Biomedical subjects
Publications and source records attributed to J Long.
Kawasaki disease (mucocutaneous lymph node syndrome) typically presents with fever, rash, lymphadenitis, and mucositis. The colon is rarely involved and, to date, colitis has not been described as the presenting symptom. We report the imaging findings of a child with Kawasaki disease who presented with fever and focal left colitis.
OBJECTIVE: To quantify the risk of axillary nodal metastases due to delayed treatment of breast cancer during pregnancy. METHODS: A mathematical model using recently published data was developed to correlate primary breast tumor size with the percentage of pathologically positive axillary lymph nodes. Using this relationship obtained from pathologic data and the accepted relationship of tumor growth and time, Y2 = Y1e(In2)n/DT, an equation estimating the increased risk of axillary metastases due to each day of treatment delay was derived: delta X = 3.7 n/DT, where X = percent positive axillary lymph nodes, n = number of days delay in treatment, and DT = tumor doubling time. RESULTS: A 1-month delay in treatment for an early-stage primary breast cancer with a 130-day doubling time increases the risk of axillary lymph node involvement by 0.9%. A 3-month delay increases the risk by 2.6%, and a 6-month delay by 5.1%. For breast cancer with a 65-day doubling time, a 1-month delay increases the risk by 1.8%, a 3-month delay by 5.2%, and a 6-month delay by 10.2%. CONCLUSION: Axillary lymph nodes are the most important prognostic indicator for survival in breast cancer. Our mathematical model suggests the daily increased risk of axillary metastases due to treatment delay is 0.028% for tumors with moderate doubling times of 130 days and 0.057% for tumors with rapid doubling times of 65 days. This minimal maternal risk may be acceptable to some third-trimester pregnant women with early breast cancer, who prefer organ-sparing treatment with radiation after delivery to a mastectomy during pregnancy. This model further quantitates the increased risk of mortality borne by pregnant women whose breast cancer diagnosis is delayed.
STUDY OBJECTIVE: To measure serum CK-MB, a market of myocardial infarction (MI), in elderly men before and after cryoprostatectomy. DESIGN: Serum CK-MB was measured on each patient before and after cryoprostatectomy. Each patient's preoperative result was used as control measurement for comparison with measurements made after cryoprostatectomy. SETTING: Inpatient operating room and postanesthetic recovery unit of a university-affiliated general hospital. PATIENTS: 38 male patients, mean (SEM) age 69.1 +/- 1.4 years, undergoing cryoprostatectomy. INTERVENTIONS: All patients had a 12-lead ECG prior to surgery, in the recovery room, and 24 hours after surgery. Serum CK-MB was measured prior to induction of anesthesia, on arrival in the recovery room, and at 8 and 24 hours after surgery. Lactate dehydrogenase (LDH) and isoenzymes also were measured in 10 patients before and after cryoprostatectomy. MEASUREMENTS AND MAIN RESULTS: All patients underwent uneventful cryoprostatectomy. No patients had new ECG changes after surgery. All patients had normal serum CK and CK-MB concentrations before surgery. Serum CK and CK-MB were significantly elevated after cryoprostatectomy (p < 0.001). Enzyme values were greatest 8 hours after surgery: total CK mean 1453 +/- 145 U/L (range 199 to 3,356 U/L); CK-MB mean 52 +/- 3 ng/ml (range 12 to 114 ng/ml) or 5.0 +/- 0.5% of total CK (range 1.6% to 12.4%). All patients had significant elevations of LDH after cryoprostatectomy but did not show an increase in the ratio of LDH1 to LDH2 isoenzymes. Finally, unlike patients with an acute MI, the activity of CK-MB isoenzyme when measured by gel electrophoresis was two to three times greater (mean, 2.6 +/- 0.7) than the concentration measured with the monoclonal antibody assay in patients after cryoprostatectomy. CONCLUSION: Serum CK-MB is an unreliable test to diagnose an MI in patients who have undergone cryoprostatectomy.
