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Biomedical subjects

R D Harris

Publications and source records attributed to R D Harris.

At least 73 records · Page 4Linked to original sources
PubMed1990

Expression, characterization, and purification of a phosphorylated rabies nucleoprotein synthesized in insect cells by baculovirus vectors.

A baculovirus expression vector (AcNPV3) derived from the nuclear polyhedrosis virus of Autographa californica (AcNPV) was prepared containing the complete coding region of the nucleoprotein (N) gene of rabies virus (Gif-sur-Yvette clone of the CVS strain). The gene was placed under the control of the AcNPV polyhedrin promoter and was expressed to high levels (66 mg N protein/liter of 2 x 10(9) cells) by the derived recombinant virus using a Spodoptera frugiperda cell line. Using available antisera, it was established that the antigenic characteristics of the N protein were similar by comparison with those of the native N protein of rabies virus. Characterization of the expressed protein established that, like the N protein of mammalian cell-grown CVS virus, the N protein was phosphorylated. The expressed rabies N protein induced antibodies in mice that reacted strongly with the rabies viral protein. The expressed nucleoprotein was recovered from the insect cells by differential centrifugation followed by ion exchange chromatography. The expressed rabies N protein represents a source of authentic protein suitable for virus diagnosis as well as structural studies.

Animals↗
PubMed1990

Unusual cause for recurrent Cushing syndrome and its diagnosis by computed tomography and NP-59 radiocholesterol scanning.

Cushing syndrome can recur following an adrenalectomy. One of the primary causes is recurrence of adrenal carcinoma either locally or from metastases. Hyperplasia and hyperfunction of adrenal remnants may also occur if there is pituitary stimulation. We have a patient in whom recurrent Cushing syndrome developed from small nonmalignant deposits of adrenal tissue in the perirenal adipose tissue following adrenalectomy of a benign adenoma. These deposits were identifiable by computed tomography. A false-negative NP-59 iodocholesterol scan was instructive in pointing out some problems in the interpretation of this type of scan for adrenal tissue.

Adenoma↗
PubMed1990

Placental hypoechoic-anechoic areas and infarction: sonographic-pathologic correlation.

High-resolution ultrasound (US) and pathologic analysis were used to define the relationship between placental hypoechoic-anechoic areas, frequently seen in the third trimester, and the clinically significant entity of placental infarction. Placentas were obtained from three groups of patients: those prospectively demonstrating one or more placental hypoechoic-anechoic areas greater than or equal to 1 cm in diameter on third-trimester sonograms (n = 14), those with risk factors for vascular disease (n = 12), and control patients without risk factors (n = 16). Pathologic analysis demonstrated significantly more infarcts in patients with risk factors than in control patients (17 vs three, P = .047). Of a total of 22 infarcts from all three groups, 19 (86%) were isoechoic to viable placenta and therefore not detected with US. The three infarcts identified with US contained hypoechoic or anechoic foci of fibrin or hemorrhage. Of 26 placental hypoechoic-anechoic areas 23 (88%) were decidual septal cysts or intervillous thrombosis without infarction. The authors conclude that nonhemorrhagic placental infarction cannot be identified with ex utero US and, by inference, that prenatal US is probably insensitive for detection of placental infarction.

Female↗
PubMed1989

MRI of splenic hemangioma associated with thrombocytopenia.

In contrast to the only previously published description, the magnetic resonance appearance of a splenic hemangioma was markedly heterogeneous on T2-weighted images due to extensive infarction and large vascular pools. Magnetic resonance images correlated precisely with the pathological findings. The hemangioma caused thrombocytopenia, a well-documented albeit rare hematologic phenomenon associated with visceral hemangioma.

Adult↗
PubMed1989

MR and CT imaging of perirenal amyloidosis.

The radiographic findings of perirenal amyloidosis have not previously been described. A patient with multiple myeloma and primary amyloidosis (AL) with secondary hydronephrosis as examined on plain film, retrograde ureteropyelography, computed tomography, and magnetic resonance imaging is presented. This case illustrates perirenal amyloidosis and demonstrates the utility of CT and MRI in patient management and surgical treatment.

Aged↗
PubMed1989

Offset electrocardiographic electrode simulating a pulmonary nodule on radiographs.

A recently developed type of electrocardiographic (ECG) monitoring electrode may simulate a pulmonary nodule on chest radiographs. The artifact results from the offset design of the electrode, which contrasts with the configuration of conventional electrodes. Awareness of this potential artifact is important to prevent misdiagnosis.

