Biomedical subjects

J Fitzsimmons

Publications and source records attributed to J Fitzsimmons.

At least 19 recordsLinked to original sources

PubMed2000

Poliomyelitis surveillance: the model used in India for polio eradication.

Poliomyelitis surveillance in India previously involved the passive reporting of clinically suspected cases. The capacity for detecting the disease was limited because there was no surveillance of acute flaccid paralysis (AFP). In October 1997, 59 specially trained Surveillance Medical Officers were deployed throughout the country to establish active AFP surveillance; 11,533 units were created to report weekly on the occurrence of AFP cases at the district, state and national levels; timely case investigation and the collection of stool specimens from AFP cases was undertaken; linkages were made to support the polio laboratory network; and extensive training of government counterparts of the Surveillance Medical Officers was conducted. Data reported at the national level are analysed and distributed weekly. Annualized rates of non-polio AFP increased from 0.22 per 100,000 children aged under 15 years in 1997 to 1.39 per 100,000 in 1999. The proportion of cases with two adequate stools collected within two weeks of the onset of paralysis increased from 34% in 1997 to 68% in 1999. The number of polio cases associated with the isolation of wild poliovirus decreased from 211 in the first quarter of 1998 to 77 in the first quarter of 1999. Widespread transmission of wild poliovirus types 1 and 3 persists throughout the country; type 2 occurs only in Bihar and Uttar Pradesh. In order to achieve polio eradication in India during 2000, extra national immunization days and house-to-house mopping-up rounds should be organized.

Adolescent↗

PubMed1999

Estimated fetal weight. Maternal vs. physician estimate.

OBJECTIVE: To compare the accuracy of fetal weight estimation as determined by laboring, parous women vs. by a physician using abdominal palpation. STUDY DESIGN: Four hundred seventy-one laboring, term, parous women underwent abdominal palpation by a physician and were subsequently asked to estimate the weight of their fetus, unaware of the physician's determination. Mean absolute error and percentage of fetal weight estimates within 10% of actual birth weight for both maternal and physician estimates were compared using Student's t test. Linear regression analysis was employed to determine whether maternal age, parity and race influenced the accuracy of the maternal estimation. In a similar fashion, level of physician training was analyzed to determine its impact on clinical fetal weight estimations. RESULTS: There were no statistical differences in mean absolute error (331 vs. 324 g) or percentage of fetal weight estimates within 10% of actual birth weight (62% vs. 60.9%) between maternal and physician determinations, respectively. Maternal age, race and parity did not influence the woman's ability to accurately predict fetal weight. Greater physician experience did not improve clinical fetal weight determinations. CONCLUSION: Parous women can subjectively estimate the weight of their fetus just as accurately as a physician using abdominal palpation. Neither maternal factors nor physician experience improves fetal weight estimations.

Adult↗

PubMed1998

An efficient motion estimator with application to medical image registration.

Image registration is a very important problem in computer vision and medical image processing. Numerous algorithms for registering single and multi-modal image data have been reported in these areas. Robustness as well as computational efficiency are prime factors of importance in image data registration. In this paper, a robust/reliable and efficient algorithm for estimating the transformation between two image data sets of a patient taken from the same modality over time is presented. Estimating the registration between two image data sets is formulated as a motion-estimation problem. We use a hierarchical optical flow motion model which allows for both global as well as local motion between the data sets. In this hierarchical motion model, we represent the flow field with a B-spline basis which implicitly incorporates smoothness constraints on the field. In computing the motion, we minimize the expectation of the squared differences energy function numerically via a modified Newton iteration scheme. The main idea in the modified Newton method is that we precompute the Hessian of the energy function at the optimum without explicitly knowing the optimum. This idea is used for both global and local motion estimation in the hierarchical motion model. We present examples of motion estimation on synthetic and real data (from a patient acquired during pre- and post-operative stages) and compare the performance of our algorithm with that of competing ones.

Algorithms↗

PubMed1996

Graft surveillance and angioplasty prolongs dialysis graft patency.