The functions of fish skin during swimming remain enigmatic. Does skin stiffen the body and alter the propagation of the axial undulatory wave? To address this question, we measured the skin's in situ flexural stiffness and in vivo mechanical role in the longnose gar Lepisosteus osseus. To measure flexural stiffness, dead gar were gripped and bent in a device that measured applied bending moment (N m) and the resulting midline curvature (m-1). From these values, the flexural stiffness of the body (EI in N m2) was calculated before and after sequential alterations of skin structure. Cutting of the dermis between two caudal scale rows significantly reduced the flexural stiffness of the body and increased the neutral zone of curvature, a region of bending without detectable stiffness. Neither bending property was significantly altered by the removal of a caudal scale row. These alterations in skin structure were also made in live gar and the kinematics of steady swimming was measured before and after each treatment. Cutting of the dermis between two caudal scale rows, performed under anesthesia, changed the swimming kinematics of the fish: tailbeat frequency (Hz) and propulsive wave speed (body lengths per second, L s-1) decreased, while the depth (in L) of the trailing edge of the tail increased. The decreases in tailbeat frequency and wave speed are consistent with predictions of the theory of forced, harmonic vibrations; wave speed, if equated with resonance frequency, is proportional to the square root of a structure's stiffness. While it did not significantly reduce the body's flexural stiffness, surgical removal of a caudal scale row resulted in increased tailbeat amplitude and the relative total hydrodynamic power. In an attempt to understand the specific function of the scale row, we propose a model in which a scale row resists medio-lateral force applied by a single myomere, thus functioning to enhance mechanical advantage for bending. Finally, surgical removal of a precaudal scale row did not significantly alter any of the kinematic variables. This lack of effect is associated with a lower midline curvature of the precaudal region during swimming compared with that of the caudal region. Overall, these results demonstrate a causal relationship between skin, the passive flexural stiffness it imparts to the body and the influence of body stiffness on the undulatory wave speed and cycle frequency at which gar choose to swim.
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Clinically available blood pumps and those under development suffer from poor mechanical reliability and poor biocompatibility related to anatomic fit, hemolysis, and thrombosis. To alleviate these problems concurrently in a long-term device is a substantial challenge. Based on testing the performance of a prototype, and on our judgment of desired characteristics, we have configured an innovative ventricular assist device, the CFVAD4, for long-term use. The design process and its outcome, the CFVAD4 system configuration, is described. To provide unprecedented reliability and biocompatibility, magnetic bearings completely suspend the rotating pump impeller. The CFVAD4 uses a combination of passive (permanent) and active (electric) magnetic bearings, a mixed flow impeller, and a slotless 3-phase brushless DC motor. These components are shaped, oriented, and integrated to provide a compact, implantable, pancake-shaped unit for placement in the left upper abdominal quadrant of adult humans.
Demographic and outcome variables of children seen in a community hospital Level II pediatric trauma center are described and patterns of injury classified according to different mechanisms. Records were reviewed retrospectively of 184 patients seen over a one year period, 63% were male and the peak age group was 13-15 years (31%). Descriptive and nonparametric statistics were used to analyze the data. Mechanisms of injury included pedestrian vs auto (27%), falls (23%), motor vehicle occupants (18%), bicycle vs auto (17%), sports injuries (3%), motorcycle crashes (2%), gunshot wounds (2%), and stabbings (2%). Penetrating injuries had higher average trauma scores but blunt injuries were associated with higher mortality. Demographics and mechanisms of injury were similar to national studies. Emphasis on the use of pediatric trauma scores by emergency medical personnel is suggested to decrease the over-triage rate. The frequency of bicycle injuries and lack of helmet use prompted a major helmet promotion campaign.
OBJECTIVE: The aim of this study was to evaluate the hypothesis that prenatal cocaine exposure would negatively affect newborn behavior. METHODS: A prospective observational study of term infants recruited from the low-risk nursery used a structured, standardized interview to obtain maternal data. Cocaine exposure was determined by radioimmunoassay of the infant's meconium stool. An examiner blinded to the infant's cocaine status administered the Brazelton Neonatal Behavioral Assessment Scales. RESULTS: The sample was composed of 23 exposed and 29 nonexposed infants. On six of the seven Brazelton Neonatal Behavioral Assessment Scale clusters, cocaine-exposed infants performed less well than control infants, with significant differences observed for autonomic stability. In addition, a dose-response relationship was suggested. Significant negative, within-group relationships were evident in the exposed group, indicating poorer performance with increasing meconium cocaine concentration for orientation (r = -.40) and regulation of state (r = -.40). Regression model testing of the influence of meconium cocaine concentration on neurobehavioral outcomes, after controlling for significant confounders, identified a significant independent, negative effect of meconium cocaine concentration on two clusters-motor and regulation of state. CONCLUSION: In otherwise healthy full-term infants, prenatal cocaine exposure identified by quantitative analysis of cocaine concentration in meconium had a significant, independent negative association with motor and regulation of state that remained after controlling for other significant confounders. A dose-response relationship was evident.