Diagnostic Errors↗
PubMed1989

An enzyme immunoassay for isotyping mouse monoclonal antibodies.

A rapid, simply performed and relatively inexpensive enzyme immunoassay for isotyping mouse monoclonal antibodies is described, based on the urease/urea system. Because of the high sensitivity (less than 0.1 microgram/ml of immunoglobulin can be detected in cell culture medium) no treatment of the hybridoma supernatant sample is required prior to assay, and the isotype of a mouse immunoglobulin can be determined in about thirty minutes.

Animals↗
PubMed1988

A method for fixation of elastin demonstrated by stress/strain characterization.

In the process of examining the effects of oxidants on the mechanical properties of purified ligamentum nuchae elastin, it was found that sodium hypochlorite as constituted in Clorox will fix elastin at any preset extension. The treatments were carried out at a 1 to 5 dilution and at 0, 20 and 40% extensions. In each case, the new resting length was near the preset length and the elastic modulus increased remarkably, for example, from 1 to 5 x 10(7) dynes/cm2 for the sample preset at 20% extension. As reflected in the increased elastic modulus, the fixation was achieved by the formation of irreversible cross-links. Due to the near absence of side chains containing chemically reactive groups suitable for contributing to the formation of additional cross-links required in fixation, this is the first method whereby irreversible fixation of elastin has been achieved. The absence of a suitable fixative for elastic tissues such as lung, arteries, etc. has limited the microscopic characterization of functional extended states of these tissues.

Animals↗
PubMed1988

Retroperitoneal leiomyosarcoma: a rare cause of adrenal pseudotumor on CT and MRI.

Numerous causes of adrenal pseudotumors have been previously described based on computed tomography findings, (CT) with normal anatomical structures being more common causes than extraadrenal neoplasms. This case describes a rare retroperitoneal tumor: a primary vascular leiomyosarcoma arising from the renal hilus, which mimicked an adrenal malignancy on CT and magnetic resonance imaging.

Adrenal Gland Neoplasms↗
PubMed1988

Mechanochemical coupling in synthetic polypeptides by modulation of an inverse temperature transition.

For the polypentapeptide of elastin, (L-Val-L-Pro-Gly-L-Val-Gly)n, and appropriate analogs when suitably cross-linked, it has been previously demonstrated that development of elastomeric force at fixed length and length changes at fixed load occur as the result of an inverse temperature transition, with the temperature of the transition being inversely dependent on the hydrophobicity of the polypeptide. This suggests that at fixed temperature a chemical means of reversibly changing the hydrophobicity could be used for mechanochemical coupling. Evidence for this mechanism of mechanochemical coupling is given here with a 4%-Glu-polypentapeptide, in which the valine in position 4 is replaced in 1 out of 5 pentamers by a glutamic acid residue. Before cross-linking, the temperature for aggregation of 4%-Glu-polypentapeptide is remarkably sensitive to pH, shifting from 25 degrees C at pH 2 to 70 degrees C at pH 7.4 in phosphate-buffered saline (PBS). At 37 degrees C, the cross-linked 4%-Glu-polypentapeptide matrix in PBS undergoes a pH-modulated contraction and relaxation with a change from pH 4.3 to 3.3 and back. The mean distance between carboxylates at pH 4.3 in the elastomeric matrix is greater than 40 A, twice the mean distance between negatively charged species in PBS. Accordingly, charge-charge repulsion is expected to make little or no contribution to the coupling. Mechanochemical coupling is demonstrated at fixed load by monitoring pH dependence of length and at constant length by monitoring pH dependence of force. To our knowledge, this is the first demonstration of mechanochemical coupling in a synthetic polypeptide and the first system to provide a test of the recent proposal that chemical modulation of an inverse temperature transition can be a mechanism for mechanochemical coupling. It is suggested that phosphorylation and dephosphorylation may modulate structure and forces in proteins by locally shifting the temperatures of inverse temperature transitions.

Amino Acid Sequence↗
PubMed1988

Yolk sac calcification: a sonographic finding associated with intrauterine embryonic demise in the first trimester.

Two cases of the sonographic demonstration of yolk sac calcification associated with first-trimester intrauterine embryonic demise are reported. Histologic verification was obtained in one case. Yolk sac calcification may reflect typical dystrophic changes or be more specifically related to a yolk sac calcium-binding protein. Awareness of this sonographic finding--which the authors believe to be previously undescribed--may prevent diagnostic errors.

Adolescent↗
PubMed1988

The prevalence and significance of missed scapular fractures in blunt chest trauma.

