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Biomedical subjects

J A Bönhof

Publications and source records attributed to J A Bönhof.

At least 19 recordsLinked to original sources
PubMed1998

[Ultrasound in diagnosis of benign and malignant liver tumors].

Sonography has a high sensitivity in diagnosing circumscript lesions in the liver when modern machines are used by a skilled examiner. The exact analysis of the sonographic imaging characteristics allows definite diagnosis in the majority of cases. The high prevalence of benign liver tumors has to be considered. It is substantiated by an evaluation of 731 own patients. The characteristics of the most important circumscribed liver lesions are presented and suggestions for the diagnostic work-up are provided.

Diagnosis, Differential↗
PubMed1996

Prevalence of adrenal and extra-adrenal Conn syndrome in hypertensive patients.

BACKGROUND: Primary aldosteronism (PA) is caused by an adrenal aldosterone-producing tumor (A-APT) or adrenal hyperplasia. An extra-adrenal APT (E-APT) as a cause of PA has been reported in 5 cases. Autopsy studies show a high incidence of ectopic adrenocortical tissue. We did a prospective study of the prevalence of A-APTs and E-APTs and the biochemical features of E-APTs in patients with PA. METHODS: Hypertensive patients (N = 3900) referred to our unit were screened for PA by measuring renin activity, urinary aldosterone-18-glucuronide, tetrahydroaldosterone, and 18-hydroxycorticosterone (18-OH-B). Primary aldosteronism was found in 257 cases. The differentiation between A-APTs and adrenal hyperplasia was based on the results of postural response of renin, plasma aldosterone, 18-OH-B, computed tomography, isotope scanning, or adrenal venous aldosterone. Ultrasound examination of the abdomen was used to screen for E-APT. RESULTS: The cause of PA was bilateral adrenal hyperplasia in 101 cases, unilateral adrenal hyperplasia in 2, an A-APT in 146, and an E-APT in 1. The site of aldosterone production was uncertain in 7 patients who had normal adrenal glands on computed tomography but refused to undergo isotopic scanning and adrenal venous catheterization. Ultrasound examination disclosed normal retroperitoneum in 4 of the 7 cases but could not rule out E-APT in 3 cases. The biochemical features of the patient with the E-APT were similar to classic A-APT, with low renin, high aldosterone, and high 18-OH-B values without appropriate response to posture or to short-term volume expansion. The excision of the E-APT in the right kidney resulted in normalization of blood pressure and renin, aldosterone, and 18-OH-B levels. CONCLUSION: Although E-APT is rare, it should be considered in the interests of specific therapy for PA because aldosterone-secreting malignant ovarian tumors also have been reported.

Adrenal Cortex Neoplasms↗
PubMed1995

A new subset of mineralocorticoid hypertension with excess of 21-deoxyaldosterone and Kelly's-M1 steroid: clinical and morphological findings.

Ten cases of adrenal adenomas, one case with unilateral adrenal hyperplasia, and another case with apparent bilateral are reported, in whom an alternative pathway of aldosterone via 21-deoxyaldosterone is operative. They all manifested hypertension, low renin activity, low normal potassium values, as well as high urinary excretion rates of 21-deoxyaldosterone and its related metabolite Kelly's-M1 steroid. In all cases, urinary aldosterone metabolites (aldosterone-18-glucuronide and tetrahydroaldosterone) and aldosterone precursor 18-hydroxycorticosterone levels were normal. Hence, the adrenal lesions give rise to hyper-21-deoxyaldosteronism. 21-Deoxyaldosterone is a weak mineralocorticoid, and its elevated production in the presence of normal aldosterone can induce a pathological state of hypermineralocorticoidism. Adrenalectomy resulted in normalization of hypertension in six of eight and amelioration in two of eight cases. Six of seven adenoma cases examined as well as the case of unilateral adrenal hyperplasia were sensitive to ACTH. One of the seven adenomas and, as expected, the case with apparent bilateral hyperplasia were angiotensin responsive. Histologically and electron microscopically, the operated adenomas consisted predominantly of clear cells, characterized by mitochondria with tubulo-vesicular internal structure similar to those of the zona fasciculata (in contrast, our classical Conn's adenoma with normal 21-deoxyaldosterone excretion exhibited a more heterogenous histological appearance and were, in terms of ultrastructure, more similar to cells of the zona glomerulosa). Ultrastructurally and immunocytochemically, the clear cells of 21-deoxyaldosterone adenomas showed features of both the zona glomerulosa and the zona fasciculata and are, hence, considered to be hybrid cells. We conclude that the determination of 21-deoxyaldosterone and Kelly's-M1 should be considered in the diagnosis of mineralocorticoid-induced forms of hypertension, especially when an adrenal adenoma has been detected with an imaging procedure.

Adenoma↗
PubMed1985

A pseudolesion of the liver caused by rib cartilage in B-mode ultrasonography.

An artifactual protuberance at the surface of the liver in connection with an incomplete acoustic shadow is described. The reproduction of these phenomena in vitro was possible, providing an explanation of their origin. Rib cartilage, with its convex shape, and with the higher sound wave velocity and the higher attenuation compared with the surrounding tissue, causes these artifacts. The identification of a pseudolesion composed of these artifacts is simple if one considers its origin.

Acoustics↗
PubMed1984

[Double images in B-mode sonography due to acoustic dispersion lenses].

Clinical observations revealed that duplication artifacts in B-mode-ultrasound depend on rib cartilage in the sound field. The in-vivo conditions were imitated by watertank experiments with an acrylic glass magnifier which has the properties of an acoustic dispersing lens. With this the duplication artifacts proved to be caused by acoustic dispersing lenses, in-vivo due to rib cartilage, for example.

Cartilage↗
PubMed1984

Acoustic dispersing lenses cause artifactual discontinuities in B-mode ultrasonograms.

Artifacts as disruptions and duplications of the diaphragm, gallbladder wall, posterior wall of the left ventricle, etc., are often seen in B-mode ultrasound examinations. To identify their cause, in vitro experiments were carried out. These investigations showed that these artifacts are caused by acoustic dispersing lenses. In vivo they are due to rib cartilage and in vitro they can be reproduced by introducing an acryl lens into the sound field.

Cartilage↗