likely not only to rate their health as excellent or good, but also to report that their health had deteriorated over the previous year. Other subgroups showing evidence of deteriorating health were those caring for several grandchildren and great-grandmothers. Caregivers without a confidante reported a positive health change. Although 80% of the sample reported receiving regular health care, one third had not been to the doctor in 3 years. Half reported breaking a medical appointment in the last year, most often because of caregiving demands. CONCLUSIONS: These findings have relevance for physicians and other health-care providers because they suggest that many grandparent caregivers may be or soon become the "hidden patients" of the crack cocaine epidemic.

Adult↗
PubMed1994

Concurrent RhGM-CSF does not offset myelosuppression from intensive chemotherapy: randomized placebo-controlled study in childhood acute lymphoblastic leukemia.

To determine whether recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) can offset the myelosuppressive effects of intensive chemotherapy, we carried out a double-blind placebo-controlled trial in which 40 patients with acute lymphoblastic leukemia (ALL) were randomized into two groups of 20 each. One group received rhGM-CSF (5.5 micrograms/kg SC) coadministered with chemotherapy and the other, placebo coadministered with chemotherapy from day 5 to day 11 and from day 19 to day 25 of the 28-day intensification phase of our institutional high-risk protocol for childhood ALL. The results indicate that, at the dose and schedule used, rhGM-CSF did not prevent neutropenia or shorten the number of days required to complete this phase of therapy. In addition, the treated and placebo groups showed no significant difference in absolute neutrophil counts, number of days with neutropenia, number of days with fever, number of days spent in hospital, or number of days on antibiotics during the 28-day study period. There was also no difference between the two groups in the number, type, or severity of infectious episodes. Two of 20 patients in the treatment group have relapsed, whereas none of the patients in the placebo group has yet relapsed (follow-up: 3-37 months), but these events were not statistically significant. We conclude that treatment with rhGM-CSF at the dose and schedule employed is not clinically beneficial.

Adolescent↗
PubMed1992

A multicenter, randomized, controlled trial to evaluate the effect of prophylactic octreotide on ERCP-induced pancreatitis.

Eight-four patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) were randomized to receive 100 micrograms of octreotide intravenously immediately prior to ERCP, and 100 micrograms subcutaneously 45 min after the initial dose, or placebo. Amylase, lipase, and glucose were measured and clinical assessment was performed before, and 2 and 24 h after, ERCP. We define clinical pancreatitis as the combination of elevated amylase or lipase with abdominal pain and tenderness. Interim analysis in 84 patients revealed an 11% incidence of clinical pancreatitis in the control group and 35% in the treatment group (p < 0.01). There were no differences in either group with respect to sphincterotomy, gender, age, duration of ERCP, number of cannulations of the pancreatic duct, degree of duct injection, or the volume of contrast injected. Analysis of group differences stratified by sphincterotomy revealed the following: 1) In patients who did not undergo a sphincterotomy, there was a significantly higher rate of pancreatitis in the treatment group [10/17 (59%) versus 1/17 (6%) RR 10.0 (95% CI 1.4-69.8)]. 2) Sphincterotomy reduced the rate of pancreatitis in patients who received octreotide from 10/17 (59% no sphincterotomy), to 3/20 (15% sphincterotomy) (p = 0.01), which equals the rate in patients who received placebo and underwent sphincterotomy [4/25 (16%)]. 3) Although the incidence of pancreatitis was higher in the treatment group, octreotide may reduce the severity of pancreatitis measured by the number of days NPO (Wilcoxon rank sum, p = 0.02), length of stay after ERCP (p = 0.13), the number of days of pain (p = 0.11), and the degree of amylase elevation (p = 0.04). We conclude that: 1) Octreotide appears to increase the incidence of pancreatitis when given prophylactically for diagnostic ERCP. 2) Although pancreatitis was more common in the octreotide group, it was less severe than the placebo group. 3) Sphincterotomy may afford protection against pancreatitis in patients who received octreotide. 4) We cannot recommend the use of prophylactic octreotide during diagnostic or therapeutic ERCP.

Amylases↗
PubMed1990

Hodgkin's disease in children: treatment with MOPP and low-dose, extended field irradiation without laparotomy. Late results and toxicity.

The 10 year results of a trial of bimodal treatment of Hodgkin's disease in children with 6 cycles of MOPP and low-dose extended field irradiation, without staging laparotomy, were for 57 children in all stages as follows: survival 85%, relapse-free survival 80%, and survival-free of second relapse 86%. There were three fatal toxic events, two due to viral infection and one to a second malignant tumor (NHL). Three other patients developed a second malignant tumour, and one developed a thyroid adenoma. No patient developed acute leukemia. These results are compared with the results of treatment of surgically staged children by extended field irradiation alone, with bimodal treatment reserved for relapse or advanced disease at diagnosis. Initial bimodal treatment improved the overall 10 year survival free from a second relapse rate by 20% (86% vs. 66%). No major difference in treatment toxicity between these two groups has emerged during the first 10 years of follow-up. We conclude that, except for favourable CS-1 presentations, children with Hodgkin's disease confined to the lymphatic system should be given bimodal treatment, but that the least morbid effective combination remains to be determined.

Adolescent↗
PubMed1989

Topical nitroglycerin: a potential treatment for impotence.

The effect of 2 per cent nitroglycerin paste applied to the penile shaft of impotent subjects was evaluated in a placebo controlled double-blind study under laboratory conditions. After application of nitroglycerin paste or a placebo ointment base, penile tumescence was recorded through a strain gauge transducer while subjects viewed an erotic video presentation. Relative to the placebo paste the number of subjects demonstrating an increase in penile circumference after nitroglycerin (18 of 26) was significantly different than all other outcome possibilities (p less than 0.05). Noninvasive vascular assessment by ultrasonography demonstrated an increase in diameter and blood flow in the cavernous arteries after application of nitroglycerin paste. Nitroglycerin paste increases blood flow in the cavernous arteries and improves tumescence after erotic stimulation. This agent may represent a new therapy for impotence.

Administration, Topical↗
PubMed1985

The virulence of clinical and environmental isolates of Campylobacter jejuni.

The virulence of Campylobacter jejuni and C. coli isolated from various water sources was compared with that of clinical strains by in vitro assays of adhesion, invasion and cytotoxicity to HeLa cells. Variation in degree of attachment was observed, but this did not appear to be related to strain source, However, water strains were less invasive and less cytotoxic to HeLa cells than clinical strains as shown by immunofluorescence and electron microscopy. These differences were particularly evident between clinical and water isolates of the same serotype and biotype implicated in an outbreak of campylobacter enteritis in a school. The enhanced virulence of the clinical isolates, possibly induced by passage, was confirmed by colonization tests on infant mice.

Adhesiveness↗