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Biomedical subjects

D Hahn

Publications and source records attributed to D Hahn.

At least 37 records · Page 2Linked to original sources
PubMed1990

Duplex sonography in the diagnosis of renovascular hypertension.

Duplex sonography (DS) has become a well established method for diagnosing peripheral vascular diseases. Technical developments (higher resolution of transducer and deeper penetration) have made also abdominal and retroperitoneal vessels, including renal arteries, accessible for duplex sonography. This method provides the opportunity to recognize renal artery stenoses causing renovascular hypertension without invasive procedures. We therefore examined 86 hypertensive patients with a high likelihood of renovascular hypertension. Due to technical problems (bowel gas, adipositas) we excluded 7 patients. 79 patients (17-79 years) were included in our study. Flow patterns of several renal vascular areas were evaluated while the renal artery was demonstrated on a B-scan. A spectrum analysis included the evaluation of the frequency pattern (widening of the frequency band and loss of a frequency free window below the systolic rise?), the sloping of the diastolic shoulder, and the calculation of different parameters like acceleration index, deceleration index, resistance index, acceleration time, and systolic peak velocity. The accuracy of DS in diagnosing renal artery stenoses was compared with arterial digital subtraction angiography (DSA). Renal artery stenoses was diagnosed in 21 out of 158 renal arteries (13%). Except for the systolic peak velocity no significant correlations could be found of any of the indices from spectrum analysis with hemodynamically significant stenoses (greater than 50%). However, the following 3 criteria proved to be valuable signs of a hemodynamically significant stenoses: 1) Maximal systolic acceleration greater than 3 m/s, 2) Steep sloping diastolic shoulder, and 3) Turbulence of all frequency ranges without a frequency free window below the systolic rise. Compared with DSA the sensitivity of DS was 84.0%, the specificity was 98.5%, and the predictive value 91% in significant stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Bone pain in adults as the first symptom of late congenital syphilis].

A 20-year-old woman developed multifocal bone pain. Diagnostic radiology revealed thickened periosteum, and syphilis serology was positive (T. pallidum haemagglutination test 1:5120). She also had discrete signs of congenital syphilis, with retinitis pigmentosa and Hutchinson's incisors. Skeletal scintigraphy demonstrated increased uptake even in radiologically unremarkable bones. The bone pain decreased after four-week administration of 1 M units of penicillin G daily. Scintigraphy one year later showed regression of the increased uptake, skeletal radiology did not reveal significant changes. This case shows that late manifestations of congenital syphilis still occur today. The stigmata of such an infection can be minute and easily missed. Skeletal scintigraphy is better for demonstrating active bone involvement than conventional radiology.

Adult↗
PubMed1990

Extraction of ribosomal RNA from soil for detection of Frankia with oligonucleotide probes.

Sequences of 16S rRNA of the nitrogen-fixing Frankia strain Ag45/Mut15 and the ineffective Frankia strain AgB1.9 were used to design a genus-specific oligonucleotide probe. Hybridization experiments of this Frankia probe and a second probe, specific for Nif+-Frankia strains only, were used to detect Frankia specific target sequences in RNA isolations from soil. A method is described for direct isolation of RNA from a loamy soil and a peat. Yields of about 10 ng RNA/g wet soil are obtained without detectable contamination with humic acids. Isolation of RNA after initial extraction of bacteria from soil resulted in significantly lower RNA yields, compared to the direct isolation procedure. Hybridization with both probes against rRNA isolations from Frankia-containing soil could detect target sequences within RNA isolations from 1 g wet soil with an estimated detection limit of 10(4) cells.

Actinomycetales↗
PubMed1990

Intermittent GnRH antagonist plus progestin contraception conserving tonic ovarian estrogen secretion and reducing progestin exposure.

The present study was designed to evaluate the effectiveness of a once-weekly regimen of GnRH antagonist followed by a progestin as a potential new contraceptive method. On menstrual cycle days 2, 9, 16, and 23 (onset of menses = Day 1) monkeys were divided into two groups: 1) those injected sc with 0.1 mg/kg Nal-Glu GnRH antagonist in saline and those given only vehicle (control). On cycle days 15 to 26, each treated female was administered 25 micrograms norgestimate/day orally. This was continued for three treatment cycles (84 days). Weekly injections of Nal-Glu GnRH antagonist effectively blocked completion of folliculogenesis, ovulation, and corpus luteum function as judged by serum LH, E2, and P levels. Serum progesterone was undetectable (less than 0.1 ng/ml) during the treatment cycles. Importantly, serum estradiol levels during GnRH antagonist plus norgestimate treatments were maintained at 35 +/- 7 pg/ml. Upon the cessation of norgestimate treatment on day 26 in each cycle, menses uniformly began within 2 or 3 days. Regarding recovery, apparently normal and presumably ovulatory menstrual cycles, as judged by timely estradiol elevations, midcycle LH surges, and luteal phase progesterone patterns, were manifest immediately following termination of the final GnRH antagonist plus norgestimate treatment cycle. Endometrial biopsies removed on day 26 of control cycles, and on day 26 of the third treatment cycle revealed appropriate late secretory phase endometrium having tortuous endometrial glands and superficial stromal edema. Histological sections of ovaries removed at the end of the GnRH antagonist plus norgestimate treatment revealed multiple small and medium-sized developing and atretic follicles, having maintained serial ablation of the potentially maturing follicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Magnetic resonance tomography of scaphoid pseudarthrosis: clinical and x-ray aspects].

37 patients with non-unions of fractures of the carpal scaphoid were examined with MRI and the results compared with conventional radiographs. Advantages of MRI are the documentation of concomitant soft tissue changes in the region of the pseudarthrosis, and the early detection of osteonecrosis of one of the fragments. Advantages of conventional radiographs are the exact documentation of cancellous bone morphology and the position of the fragments.

