Search PubMed⌕ Search

Biomedical subjects

J T Davis

Publications and source records attributed to J T Davis.

At least 37 records · Page 2Linked to original sources

Cellular retinoic acid-binding protein(II) presence in rat uterine epithelial cells correlates with their synthesis of retinoic acid.

Vitamin A (retinol) and retinoic acid are necessary for the maintenance of the female reproductive system of higher animals. Our previous work has demonstrated cell specific expression of cellular retinoic acid-binding protein (CRABP) and cellular retinoic-acid binding protein(II) [CRABP(II)] in the uterus of the rat. CRABP(II) expression was shown to be induced in the uterine surface epithelial cells by treatment of prepubertal rats with pregnant mare serum gonadotropin (PMSG). Here we report that, after PMSG treatment, collected uteri had markedly higher levels of retinoic acid than did the uteri of prepubertal rats treated with the control vehicle. Smooth muscle, stromal, and epithelial cells were then cultured from uteri from such animals and provided with retinol or with the retinol/retinol-binding protein complex. Retinoic acid production, analyzed by high-performance liquid chromatography, was observed for the epithelial cells from the uteri of prepubertal animals treated with PMSG, cells previously shown to express CRABP(II) and confirmed here to continue to express it in culture. Little or no retinoic acid was produced by cultured epithelial cells from the prepubertal uteri [shown previously to be negative for CRABP(II)] or by smooth muscle and stromal cells taken from uteri of prepubertal or PMSG-treated rats (shown previously to express CRABP). Retinoic acid production by uterine epithelial cells [and CRABP(II) expression] was also observed if the prepubertal rat was treated with estrogen before cell collection. At no time did cells expressing CRABP exhibit significant retinoic acid synthesis. Thus, this system revealed an important difference in retinoid metabolism between cells expressing CRABP and CRABP(II) and suggests CRABP(II) may participate in retinoic acid production and/or secretion.

Animals↗

Population requirements for capitation planning in pediatric cardiac surgery.

OBJECTIVE: To determine the population number necessary to generate a sufficient volume of pediatric cardiac surgeries to allow accurate prediction of resource utilization. DESIGN: All pediatric cardiac surgical patients receive care in our institution by means of only four clinical pathways that are based on acuity, not diagnosis or procedure. This allows accurate tracking of resource utilization. Based on available information, 750 consecutive surgically treated patients were retrospectively assigned to a pathway. They were subsequently subdivided into study groups of decreasing sizes from 150 to 35. Variability of pathway distribution from group to group was examined as a measure of the ability to predict resource utilization based on group size. Pediatric cardiac statistics from the state of Ohio were then used to extrapolate to the population base necessary to generate each group size. SETTING: A regional pediatric cardiac referral center. PATIENTS: All sequential patients who underwent pediatric cardiac surgery between July 1991 and January 1994. RESULTS: Statewide statistics showed that a population base of 1 million people generates 100 pediatric cardiac operations. Groups of 100 patients or greater had minimal variation in pathway distribution from group to group, allowing accurate prediction of hospital charges. This was not true for groups of 50 patients or less. CONCLUSIONS: Resource utilization for pediatric cardiac surgery can be accurately predicted in a capitated setting for populations of 1 million covered lives (100 procedures) or greater. For populations of 500 000 covered lives or less, variability of case mix is great enough to suggest the need for a more individualized payment mechanism.

Capitation Fee↗

Anomalous course of the left main coronary artery in tetralogy of Fallot.

An extremely rare coronary artery anomaly where the left main coronary artery arose anteriorly from the right coronary sinus and coursed in front of the right ventricular outflow tract was present in a patient with tetralogy of Fallot. Preoperative angiocardiography was interpreted as normal. Operative recognition was prevented by dense adhesions and a partial intramural course. Division of the vessel at repair resulted in death of the patient. The angiographic pattern associated with this anomaly is very unusual, and in many views looks deceptively normal. Details are presented.

Coronary Angiography↗

Intrathoracic cystic hygroma: a report of three cases.

Cystic hygromas are relatively uncommon benign tumors of the lymphatic system. The lesions frequently are apparent at birth, and more than 90% are detected before the end of the second year of life. Most commonly, cystic hygroma presents as a soft tissue mass in the posterior triangle of the neck, and only rarely does it extend into the mediastinum. Isolated intrathoracic hygromas are exceedingly rare and have been reported infrequently among children. Herein the authors review three cases of intrathoracic cystic hygroma, spanning a period of 30 years at their institution.

Child, Preschool↗

Transfusion patterns in pediatric open heart surgery.

