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Biomedical subjects

P Barton

Publications and source records attributed to P Barton.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Sonographic staging of pancreatic cancer. Report of 100 cases].

The ultrasound studies of 100 patients with proven pancreatic carcinoma were reviewed and correlated with the intraoperative and pathoanatomic findings. Ultrasound had a sensitivity of 87% in detecting the malignant lesion. The extension of the tumour and the infiltration of peripancreatic structures and visceral vessels was interpreted correctly in 85% of the cases. The sensitivity for liver metastases was 90.9%, whereas for lymph node involvement it was 78.3%. 19 patients had carcinosis peritonei. Ultrasonography could only detect the carcinosis in two cases. Malignant ascites was found in 15% (sensitivity of US 88.2%). 31% of the pancreatic carcinomas were resectable.

Adult↗
PubMed1989

[Ultrasonic diagnosis following liver transplantation].

Realtime and duplex sonography were used routinely for the postoperative and long-term follow-up of liver transplantation patients. In the early postoperative period 90 patients exhibited diffuse (67.7%) and focal (33.3%) alterations of the liver parenchyma; in 53% of patients various liquid lesions were diagnosed in the abdominal cavity. In case of diffuse alterations of the liver parenchyma, no correlation could be established between sonomorphology and histopathologic findings; especially rejection could not be diagnosed by using sonography. In case of focal intrahepatic lesions highly echogenic areas of infarction could be differentiated from poorly echogenic changes such as necrosis, haematoma and abscess--these entities had to be further distinguished by means of CT or needle biopsy. 20 patients showed biliary pathology (biliomas: 5, cholangiectasis: 15). In 73.3% of cholangiectasis the cause of obstruction could be demonstrated sonographically (biliary thrombus, stenosis of the anastomosis of the common bile duct, recurrence of tumour). In 13 patients major vascular complications were diagnosed predominantly by means of duplex sonography (hepatic artery occlusion: 4, hepatic artery stenosis: 1, portal vein occlusion: 1, partial thrombosis of portal vein: 2, portal vein stenosis: 2, stenosis with incomplete thrombosis of the inferior vena cava: 3, VCI stenosis: 1). 13 patients developed recurrent malignancy in the late postoperative period.

Adolescent↗
PubMed1989

[X-ray diagnosis of renal osteopathy in dialysis patients with reference to clinical aspects].

Pathophysiological histological and radiological findings in renal osteodystrophy are described. Special emphasis is laid on secondary hyperparathyroidism. Preliminary results of the authors' investigations show a good correlation between radiological findings in the phalanges of the hand and the concentration of parathyroid hormone (PTH) in 14 patients. The concentration of the hormone in the blood was measured by a new "two-site" immunoradiometric assay, which is specific for the intact, biologically active hormone. Patients with high concentrations of PTH in the blood tended to have more severe radiological changes. In 4 patients for whom radiographs of the hands revealed no pathologic findings, normal PTH concentrations in the blood were measured by this method, whereas the conventional assay gave elevated hormone concentrations for the same patients. This is due to the lack of specificity of the conventional method for the intact, biologically active hormone. Nevertheless, further investigations are needed to confirm these findings.

Chronic Kidney Disease-Mineral and Bone Disorder↗
PubMed1988

[Angiodynography: technical principles and clinical uses].

Angiodynography is a newly developed system that enables Doppler sonography to be used to obtain a colour-coded real-time image of the blood vessels in the familiar ultrasound slice image. A new computerised technique allows both the familiar pulse echo signal and the Doppler shift of the signal resulting from movement in the body to be displayed for each point on the ultrasound slice plane. Stationary tissue structures are shown as the familiar grey scale image, while movement such as of the blood is shown in colour. 453 patients were examined. Normal and pathological flow measurements were obtained in the carotid artery, the jugular vein, in renal transplants, in the thyroid, the testis and in the urethra. Pathological flow velocities were visualised in stenosis, tumours and diffuse alterations of parenchyma.

Arterial Occlusive Diseases↗
PubMed1988

[Sonography of benign skin tumors].

Evaluation of 62 pigmented skin tumors of unknown pathology showed that benign and malignant tumors can easily be separated. Benign skin tumors have many internal echoes whereas malignant melanomas show an almost echo-free structure. Superficial spreading melanomas (SSM) and very flat benign tumors were both recorded as thin echogenic layers. It is not possible to differentiate them by US. Real time US is a simple non stressful, reproducible procedure that should be established as a routine diagnostic tool in dermatology.

Adult↗
PubMed1988

[Color-coded Doppler sonography of kidney transplants].

A prospective study was carried out in 81 patients to compare the ability of colour coded Doppler sonography (angiodynography) and Tc bolus examination for demonstrating renal blood supply. In patients with normal transplant function both methods performed equally well. In anuric patients angiodynography was superior to the Tc bolus examination: In three cases angiodynography was able to provide important additional information such as absence of blood flow in peripheral intrarenal vessels or missing blood supply of a transplant pole. Angiodynography seems to be able to replace the Tc bolus examination; this statement excludes very obese patients until low-frequency probes for angiodynography will be available.

Anuria↗
PubMed1988

[Color-coded Doppler sonography in thyroid diseases: initial experiences].

The thyroid gland was investigated in 43 persons (12 healthy volunteers, 31 patients with diseases of the thyroid gland) with a new colour Doppler system (angiodynography). In euthyroid persons (normal thyroid gland, diffuse or multinodular goitre) only a few vessels were detected. In cases with Graves' disease however, hypervascularization was evident. Autonomous adenomas had a hypervascular periphery, whereas our two carcinomas showed a high vascularisation in the nodule. Angiodynography might become an important diagnostic tool for the evaluation of thyroid glands. The number of radionuclide studies and punctures might be limited.

