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Biomedical subjects

H M Klein

Publications and source records attributed to H M Klein.

47 records · Page 3Linked to original sources
PubMed1990

[Angiography and angiotherapy in diseases of the pelvic organs].

The value of angiography is based on the fact that it enables the imaging of vascular processes (haemorrhage, aneurysm) and occasionally also the imaging of the vascular supply of tumors not related to any organ. Transarterial treatment procedures in the pelvic region, whether embolisation or intra-arterial chemoembolisation or intravasal radiotherapy, are on the whole rarely employed. They are important in palliative therapy of advanced and often inoperable neoplasms that cannot be treated otherwise. Transcatheter embolisation is an imhaemorrhages in the region of the a. iliaca int. or for arteriovenous malformations.

Aneurysm↗
PubMed1989

The utility of the panic disorder concept.

In this paper we discuss the theory that agoraphobic avoidances are central and spontaneous panics an epiphenomenon to the development of agoraphobia. Moreover we discuss the theory that posits a fixed cognitive-catastrophizing set as causal for panic. We conclude these theories do not fit the facts. We argue that it is important to distinguish between spontaneous panic and chronic or anticipatory anxiety and avoidance. Such a distinction allows for an understanding of the roles of anti-spontaneous panic medications such as tricyclics and MAOI's as well as exposure therapy, in the treatment of panic disorder with agoraphobia. The former serves the purpose of blocking panic attacks while the latter undermines phobic avoidance, but only after the panic attacks have ceased through proper medication. We conclude that recognizing the key role of spontaneous panic and its variants in anxiety nosology is a necessary guide for etiological, psychophysiological and therapeutic research in this rapidly developing area.

Agoraphobia↗
PubMed1989

Pulsatile GnRH-therapy in oligozoospermic men does not improve seminal parameters despite decreased FSH levels.

In order to evaluate GnRH administration for the treatment of infertile men with elevated serum FSH levels we administered GnRH in pulses via portable electronic infusion pumps initially to seven patients with low sperm counts and high FSH values over 12 weeks and later to nine further patients over 24 weeks who also underwent testicular biopsies. Fifty microlitres containing 5 micrograms GnRH were infused subcutaneously for 1 min every 120 min in the short-term study and every 90 min in the long-term study. Although FSH levels could be lowered in both groups of patients, none showed any improvement in sperm count or other seminal parameters. Therefore, pulsatile GnRH treatment cannot be recommended for therapy of severe oligozoospermia with elevated FSH levels.

Adult↗
PubMed1986

Topical immunotherapy changes the composition of the peribulbar infiltrate in alopecia areata.

It has previously been shown that, in patients with untreated progressive alopecia areata (AA), the peribulbar T4/T8 ratio is about 4:1. In the present study, the immunohistochemical findings obtained in untreated AA patients were compared to those obtained in patients who had received topical immunotherapy with diphencyprone. The untreated group consisted of 5 patients with progressive AA and 5 patients with inactive AA. The treated group consisted of 5 patients with a good response to diphencyprone and 5 patients with little or no hair regrowth after treatment. In untreated patients with progressive AA, the mean peribulbar T4/T8 ratio was 4:1, whereas in untreated patients with stable AA, the ratio was 2:1. In the treated patients with a good response to diphencyprone, the mean T4/T8 ratio was 1:1, while in the patients with poor or no response to treatment, the ratio was 0.7. In conclusion, topical immunotherapy considerably alters the peribulbar T4/T8 ratio in AA. The results are consistent with, but do not prove, the concept of topical immunomodulation.

Administration, Topical↗
PubMedDate not supplied

3D-surface reconstruction of intravascular ultrasound images using personal computer hardware and a motorized catheter control.

A system for three-dimensional (3D) presentation of intravascular ultrasound (US) images was designed. A standard hardware configuration based on personal computer equipment was used for acquisition and processing of image data. Pullback imaging with the US catheter was controlled by a specially designed motor assembly and performed either in equidistant 1-10 mm steps or at a constant retraction speed. Curvature of the vessel was documented on biplane digital subtraction angiograms and the US images were arranged according to the vessel shape in the angiograms. 3D reconstruction appears essential for spatial orientation of intravascular US and may be helpful in the planning of vascular interventions for a better appreciation of the extent and morphology of vascular lesions.