BACKGROUND: In the United States of America, vascular access complications are the most frequent cause of death among patients with end-stage renal disease on hemodialysis. The majority of American patients with end-stage renal disease have prosthetic grafts for access. The most common complication of prosthetic graft fistulas is thrombosis. To prolong graft life and decrease the frequency of operations, a university-based dialysis unit adopted a policy of graft surveillance by measuring venous resistance, followed by fistulagram and percutaneous dilatation of identified stenoses. The purpose of this retrospective study is to determine if this policy affected graft patency and graft life. STUDY DESIGN: This retrospective review compares outcomes for two years before adoption of this policy (control group, 210 patients) with the outcomes for three years after adoption (study group, 260 patients). Fifty (24 percent) of the control group and 71 (27 percent) of the study group were defined as "complicated" patients because they underwent more than one intervention over any 12-month period. RESULTS: The 50 complicated patients in the control group underwent 104 operations for thrombosis over two years, 1.04 thrombotic episodes and operations per patient year. Seventy new grafts were placed with a mean primary patency of 3.9 months. Mean graft survival time was 6.3 months. The 71 complicated patients in the study group underwent 111 fistulagrams, 80 angioplasties, and 110 operations over three years, for 0.52 thrombotic episodes per patient year (p < .001). Forty-five new grafts were placed with a primary patency of 11.5 months (p < .001). Mean graft survival time was 15.8 months (p < .001). CONCLUSIONS: This retrospective study demonstrates the effectiveness of a policy of graft surveillance and percutaneous treatment of graft stenosis in prolonging primary surgical patency and graft survival.

Angioplasty, Balloon↗

PubMed1994

Fetal ear measurements in the prenatal detection of trisomy 21.

Although prominent fetal nuchal folds, short long bones, echogenic bowel, and renal pelviectasis have been shown to be associated with trisomy 21, none has acceptable diagnostic efficacy. Diminished fetal ear lengths measured by ultrasound have recently been reported as yet another potential morphological marker for the prenatal detection of trisomy 21. To investigate this further, we measured ear lengths and widths of normal (n = 107) and trisomy 21 (n = 25) second-trimester formalin-preserved fetuses. The normal ear growth characteristics are described and compared with those of trisomy 21 fetuses. The normal fetal ear shape, not unlike that of the neonates, manifested a marked variation. When the ear lengths and widths were regressed against gestational age, the slopes of the regression lines for the two groups were found to be different (P < 0.001). However, despite the statistically significant difference between the ear sizes of normal and trisomy 21 fetuses, the wide range of normal variation seen at each gestational age means that the fetal ear measurements are not diagnostically helpful.

Down Syndrome↗

PubMed1994

Conjugated deferoxamine reduces blood-brain barrier disruption in experimental optic neuritis.

The purpose of this paper was to investigate the role of deferoxamine (DFO) scavenging of hydroxyl radical (.OH) on disruption of the blood-brain barrier (BBB) and demyelination in experimental optic neuritis. Eighteen strain-13 guinea pigs were sensitized for experimental allergic encephalomyelitis. Nine animals received 100 mg/kg of hydroxyethyl starch-conjugated (HES) DFO by daily intraperitoneal injection commencing the day of antigenic sensitization. Nine paired litter mates received daily IP injections of HES. Serial fat-suppressed magnetic resonance imaging of the optic nerves was obtained with a T2 weighting (T2w) to evaluate demyelination and after intravascular administration of Gd-DTPA to evaluate BBB disruption. The intensity of Gd-DTPA enhancement and T2w signal of the optic nerves was quantitated 3, 7, 10 and 14 days after antigenic sensitization. Animals were then sacrificed and the optic nerves processed for light and transmission electron microscopy with ultracytochemical localization of endogenous hydrogen peroxide (H2O2) and immunogold colocalization of extravasated serum albumin. The area of the optic nerve head, intensity of toluidine blue staining, and the cellular infiltrate were digitized and quantitated. Administration of HES-DFO significantly reduced the intensity of Gd-DTPA enhancement in the optic nerves of HES-DFO-treated animals compared to paired control HES animals (p = 0.0236), with the mean difference between control and treated animals of 19.39. The difference in T2w signal was not significant (p = 0.39), with a mean difference between control and treated animals of -5.51. The intensity of toluidine blue staining of optic nerve specimens was slightly less with HES-DFO compared to untreated animals (mean pair difference 2.48), and the inflammatory infiltrate was reduced with HES-DFO compared to untreated animals (mean pair difference = 61.57); these differences were not statistically significant. In the optic nerve specimens of both groups cerium perhydroxide-derived H2O2 reaction product was evident in a predominantly perivascular and perineural distribution. Immunogold-labeled serum albumin showed extravasation at foci of perivascular inflammation in both the presence and absence of H2O2-derived reaction product. Conjugated DFO reduces disruption of the BBB, as measured by Gd-DTPA enhancement, suggesting the .OH radical generated from perivascular H2O2 may play a role in alterations of vascular permeability in experimental optic neuritis.