BACKGROUND: Transfusions in pediatric open heart surgery were analyzed to determine the percentage of patients transfused, the types and volumes of blood components used, and the relationships among transfusions, patient characteristics, surgeon, and surgical procedure. STUDY DESIGN AND METHODS: In a 9-month period, 122 patients, aged 12 or less (median, 1 year; 31% <4 months old), underwent 126 procedures (37 routine, 60 complex, 29 repeat operations). Bypass circuit size and priming solution, target intraoperative hematocrit, heparinization, protamine reversal, and transfusion indications and doses were standardized. The number of full "adult" units of packed red cells (RBCs), units of fresh-frozen plasma (FFP), and platelet concentrates (PCs) transfused in the operating room through postoperative Day 3 were tabulated. RESULTS: RBCs, FFPs, and PCs were transfused in 98, 54, and 58 percent of cases, respectively. Twenty-two percent of components were transfused postoperatively. The average numbers of components transfused for complex procedures (3.4 RBCs, 6.1 total) and repeat operations (4.0 RBCs, 8.1 total) were greater than those for routine procedures (1.8 RBCs, 2.1 total) (p<0.01). The average total number of components transfused did not correlate with surgeon or patient age; patients <4 months old used the largest mean numbers of RBCs and total components of all types. For four procedures, preoperative crossmatch and directed-donation collection orders that would be expected to produce acceptable utilization rates and a <15-percent chance of needing additional components were determined. CONCLUSION: Blood order protocols for pediatric open heart surgery can be procedure-specific, should address the use of non-red cell components, and should cover early postoperative transfusions.

Blood Transfusion↗

Determination of duplex Doppler ultrasound criteria appropriate to the North American Symptomatic Carotid Endarterectomy Trial.

BACKGROUND AND PURPOSE: The North American Symptomatic Carotid Endarterectomy Trail (NASCET) demonstrated the benefit of carotid endarterectomy for symptomatic patients with > or = 70% carotid stenosis. Screening for detection of significant carotid occlusive disease has relied on duplex Doppler imaging. However, traditional duplex categories (50% to 79%, 80% to 99%) are not directly applicable to NASCET. We sought to evaluate duplex criteria for determination of > or = 70% carotid stenosis. METHODS: Duplex scan and arteriograms of 110 patients (210 carotids), performed within 1 month of each other, were reviewed by blinded readers. Arteriographic stenosis was determined by the NASCET method. Duplex measurements of peak systolic and end-diastolic velocity (PSV, EDV) were recorded, and ratios of velocities in the internal and common carotid arteries (ICA, CCA) were calculated. Receiver-operator characteristic (ROC) curves of sensitivity, specificity, positive and negative predictive values (PPV, NPV), and accuracy were determined. RESULTS: Interobserver agreement for measurement of arteriographic stenosis was "almost perfect" (kappa=0.86). The criteria chosen for detection of > or = 70% stenosis were PSVICA>210 cm/s (sensitivity, 94%; specificity, 77%; PPV, 68% NPV, 96% accuracy, 83%) EDVICA>70 cm/s (sensitivity, 92%; specificity, 60%; PPV, 73%; NPV, 86%; accuracy 77%), PSVica/PSVCCA >3.0 (sensitivity, 91%; specificity, 78%; PPV, 70%; NPV, 94%; accuracy, 83%), and EDVICA/EDVCCA>3.3 (sensitivity, 100%; specificity, 65%; PPV, 65% NPV, 100%; accuracy, 79%). CONCLUSIONS: We conclude that > or = 70% carotid stenosis can be reliably determined by duplex Doppler ultrasound. Individual vascular laboratories must validate their own results.

Carotid Artery, Common↗

Regulation and localization of cellular retinol-binding protein, retinol-binding protein, cellular retinoic acid-binding protein (CRABP), and CRABP II in the uterus of the pseudopregnant rat.