Adolescent↗
PubMed1990

Multicentre controlled trial of indoramin in the symptomatic relief of benign prostatic hypertrophy.

A group of 139 patients with symptoms of bladder outflow obstruction due to benign prostatic hypertrophy were entered into a double-blind, parallel group, multicentre study of 2 doses of indoramin versus placebo. There were 18 withdrawals or exclusions, leaving 121 patients for analysis. After 8 weeks, mean peak flow rates increased more in patients treated with indoramin 20 mg bd than in those with placebo. The difference between indoramin 20 mg nocte and placebo was not significant. The change in mean peak flow rate for the higher dose of indoramin represented an increase of 50%. Both patients and investigators reported that the patients' symptoms had improved significantly on both indoramin 20 mg bd and 20 mg nocte; 9 patients were withdrawn because of adverse events, 5 taking placebo and 2 in each of the treatment groups. It was concluded that indoramin 20 mg bd was both effective and well tolerated in the management of symptomatic benign prostatic hypertrophy.

Aged↗
PubMed1990

Evolving myocardial infarction during percutaneous transluminal coronary angioplasty: the use of portable percutaneous cardiopulmonary support.

Percutaneous transluminal coronary angioplasty (PTCA) has become an invaluable tool in the treatment of coronary artery disease. However, it is not without risks. For the PTCA patient who develops signs and symptoms of an evolving myocardial infarction, the time delay involved in the transportation of the patient from the angiography suite to the operating room becomes important. Institution of cardiopulmonary bypass in the angiography suite has enabled the successful transport of the patient to the operating room in a hemodynamically stable condition. We now present two case reports of patients treated with emergent percutaneous cardiopulmonary bypass following the development of myocardial infarction during PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1989

[In vivo 31P magnetic resonance spectroscopy and MRI in patients with superficial tumors].

Simultaneous 31P-MR spectroscopy (MRS) and MR imaging (MRI) of 10 patients suffering from superficial tumours like carcinoma, lymphoma and adenoma, revealed significantly enhanced concentrations of phosphomonoester, phosphodiester and inorganic phosphorus in the tumour, whereas the concentration of phosphocreatine was lower in comparison to muscle tissue. In all tumours the pH showed a slight alkaline shift. The existing of necrotic regions detected by MRI was accompanied by an increase of inorganic phosphorus in the spectra. A follow-up study of a patient with a lymphoma during chemotherapy showed a tumour regression, whereas the spectra indicated a continuous approach of tumour values to the muscle values.

Contrast Media↗
PubMed1989

[Gd-DTPA-supported magnetic resonance tomographic perfusion follow-up of shockwave-treated tumors].

The signal characteristics of 14 shockwave-treated and 14 solid control tumors were studied before and after injection of Gd-DTPA in an animal model. T1-weighted images of shockwave-treated tumors documented no significant signal intensity increase after contrast media injection in comparison with the untreated control tumors. The reduction of perfusion in shockwave-treated tumors can be documented in vivo by the signal intensity changes of the tumors after contrast media injection.

Animals↗
PubMed1989

Detection and quantification of chronic cerebrovascular disease: comparison of MR imaging, SPECT, and CT.

Twenty patients with angiographically proved occlusion of the internal carotid artery (ICA) (19 unilateral, one bilateral) were studied with magnetic resonance (MR) imaging, iodine-123 iodoamphetamine (IMP) single photon emission computed tomography (SPECT), xenon-133 SPECT, and computed tomography (CT). All patients had a history of stroke or prolonged reversible ischemic neurologic deficit for more than 4 weeks. By regions of interest, T1, T2, regional cerebral blood flow (rCBF), and the number and size of the lesions were determined. The data were expressed as interhemispheric ratios (diseased/nondiseased). The highest ratios obtained were for MR imaging (T1, 2.60 +/- 0.42; T2, 1.61 +/- 0.22 [mean +/- standard deviation]) followed by Xe-133 SPECT (0.58 +/- 0.13) and IMP SPECT (0.56 +/- 0.13). Correlation coefficients for MR imaging (1/T1, 1/T2) and IMP SPECT were below .21. The lesion size was greatest on IMP SPECT images, intermediate on MR images, and least on CT scans. However, MR imaging was superior in detection of pathologic areas (detection rates: MR, 100%; IMP SPECT, 91%; CT, 79%). Relaxation times do not correlate with rCBF.

Brain↗
PubMed1989

Paragangliomas of the jugular bulb and carotid body: MR imaging with short sequences and Gd-DTPA enhancement.

Twenty-six patients with glomus jugulare (16), glomus tympanicum (three), or carotid glomus (seven) tumors were examined with contrast-enhanced CT scans and MR scans without and with Gd-DTPA. MR and CT scans had similar sensitivities, but the enhanced MR scans were diagnostically more specific than either CT or nonenhanced MR. Dynamic MR scanning permitted measurement of the degree of Gd-DTPA enhancement over time. We recommend contrast-enhanced MR with short sequences and a dynamic approach in patients with suspected carotid, tympanic, and jugular paragangliomas.

Carotid Body Tumor↗
PubMed1989

Gonadotropin-releasing hormone infusion interval: importance in pharmacodynamics.

Circulating gonadotropin-releasing hormone (GnRH) levels were measured during and after intravenous infusion intervals ranging from 0.08 minutes to 5 minutes and doses ranging from 1 to 25 micrograms per pulse. In all dose groups (1 vs. 5 vs. 25 micrograms), the peak levels of GnRH decreased from the 0.08 minute to the 5 minute infusion interval. Our results suggest that the infusion interval over which GnRH is administered has profound effects on the amount, duration, and pattern of GnRH measured in the peripheral circulation.

Animals↗