Animals↗

PubMed1994

Fat-suppressed MR of the orbit and cavernous sinus: comparison of fast spin-echo and conventional spin-echo.

PURPOSE: To compare T2-weighted fat-suppressed fast spin-echo imaging with fat-suppressed conventional spin-echo imaging in the detection of normal intraorbital and pericavernous anatomy and orbital disease, and to determine the efficacy of fat saturation with T2-weighted fast spin-echo imaging of the cavernous sinus. METHODS: Contrast-to-noise ratios of normal intraorbital anatomy were calculated and compared in 10 consecutive patients using fat-suppressed fast spin-echo and conventional spin-echo T2-weighted images. Contrast-to-noise ratios of common intraorbital lesions were calculated and compared using fat-suppressed fast spin-echo and fat-suppressed conventional spin-echo. Qualitative evaluation was performed and compared for normal intraorbital anatomy using both fat-suppressed fast spin-echo and fat-suppressed conventional spin-echo in 16 patients. Qualitative evaluation for the detection of normal anatomic structures of the pericavernous region was performed and compared using fast spin-echo with and without fat suppression and fat-suppressed conventional spin-echo T2-weighted images in 16 patients. Fat saturation was performed using standard commercially available chemical saturation technique. RESULTS: Reduced imaging time allowed more acquisitions for fat-suppressed fast spin-echo images, which significantly improved visibility of intraorbital and pericavernous anatomy over fat-suppressed conventional spin-echo. Anatomic visibility was also improved because of reduced motion, phase encoding, and susceptibility artifacts. There was no significant difference between contrast-to-noise ratios for fat-suppressed fast spin-echo and fat-suppressed conventional spin-echo imaging of the lateral and medial rectus muscles. Contrast-to-noise ratios of fat suppressed fast spin-echo of orbital disease was significantly greater than contrast-to-noise ratios of fat-suppressed conventional spin-echo. Detection of several normal anatomic structures of the pericavernous region was significantly improved with non-fat-suppressed fast spin-echo over fat-suppressed fast spin-echo because of significantly reduced magnetic susceptibility artifact. CONCLUSIONS: Fat-suppressed fast spin-echo is superior to fat-suppressed conventional spin-echo for T2-weighted orbital imaging. Non-fat-suppressed fast spin-echo is the preferred pulse sequence for T2-weighted imaging of the cavernous sinus because of the minimal susceptibility artifact.

Adipose Tissue↗

PubMed1994

Reversals of blood-brain barrier disruption by catalase: a serial magnetic resonance imaging study of experimental optic neuritis.