Color↗
PubMed1988

[CT before and after liver transplantation].

In our retrospective study, we evaluated the role of CT in cases of liver transplantation. 118 examinations (37 pre- and 81 post-operative) were carried out in 46 transplant recipients. Pre-operatively CT was used to exclude retroperitoneal secondary lesions, although ultrasound was superior in the region of the porta hepatis. Patency of the portal vein can be established by means of duplex sonography and CT. Portography is indicated only in exceptional circumstances. Post-operative complications (abscesses, hematomas, infarcts) can be demonstrated by CT. CT-guided fine needle biopsies and percutaneous drainage can be carried out post-operatively, even under difficult conditions. Liver cell necrosis, if extensive, represents a serious risk to transplant survival. CT may clarify this, while other problems and differential diagnosis may be solved by angiography.

Adult↗
PubMed1988

Control of myogenesis in the mouse myogenic C2 cell line by medium composition and by insulin: characterization of permissive and inducible C2 myoblasts.

Using subcloning and manipulations of culture conditions we have isolated from the mouse myogenic cell line C2 a variant cell line that we named inducible. Unlike the progenitor cells that are referred to as permissive, inducible myoblasts differentiate poorly in Dulbecco modified Eagle medium plus fetal calf serum (FCS) and require the presence of insulin at a high concentration (1.6 10(-6) M) or insulin-like growth factor I (IGFI) at a lower concentration (2.5 10(-8) M) to differentiate. Permissive and inducible myoblasts fail to differentiate when grown in MCDB202 medium plus 20% FCS, even after a prolonged arrest in G1 phase. This shows that an arrest in G1 is in itself insufficient to trigger terminal differentiation. Both cell types also exhibit distinct patterns of accumulation of muscle mRNAs corresponding to sarcomeric actins and myosin light chain MLC1A. The possibility that these two cell lines might represent two different stages of the progression of myoblasts toward terminal differentiation is discussed.

Actins↗
PubMed1987

Developmental pattern of mouse skeletal myosin heavy chain gene transcripts in vivo and in vitro.

We have studied the transcripts of the embryonic, perinatal, and adult fast myosin heavy chain (MHC) genes in mouse skeletal muscle in vivo before and after birth, and in vitro in myogenic cell lines. In vivo, in 15-day fetal muscle, embryonic and perinatal MHC mRNAs are both present, and the former is the major transcript. By 18 days the perinatal is predominant and the adult MHC mRNA appears. In beta-bungarotoxin-treated fetuses, a similar developmental pattern is detected, suggesting that it is nerve-independent and that primary myotubes alone undergo the same developmental changes. In vitro, in the absence of the nerve, embryonic, perinatal, and adult IIB MHC mRNAs accumulate. The level of the latter two isomRNAs is influenced by culture conditions.

Aging↗
PubMed1987

[Duplex sonography in the assessment of normal flow relations in the transplanted kidney].

26 patients with normal renal transplants were examined by means of duplex sonography to define normal blood flow parameters. The renal blood flow pattern showed in each segment of the renal arteries a rapid upslope in systole followed by graduate downslope in the early diastole with persistent flow throughout the diastole. There was no significant difference between the main renal artery and the three different orders of intrarenal arteries. Mistakes can be made due to flow disturbance from turbulences at the anastomosis or by obtaining signals from other vessels located near the renal parenchyma. Several (at least two) arterial signals should be obtained by aligning the transducer along the axis of the transplant renal artery and renal parenchyma. Only the strongest signals should be recorded.

Adult↗
PubMed1987

[Comparison of the value of general and oblique images and whole lung tomography in a high kilovoltage technic in the detection of pulmonary coin lesions].

The ranking of high kvp pa. and lateral chest x-ray, left and right oblique films and whole lung tomography in the detection of pulmonary coin-shaped lesions is compared. Out of a total number of 327 coin lesions in 115 patients detected by high kvp whole lung tomography, only 52% were found on pa and lateral chest films. Additional oblique films improved the score to 64%. Oblique films proved to be especially helpful in detecting pleural lesions. Although CT has a higher sensitivity in detecting nodules (with decreasing specificity) whole lung tomography will continue to play an important role in the management of tumour patients.

Diagnosis, Differential↗
PubMed1986

Actin and myosin multigene families: their expression during the formation and maturation of striated muscle.

The initial formation of skeletal muscle fibers is accompanied by the expression of muscle-type actin and myosin genes. During subsequent maturation of muscle fibers in vivo, developmental changes in the fetal/adult isoforms of these proteins occur. Skeletal muscle-specific transcripts coding for different myosin heavy chains accumulate sequentially both in vivo and in vitro. A genetic analysis demonstrates that these genes are clustered, implicating cis-acting regulatory factors. In contrast, actin and myosin light chain genes are dispersed in the mouse genome. These gene families show a different developmental "strategy": Genes expressed in adult cardiac tissue are coexpressed with the corresponding skeletal muscle sequence during fetal development. This phenomenon also occurs in adult tissue. Under conditions of cardiac overload, adult rat hearts accumulate skeletal actin mRNA and cardiac actin transcripts. In some mouse lines, a mutant cardiac actin gene locus is present. The presence of a second active upstream promoter at this locus depresses transcription of the bone fide gene, resulting in low levels of mature cardiac actin mRNA. In this situation skeletal actin gene transcripts accumulate. Genes expressed in the same fetal or adult muscle phenotype are not linked, suggesting that their coexpression is regulated by transacting factors. The promoter regions of such genes in the mouse have no common characteristics of primary structure with the exception of an E1A-type enhancer core sequence, which has a conserved 5' flanking element, seen for actin and myosin light chain genes. Reintroduction of these promoter regions into muscle cells provides a functional test for such potential regulatory sequences.

Actins↗