Recent concepts regarding surgical management of fractures of the glenoid and scapular neck provide a new imperative to their early recognition. The initial routine supine chest radiograph obtained in patients with major blunt chest trauma provides the earliest opportunity to identify scapular fractures. A retrospective analysis of 100 patients with major blunt chest trauma who were discharged with the diagnosis of scapular fracture was performed to determine (1) the frequency with which the diagnosis of scapular fracture was made on the initial chest radiograph and (2) the prevalence and type of regional injuries that could serve to identify which of these patients are most likely to have sustained scapular fracture(s). The scapular fracture was diagnosed on the initial chest radiograph in only 57 (57%) of 100 patients and, although present, was not recognized in 43 (43%) of 100. In the group in which the fractures were not recognized, the fracture was visible and frankly overlooked in 31 (72%) of 43. The fracture was not included on the examination in eight (19%) of 43; and it was obscured by superimposed structures or artifacts in four (9%) of 43. Ipsilateral regional injuries were present in 88 (88%) of 100. These included multiple upper rib fractures in 40 (40%), clavicular fractures in 17 (17%), acromioclavicular separation in six (6%), and "other" in 26 (26%). "Other" included subcutaneous emphysema, pneumothorax, pleural effusion, and pulmonary contusion. The presence of ipsilateral regional skeletal injuries and soft-tissue injuries after major blunt chest trauma should prompt a diligent search for concomitant scapular fractures.

Female↗
PubMed1988

Fetal choroid plexus cysts: prevalence, clinical significance, and sonographic appearance.

To determine the prevalence, sonographic appearance, and clinical significance of fetal choroid plexus cysts, we analyzed the sonograms and clinical records of 17 fetuses with cysts. Fetal and maternal age, sonographic indication, cyst size and multiplicity, and evolution on serial studies were recorded. Fetal outcome was available in 16 cases by genetic amniocentesis (n = 5) or neonatal clinical records (n = 11). The prevalence of fetal choroid plexus cysts was 0.8% (17/2084) during a 40-month period. All cysts were initially identified on sonograms performed between 14 and 21 weeks. Cysts ranged from 3 to 11 mm in size and were bilateral in four (36%) of 11 cases in which both lateral ventricles were visualized. In nine of 10 cases with serial sonograms 2-21 weeks after the initial study, the cysts were no longer present. One fetus had a small cyst persisting at term. All five cases with genetic amniocentesis had normal chromosomes. The only phenotypic abnormality in the 11 cases with clinical follow-up was a small hemangioma of the chest wall. We conclude that most fetuses with isolated choroid plexus cysts have a normal outcome and that serial sonography for cyst evaluation is not useful in determining fetal prognosis.

Brain Diseases↗
PubMed1987

Further characterization of phage T1 DNA clones.

A series of phage T1 DNA clones containing Sau3A fragments of 1 kb or more were tested for their ability to rescue the defects of amber mutations representing all known T1 genes. Rescue was detected by either complementation or recombination. These data have extended the correlation of the T1 genetic and physical maps and provided more conclusive proof that the large map distances at the left end of the genetic map reflect both increased physical separation of the known genetic markers and enhanced recombination and that the right and left chromosomal ends are recombinogenic to the same extent.

DNA, Recombinant↗
PubMed1987

Anorectal atresia: prenatal sonographic diagnosis.

To determine the prenatal sonographic findings of anorectal atresia (ARA), we retrospectively reviewed 12 proven cases. Sonography showed abnormally dilated bowel segments in five cases (42%), four of which were identified prospectively; at autopsy, two other cases showed mild colon dilatation not evident on sonograms. Bowel dilatation was not associated with the location of atresia or the presence of a fistula, but was possibly related to menstrual age. Eleven fetuses (92%) had significant other anomalies primarily related to the VACTERL syndrome (vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, radial and renal dysplasia, and limb malformations) and/or the caudal regression syndrome; of these, sonography identified one or more concurrent anomalies in seven cases. In two cases, bowel dilatation was the primary sonographic finding. Death in nine cases resulted from termination of pregnancy (four cases) or perinatal demise (five cases); three patients are still alive. We conclude that some cases of ARA can be suspected on prenatal sonograms by demonstration of dilated colon, and that the sensitivity of this finding may be related to menstrual age at the time of the examination. Distinguishing ARA from other causes of fetal-bowel dilatation is important because of the frequency of concurrent anomalies associated with ARA.

Abnormalities, Multiple↗