PURPOSE: To investigate serially the role of catalase detoxification of endogenous H2O2 in the disruption of the blood-brain barrier (BBB) and demyelination of experimental optic neuritis. METHODS: Serial contrast-enhanced magnetic resonance imaging (MRI) of the optic nerves (T1 weighted) and T2 weighted MRI without contrast were performed on 18 guinea pigs 3 to 14 days after sensitization with central myelin for experimental allergic encephalomyelitis. Sex and age-matched littermates were paired and sensitized with the identical antigenic emulsion. To detoxify endogenous hydrogen peroxide (H2O2), animals received daily intraperitoneal injections of polyethylene glycol (PEG)-catalase at a dose of 12,000 U/kg per day for 3 days, then 1,200 U/kg daily for the next week, commencing 3 days after antigenic sensitization. Littermates received an equal volume of preservative-free saline. The intensity of gadolinium-DTPA (Gd-DTPA) enhancement was quantitated by obtaining the value for a region of interest (ROI) of the right optic nerve and the left optic nerve. The effect of H2O2 detoxification by catalase was evaluated by differences in the intensity of Gd-DTPA enhancement and T2 weighted signal in the ROI of the right and the left optic nerves at 7, 10, and 14 days after antigenic sensitization, from the pretreatment value obtained at day 3. The effectiveness of catalase detoxification of H2O2 was assessed with quantitative ultracytochemical localization of electron-dense, H2O2-derived cerium perhydroxide in the optic nerves. RESULTS: With PEG-catalase treatment, mean differences for Gd-DTPA enhancement in the ROI at 7, 10, and 14 days after antigenic sensitization were significantly reduced from the pretreatment values obtained 3 days after antigenic sensitization compared with the comparable interval values for untreated littermates. For T2 weighted signal intensity, only the 7- and 14-day values were significantly less with PEG-catalase compared with values for littermates obtained at comparable intervals. Quantitative ultracytochemical localization of H2O2-derived cerium perhydroxide reaction product revealed significant reductions in the medium number of cerium particle counts of the optic nerve head, sheath, and myelinated retrobulbar nerve. CONCLUSIONS: PEG-catalase reduced H2O2-derived cerium perhydroxide reaction product in the optic nerve but did not eliminate it, reversed disruption of the BBB as measured by Gd-DTPA enhancement, and reduced demyelination and edema as measured by T2 weighted signal intensity, suggesting detoxification of H2O2 as a new treatment strategy for disorders of primary demyelination of the central nervous system.

Animals↗

PubMed1994

Disruption of the blood-brain barrier in experimental optic neuritis: immunocytochemical co-localization of H2O2 and extravasated serum albumin.

PURPOSE: To probe the role of endogenous hydrogen peroxide (H2O2) in the pathogenesis of disruption of the blood-brain barrier (BBB) associated with experimental allergic encephalomyelitis (EAE), an animal model for primary central nervous system demyelination. METHODS: Strain-13 guinea pigs were sensitized for EAE with central myelin in complete Freund's adjuvant. Magnetic resonance imaging with Gd-DTPA was performed twice a week for 2 weeks to assess disruption of the BBB, in vivo, by the enhancement of the optic nerves. Two weeks after antigenic sensitization, ultracytochemical localization of endogenous H2O2 was performed using the cerium perhydroxide method, with co-localization of endogenous serum albumin extravasation using gold-labeled antibodies against serum albumin. Examination of blood vessels for perivascular immunogold-labeled serum albumin and H2O2 derived reaction product began in the optic nerve head and proceeded toward the retrobulbar optic nerve until a total of 20 vessels were evaluated per animal. RESULTS: Magnetic resonance imaging revealed Gd-DTPA enhancement of the optic nerves in all animals sensitized for EAE. Optic nerve ultrastructure revealed colloidal gold-labeled antibodies against serum albumin in the perivascular and adjacent interstitial spaces of capillaries and small venules in which H2O2 derived cerium perhydroxide reaction product was also simultaneously evident. Immunogold-labeled serum albumin was predominantly confined to the intravascular compartment of the optic nerve in the absence of perivascular H2O2 and/or perivascular foci of inflammatory cells. The difference between the mean percentage of blood vessels (61.8%) with co-localization of perivascular immunogold-labeled serum albumin and cerium perhydroxide reaction product, to the mean percentage of blood vessels (9.5%) with perivascular immunogold-labeled serum albumin in the absence of cerium perhydroxide, was statistically significant (P = 0.0019). CONCLUSIONS: Endogenous H2O2, found at the foci of BBB disruption, may be one of the mediators involved in the alteration of vascular permeability in experimental optic neuritis.

Animals↗

PubMed1993

Women with cerebral palsy: obstetric experience and neonatal outcome.