The maize homebox gene knotted1 (kn1) is expressed in vegetative and floral meristems and is down-regulated at the site of primordia formation. kn1-related genes from maize and other species also show meristem-specific expression and offer additional tools for studying the activities of shoot meristems. Members of this gene family are expressed early in embryogenesis, providing molecular markers for meristem initiation. Ectopic expression of either kn1 or a related Arabidopsis gene, KNAT1, causes dramatic alterations in Arabidopsis and tobacco leaf morphology. Most significantly, meristems form on the leaf, producing small shoots. We discuss whether the phenotypes can be interpreted as changes in positional information or timing of determination.
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OBJECTIVES: In view of the segmental occurrence of coronary atherosclerosis, we postulated that acetylcholine may cause heterogeneous vasomotion, depending on the extent of vessel analyzed, criteria for change in vessel caliber and dose of drug administered. BACKGROUND: Previous studies have reported that acetylcholine causes constriction of atherosclerotic arteries. This dysfunction of endothelium-dependent dilation may be seen without angiographically detectable disease. METHODS: We developed algorithms to quantitate the dimensions of a single coronary artery over virtually its entire length during a control state and during graded doses of intracoronary acetylcholine. On the basis of triplicate control angiograms, the limit of detection of a change from control diameter was 0.31 mm (> or = 2 SD). RESULTS: Analysis of multiple segments (each 5.6 +/- 1.1 [mean +/- SD] mm) along a single coronary artery revealed a heterogeneous response to acetylcholine in 27 of 31 patients at the 10(-4) mol/liter dose and in 29 of 31 patients when responses at 10(-6), 10(-5) and 10(-4) mol/liter doses were combined; in this latter analysis, constriction and dilation in the same vessel occurred in 45% of the patients. With acetylcholine, most of 349 segments demonstrated no change, but the greatest frequency of vasoconstriction (24.6%) and vasodilation (6.9%) was seen at the 10(-4) mol/liter dose. Inducible vasomotion was observed as far distally as 7.3 cm from the site of acetylcholine infusion. CONCLUSIONS: Response to intracoronary acetylcholine with mild coronary disease is heterogeneous; disparate dimensional responses may occur in different segments of the same vessel. Inclusion of all analyzable regions of a coronary artery and the use of a reproducibility limit for quantitative angiography are optimal for assessment of segmental coronary vasomotion.
OBJECTIVE: To determine whether methotrexate (MTX) therapy for 24 months prevents progression of radiographic damage in psoriatic arthritis (PsA). METHODS: Patients who were given MTX during their attendance at the psoriatic arthritis clinic were enrolled in the study. Patients who had never had MTX and who were matched by damage, actively inflamed joints, sex, and disease duration were identified from the PsA database as controls. The outcome measure was increase in the number of damaged joints. RESULTS: The study population comprised 38 patients (16 F, 22 M) with a mean age of 44.6 years and disease duration of 11.4 years. Twenty-three patients continued therapy for 24 months. Clinical evaluation revealed that 45% of the patients had > or = 40% improvement in actively inflamed joint count at 6 and 24 months. Radiographs were available for 19 of the 23 patients who took MTX for 24 months, and they were compared to their respective controls. Radiographic damage scores at 24 months showed an increase in the damage score in 63% of the patients. Compared to the matched controls, there was no statistically significant difference in the progression in damage. CONCLUSION: Our results suggest that compared to other regimens, MTX conferred no advantage with respect to clinical response or longterm damage even after 24 months of therapy.