Three members of the superfamily of small intracellular carrier proteins for lipophilic compounds are cellular retinol-binding protein (CRBP), cellular retinoic acid-binding protein (CRABP), and cellular retinoic acid-binding protein II (CRABP II). Retinol-binding protein (RBP) is a secreted protein that binds and solubilizes vitamin A for transport. Here we report the coordinate regulation of RBP, CRBP, retinol, and CRABP II in the uterus of the pseudopregnant rat. In the proliferative stage of the uterus, which was induced by PMSG, the messenger RNA (mRNA) and protein levels of RBP and CRBP as well as retinol levels significantly decreased. This pattern of regulation was duplicated by estrogen treatment of prepubertal rats. In addition, CRBP and RBP were found to be colocalized to the stromal cells of the rat uterus by immunohistochemistry and [35S]methionine-labeled affinity chromatography, respectively, and were not detected in other cell populations. CRABP II mRNA and protein expression were up-regulated in the proliferative phase of the uterus brought about by PMSG injection or, alternatively, by estrogen treatment of prepubertal rats. CRABP II was localized to the surface epithelium, but was not seen elsewhere, including glandular epithelium. Immunolocalization of CRABP showed staining of the smooth muscle and stromal cells of the uterus. The appearance of CRABP in the stroma of the uterus also correlated with PMSG injection as well as estrogen treatment. Although estrogen induced the appearance of both binding proteins, CRABP mRNA levels peaked between 4-24 h postestrogen treatment, whereas CRABP II mRNA levels continued to rise 48 h postestrogen treatment. These data demonstrate an important role for vitamin A and retinoid-binding proteins in rat uterine physiology.

Animals↗

Magnetoencephalographic assessment of spontaneous brain activity in schizophrenia.

Magnetoencephalography (MEG) offers an attractive alternative to electroencephalography (EEG) in the assessment of psychiatric patients. In this study, a whole-head biomagnetometer equipped with 122 super-cooled sensors was used to assess spontaneous neuromagnetic activity in 11 unmedicated schizophrenic patients and 8 schizophrenic patients medicated for more than 8 weeks with novel antipsychotics (5 of whom were initially studied as part of the unmedicated group). Ten normal (nonpsychiatric) controls were also examined. For each subject, 5 minutes of data were collected in an eyes-closed state. Data were visually inspected for gross MEG abnormalities, and average power spectra were calculated for the data at each sensor. No gross abnormalities were identified for control subjects. One unmedicated schizophrenic patient showed epileptiform sharp waves, and 4 showed abnormal slow waves. No gross MEG abnormalities were found for the medicated schizophrenic group (which included 3 patients who had previously shown slow waves in the unmedicated state). Spectral analyses showed that the schizophrenia patients demonstrated lower alpha power and peak frequency than controls. The data are interpreted within the context of previously reported magnetic resonance abnormalities of the thalamus.

Adult↗

Hydrolysis of the GlcNAc oxazoline: deamidation and acyl rearrangement.

The specific deamidation of 2-acetamido-1,3,4,6-tetra-O-acetyl-alpha-D-glucopyranose is achieved by p-toluenesulfonic acid-promoted hydrolysis of 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-alpha-D-glucopyrano)-[2,1 -d]-2- oxazoline 2 to give quantitative formation of the 1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-alpha-D-glucopyranose p-toluenesulfonate (5d). This two-step procedure provides an amino sugar which may be readily acylated to give novel glycoconjugates. Alternatively, base-catalyzed O-1-->N-2 acyl rearrangement of the amino tosylate 5d gives the 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-D-glucopyranose 4 as a 9:1 mixture of alpha and beta anomers. Thus, hydrolysis of GlcNAc oxazoline 2 gives the amino-ester 5 as the kinetic product and the amido-alcohol 4 as the thermodynamic product.

Acylation↗

Hypoplasia of the eustachian valve and abnormal orientation of the limbus of the foramen ovale in hypoplastic left heart syndrome.

We examined the eustachian valve and the limbus of the foramen ovale in 42 hearts with hypoplastic left heart syndrome (HLHS) and in 16 normal hearts. In HLHS, only 4.8% of the eustachian valves were moderately to well developed, whereas the remaining 95.2% were abnormal (p < 0.001): 92.9% of the eustachian valves were absent or markedly hypoplastic, and 2.4% had an abnormally redundant and enlarged eustachian valve. The eustachian valve was well developed in 87.5% of normal hearts. In addition, the lesser development of the eustachian valve seemed to correlate with lesser development of the left side of the heart. The limbus was well developed in 100% of the normal hearts and moderately to well developed in only 33.3% of the HLHS group (p < 0.001). Most hearts in the HLHS group had marked hypoplasia of the limbus, which was rotated and deviated so as to be close to the superior vena caval entrance.

Aortic Valve↗

Clinical pathways can be based on acuity, not diagnosis.

The standardization of medical practice is gaining acceptance as a technique for controlling length of stay and hospital charges, while maintaining quality. Most clinical pathways address specific diagnoses or procedures, but we have developed a new approach in which pathways for cardiac care are based on acuity. All congenital cardiac surgical care rendered at Columbus Children's Hospital now falls within one of four such clinical pathways. This simplified approach is easy to use and has been well accepted. Our experience in a group of 107 consecutive patients treated in this fashion is described. The results of variance analyses, along with length of stay and charge data, are presented to demonstrate the degree to which resource utilization can be standardized in this widely variable group of patients whose problems were made cohesive by classification according to acuity level. We conclude that the resultant standardization offers considerable advantages for the managed care environment.