The aim of the study was to provide a preliminary basis for advising women with cerebral palsy (CP) who choose to initiate pregnancy regarding the course of parturition and the outcomes for their newborn infants. The authors studied 22 women with CP who had 38 pregnancies at a mean age of 26 years. Eight pregnancies were electively terminated and two resulted in miscarriage. Of the 28 viable pregnancies, one resulted in a preterm stillborn infant and two in preterm liveborn infants. Delivery was vaginal in 18 cases and by cesarean section in nine (one pregnancy was lost to follow-up). Pregnancy outcomes were reassuringly normal in this small, select sample of women with relatively mild CP. Possible effects of pregnancy and childbirth on general adaptive skills or specific child-care skills of women with CP could not be assessed in this retrospective study.

Abortion, Induced↗

PubMed1992

Intraorbital optic nerve and experimental optic neuritis. Correlation of fat suppression magnetic resonance imaging and electron microscopy.

To provide magnetic resonance imaging (MRI)-ultrastructural correlations of demyelinating lesions of the intraorbital optic nerve, the authors performed gadolinium-enhanced/T2-weighted fat-suppressed MRI and transmission electron microscopy of the optic nerves of animals with experimental allergic encephalomyelitis. Gadolinium enhancement of the optic nerve adjacent to the globe was seen on fat-suppressed T1-weighted MRI as early as 3 days after antigenic sensitization, increased in severity involving longer segments of nerve at 10 to 14 days, and persisted at 30 days. Gadolinium enhancement preceded T2-weighted signal aberrations. Ultrastructural evaluation of the intraorbital nerve revealed: (1) expansion of the extracellular space and inflammatory infiltrate that correlated with the intensity of gadolinium enhancement; (2) the degree of demyelination correlated with T2-weighted signal aberrations; (3) as deduced from gadolinium enhancement and T2 signal aberrations, breakdown of the blood-brain barrier preceded widespread demyelination; (4) lesions appeared to start at the optic nerve insertion into the globe and then progress toward the orbital apex.

Adipose Tissue↗

PubMed1990

A continuously variable field of view surface coil.

A new type of surface coil is described which allows the user to continuously vary the size of the field of view. This utilizes a modified radiofrequency trombone for size adjustment that results in a stable frequency over a wide range of dimensions. Results show that the coil may be increased in area by as much as 60% while maintaining frequency stability to ca. 1 MHz at 63.5 MHz. Images of the human spine are presented to demonstrate the clinical utility of the new design.

Equipment Design↗

PubMed1990

Trisomy 13 in the fetus.

A significant number of fetuses with trisomy 13 are spontaneously or voluntarily lost before birth; however, very few such fetuses have been systemically autopsied. In the present study, ten trisomy 13 fetuses of 130-305 mm in crown-rump length, estimated gestational age from 108 days to 239 days, were examined following either karyotype or ultrasonographic diagnosis and voluntary termination. Mean maternal age was 35.1 years. The spectrum of anatomical features was similar to that observed in neonates or older infants with trisomy 13, namely, holoprosencephaly, cyclopia, microphthalmia, cleft palate and lip, cardiac defect, polydactyly, and cystic kidney. Kidney weights were significantly increased above normal in eight of nine fetuses. Histologically, the cortex of these kidneys showed increased mitotic activity and blastemic appearance, which extended deep into the medullary areas. The weights and histology of other organs were normal except for slight increases in spleen weight.

Body Weight↗

PubMed1990

Gadolinium-DTPA-enhanced magnetic resonance imaging in experimental optic neuritis.

Magnetic resonance imaging (MRI) with gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) was used to investigate disruption of the blood-optic nerve barrier associated with acute autoimmune demyelination. Leakage of Gd-DTPA was seen in the optic nerves and optic chiasm of adult guinea pigs sensitized for acute experimental allergic encephalomyelitis, but not in normal unsensitized animals. This finding occurred as early as 5 to 8 days after antigenic sensitization with the myelin emulsion and before the onset of paralysis or ataxia. Pathologic examination at this early stage of experimental allergic encephalomyelitis showed an absence of demyelination in the optic nerves and optic chiasm, although scant perivascular foci of inflammatory cells were seen. Leakage of Gd-DTPA in the optic nerve before demyelination of this white matter tract illustrates that increased permeability of the blood-optic nerve barrier is an early, if not the initial, event in autoimmune demyelination, and the optic nerve is a common site of central nervous system involvement during the initial phase of acute experimental allergic encephalomyelitis. Findings in this animal model appear comparable with the results of MRI with Gd-DTPA in patients with optic neuritis, and they suggest that disruption of the blood-optic nerve barrier is a common denominator for both disorders of primary demyelination.