Blood Vessels↗
PubMedDate not supplied

Computed tomography and magnetic resonance imaging in the preoperative work-up for cochlear implantation.

The role of CT and MRI in the evaluation of patients for possible insertion of a multichannel intracochlear hearing device was appraised. The study included 52 patients who underwent both CT and MRI examinations, 40 of whom were later operated on. Coronal and axial T2-weighted spin-echo sequences were performed in 25 volunteers with normal hearing and in 47 adult patients. In 5 patients, instead of a T2-weighted spin-echo sequence, a T2*-weighted gradient echo 3D sequence with axial presaturation was used. In 39 patients with normal appearances on CT and MRI, the implant device was successfully inserted. One patient who underwent surgery had a reduced cochlear signal on MRI but a normal CT scan; however, at surgery, the implant device could only be inserted into the first turn of the cochlea, due to fibrous obliteration. In 3 of 12 patients who were not operated upon, the results of diagnostic imaging indicated that the insertion of an intracochlear hearing device was not useful. Our experience indicates that, with reduced cochlear fluid signal intensities on MRI, fibrous obliteration of the cochlear turns is likely to be present. MRI proved to be a useful adjunct to CT, but the latter was necessary for the evaluation of bony abnormalities. Gradient echo sequences can successfully replace time-consuming T2-weighted spin-echo sequences.

Adolescent↗
PubMedDate not supplied

CT and MRI of experimentally induced mesenteric ischemia in a porcine model.

OBJECTIVE: Our goal was to assess the value of CT and MRI for the detection of bowel wall changes in experimentally induced mesenteric ischemia. METHODS: in 18 female pigs, a percutaneous embolization of the superior mesenteric artery was performed with buthyl-2-cyanoacrylate and Lipiodol (1:1) (experimental group). In six animals, only diagnostic imaging and histologic evaluation were performed (control group). CT was carried out 3, 6, and 12 h after occlusion. Incremental CT (1 s scan time, 5 mm slice thickness, 7 mm increment, 120 kV/290 mAs) and spiral CT (slice thickness 5 mm, pitch 1.5, 120 kV/165 mA) were performed pre and post contrast injection (Somatom Plus/Siemens). Serial CT was carried out after intravenous contrast injection (1 ml/kg, 2 ml/s). MRI (Magnetom 1.5 T; Siemens) was performed with T1 (pre and post 0.01 mmol/kg Gd-DTPA; Magnevist; Schering, Germany), T2, and proton density images in axial orientation. Slice thickness was 3 mm and slice gap 1 mm. Additionally, a T1-weighted GE sequence (multislice FLASH 2D) was obtained in dynamic technique (before and 30, 60, and 90 s after contrast agent injection) with a slice thickness of 5 mm. Biometrical monitoring included blood pressure, heart frequency, blood cell count, electrolyte status, blood gas analysis, and determination of serum lactate. Image evaluation included morphological analysis and determination of the enhancement pattern. Histological specimens were obtained and analyzed according to the Chiu classification. RESULTS: The histologic workup of the specimen 3, 6, and 12 h after vascular occlusion revealed an average Chiu state 3, 4, and 5. On CT, the bowel wall had a thickness of 4.7 mm on average in the ischemic segments. There was a significant difference from the control group (average 3 mm). Free intraperitoneal fluid and intramural gas were seen after 12 h of ischemia in 80%. In ischemic bowel segments, no mural enhancement was seen. Normal segments and the bowel of the control animals showed an enhancement of 34 HU on average (SD = 3.1 HU; p.<0.01). In MRI, S/N and C/N differed significantly between experimental and control groups in T1 and proton density images. In ischemic segments of all phases, the bowel wall did not show contrast enhancement. Healthy segments and bowel of control animals showed a significant enhancement (p<0.01). CONCLUSION: Cross-sectional imaging has a high sensitivity for delineation of ischemic bowel wall segments. The enhancement pattern of the bowel wall enables detection of location, extent, and cause of a acute arterial mesenteric ischemia with high accuracy in an early phase.

Animals↗