The aim of this investigation has been to assess whether gold therapy prevents radiologic progression of psoriatic arthritis (PsA) over a period of 2 y. Eighteen patients (11 males, 7 females, mean age 42 y, DD 6.5 y) who were initiated on intramuscular gold during their attendance at the Psoriatic Arthritis Clinic were studied. For each gold-treated patient, 2 matched control patients, who had never had gold therapy, were identified from the PsA database. The control patients were similar to the patient population in gender, age, disease duration, number of actively inflamed joints, radiologic score and other medications used, and were followed in the clinic for at least 24 months. Actively-inflamed joint count decreased by > or = 40% in 9 of 18 gold-treated patients at 12 months. Seven patients continued gold for 24 months, while 11 discontinued gold for either lack of efficacy (4) or side effects (7). A comparison of the change in radiographic evidence of damage in the peripheral joints between the 18 gold-treated patients and the 36 controls revealed that there was no statistical difference in disease progression. These results suggest that gold therapy does not prevent the progression of damage in patients with psoriatic arthritis.
The von Hippel-Lindau syndrome is the most well known cause of familial renal cancer. Because affected individuals with renal lesions can have complex, multisystem manifestations of von Hippel-Lindau disease, our renal management strategy has included parenchymal sparing surgery whenever possible. From May 1988 to January 1993, 20 patients with hereditary renal cell carcinoma (19 with von Hippel-Lindau disease and 1 with hereditary papillary renal cancer) underwent renal exploration with the intent of performing parenchymal sparing surgery. A total of 7 nephrectomies and 27 parenchymal sparing procedures was performed. Additional procedures performed included 2 bilateral adrenalectomies for pheochromocytomas, 1 resection of a renal vein thrombus and 1 resection of a pancreatic islet cell tumor. Renal atrophy occurred in 3 of 27 kidneys (11%) treated by parenchymal sparing surgery. In 8 kidneys of 7 patients new solid lesions developed and in 14 kidneys of 12 patients no new solid lesions developed during a mean followup of 26 months (range 6 to 60 months). The use of parenchymal sparing surgery in patients with familial forms of kidney cancer is based on a desire to maintain renal function as long as possible while reducing the risk of metastases. The potential advantages and disadvantages of more ablative surgical treatment requiring subsequent dialysis or transplantation in patients with existing or potential central nervous system, eye, pancreas and/or adrenal tumors must be weighed against the possibility of renal cancer metastases or recurrence when deciding on the use of parenchymal sparing surgery.
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The homeobox gene knotted1 (kn1) was first isolated by transposon tagging a dominant leaf mutant in maize. Related maize genes, isolated by virtue of sequence conservation within the homeobox, fall into two classes based on sequence similarity and expression patterns. Here, we report the characterization of two genes, KNAT1 and KNAT2 (for knotted-like from Arabidopsis thaliana) that were cloned from Arabidopsis using the kn1 homeobox as a heterologous probe. The homeodomains of KNAT1 and KNAT2 are very similar to the homeodomains of proteins encoded by class 1 maize genes, ranging from 78 to 95% amino acid identity. Overall, the deduced KNAT1 and KNAT2 proteins share amino acid identities of 53 and 40%, respectively, with the KN1 protein. Intron positions are also fairly well conserved among KNAT1, KNAT2, and kn1. Based on in situ hybridization analysis, the expression pattern of KNAT1 during vegetative development is similar to that of class 1 maize genes. In the shoot apex, KNAT1 transcript is localized primarily to the shoot apical meristem; down-regulation of expression occurs as leaf primordia are initiated. In contrast to the expression of class 1 maize genes in floral and inflorescence meristems, the expression of KNAT1 in the shoot meristem decreases during the floral transition and is restricted to the cortex of the inflorescence stem. Transgenic Arabidopsis plants carrying the KNAT1 cDNA and the kn1 cDNA fused to the cauliflower mosaic virus 35S promoter were generated. Misexpression of KNAT1 and kn1 resulted in highly abnormal leaf morphology that included severely lobed leaves. The expression pattern of KNAT1 in the shoot meristem combined with the results of transgenic overexpression experiments supports the hypothesis that class 1 kn1-like genes play a role in morphogenesis.