Animals↗

PubMed1990

Cocaine and pregnancy: a challenge for health care providers.

There is an alarming increase in the number of individuals using cocaine in this country. As many as 10 percent of all pregnant women have used cocaine one or more times during their pregnancy. The rising number of pregnant cocaine abusers who present themselves for medical services is creating a challenge for health care practitioners. This article addresses the biopsychosocial issues of cocaine abuse during pregnancy, including the medical impact of cocaine abuse on pregnant women and their newborn infants, behavioral manifestations of cocaine abusers that create health care management problems, and social work's contribution to the health care management of these women.

Adolescent↗

PubMed1990

Size of the fetal adrenal in bilateral renal agenesis.

Bilateral renal agenesis is a fetal malformation incompatible with extrauterine life. Accurate prenatal diagnosis is essential for patient counseling. False-negative diagnoses have been reported and were attributed to the sonographic misidentification of apparently hypertrophied fetal adrenal glands as fetal kidneys. To study the relationship between renal agenesis and adrenal size, we reviewed autopsy records from 11 affected fetuses that had undergone careful autopsy and organ weight determination in our laboratory. Anomalies of distant structures were present in five affected fetuses. A sonographic diagnosis of adrenal hypertrophy had been made in two cases. In four of 11 fetuses, the glands had taken on a flattened discoid appearance. The autopsy records of 240 normal fetuses were similarly reviewed, and regression lines were generated for adrenal weight based on foot length and crown-rump length. The adrenal weights from affected fetuses were well within normal limits when compared with these normal regression lines and with organ weight standards from the literature. We conclude that adrenal hypertrophy is not a common finding in this syndrome and that the reported false-negative diagnoses are more likely attributable to a change in adrenal shape rather than a true increase in adrenal mass.

Abnormalities, Multiple↗

PubMed1989

Congenital defect rates among spontaneous abortuses: twenty years of monitoring.

A 20-year study of 1,124 spontaneously aborted embryos and fetuses found 214 (19.0%) to have a localized defect or identifiable syndrome. No clear trend of change over time was noted. The rate is compared with other studies of spontaneously aborted specimens and is approximately ten times higher than in newborns. Forty (3.6%) had neural tube defects and 30 (2.7%) had a clinically recognized chromosomal phenotype. Fifteen had Turner's phenotype, four trisomy 18, and 11 triploidy. Amniotic bands occurred in eight. Two had bilateral renal agenesis. Thirty had some form of facial cleft.

Abortion, Spontaneous↗

PubMed1989

Congenital heart disease among spontaneous abortuses and stillborn fetuses: prevalence and associations.

The prevalence, range, and associations of congenital heart disease (CHD) were studied among 400 spontaneous abortuses between 9 and 40 weeks' gestation. Fifty-two (13.0%) cases of CHD were detected. To minimize selection bias the specimens were grouped by external appearance and the prevalence expressed accordingly. CHD was detected in 21 (7.3%) of 289 externally normal and 31 (27.9%) of 111 externally abnormal fetuses. Ventricular septal defect (VSD) was the most frequent CHD found in isolation as well as in combination with extracardiac malformations. Seventy-five percent of isolated CHD was VSD. Forty (69.2%) of the 52 cases of CHD were associated with extracardiac malformations. Chromosomal syndromes were responsible for a minimum of 19.2% of the cases and suspected in up to 36.5%. The most frequent associations involved the musculoskeletal system, central nervous system, abdominal wall, and kidneys. In contrast, studies of liveborn infants have reported 70% of CHD as isolated defects, including many CHD infrequently seen among spontaneous abortuses. This suggests that fetuses with isolated CHD often survive to term, and CHD does not significantly affect the survival of the fetus in utero. Ventricular septum formation may be particularly susceptible to hemodynamic changes and may be indicative of an underlying pathologic condition that also leads to a spontaneous abortion.

Abnormalities, Multiple↗