Cardiac Surgical Procedures↗

Lateral thoracic expansion for Jeune's asphyxiating dystrophy: a new approach.

A new procedure is described for thoracic expansion in Jeune's asphyxiating dystrophy. The chest wall is enlarged by division of ribs and underlying tissue in a staggered fashion so that either rib or periosteum covers the lung. New bone formation has been demonstrated so that a viable enlargement has been obtained. The clinical result is excellent to date.

Asphyxia Neonatorum↗

Inhibition of crossed caudal interneurons by lateral interneurons in lamprey spinal chord during fictive locomotion.

Templates of the membrane potential profiles from lateral (LI) interneurons and motoneurons during glutamate- and N-methyl-D-aspartate (NMDA)-induced fictive locomotion showed pronounced plateau phases. In contrast, crossed caudal (CC) interneurons had a less obvious and steeper plateau region that was followed by a clear notch coinciding with the end of the lateral interneuron plateau phase. These results indicate a significant inhibitory input from LI to CC interneurons.

Animals↗

Primary aortoesophageal fistula caused by an atherosclerotic thoracoabdominal aortic aneurysm: a case report and review of the literature.

A 55-year-old woman suffered an episode of massive hematemesis caused by an aortoesophageal fistula from an atherosclerotic thoracoabdominal aortic aneurysm. In situ grafting of the thoracic portion of the aneurysm was followed by sepsis and a sinus tract between the mid-esophagus and the aortic prosthesis. Graft removal, aortic closure, esophageal closure and axillobifemoral bypass allowed clearing of the sepsis and recovery. Severe hypertension followed aortic closure and extra-anatomic bypass and resulted in the eventual death of the patient 16 months later from dissection of the ascending aorta with pericardial tamponade. There are very few treated cases of aortoesophageal fistulas caused by atherosclerotic aneurysms reported in the literature. Furthermore, there are no reported cases where the aorta was closed at the level of the subclavian artery with extra-anatomic bypass to restore blood flow to the lower half of the body.

Aortic Aneurysm↗

Determination of sixty percent or greater carotid artery stenosis by duplex Doppler ultrasonography.

PURPOSE: The Asymptomatic Carotid Atherosclerosis Study, demonstrating the benefit of carotid endarterectomy for symptom-free patients with 60% or greater carotid artery stenosis, has given rise to the need for development of screening parameters for detection of these lesions. Traditional duplex categories (50% to 79%, 80% to 99%) are not applicable. We sought to develop duplex criteria for determination of 60% or greater carotid artery stenosis by comparison with arteriography. METHODS: The duplex scans and arteriograms of 110 patients (210 carotid arteries), obtained within 1 month of each other, were reviewed by blinded readers. Arteriographic stenosis was determined by the method of the Asymptomatic Carotid Atherosclerosis Study. Duplex measurements of peak systolic velocity (PSV) and end-diastolic velocity (EDV) were recorded, and ratios of velocities in the internal and common carotid arteries (ICA, CCA) were calculated. Sensitivity, specificity, positive and negative predictive values (PPV, NPV), and accuracy were determined, and receiver-operator characteristic curves were generated. RESULTS: Interobserver agreement for measurement of arteriographic stenosis was "almost perfect" (kappa = 0.86). The criteria determined for detection of 60% or greater stenosis were as follows: PSVICA > 170 cm/sec (sensitivity 98%, specificity 87%, PPV 88%, NPV 98%, accuracy 92%), EDVICA > 40 cm/sec (sensitivity 97%, specificity 52%, PPV 86%, NPV 86%, accuracy 86%), PSVICA/PSVCCA > 2.0 (sensitivity 97%, specificity 73%, PPV 78%, NPV 96%, accuracy 76%), EDVICA/EDVCCA > 2.4 (sensitivity 100%, specificity 80%, PPV 88%, NPV 100%, accuracy 88%). If all of the above criteria were met, 100% accuracy was achieved. CONCLUSION: It is concluded that 60% or greater carotid artery stenosis can be reliably determined by duplex criteria. The use of receiver-operator characteristic curves allows the individualization of duplex criteria appropriate to specific clinical situations of patient screening for lesions (high sensitivity and NPV) or use as a sole preoperative imaging modality (high PPV). Individual vascular laboratories must validate their own results.

Blood Flow Velocity↗