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Biomedical subjects

M Langer

Publications and source records attributed to M Langer.

At least 487 records · Page 27Linked to original sources

Severe Legionella pneumophila infection in a patient with hairy cell leukemia in partial remission after alpha interferon treatment.

Legionella pneumonia is an increasingly frequently reported complication in immunocompromised patients, particularly patients with hairy cell leukemia (HCL) in active phase. The most important predisposing factor seems to be the quantitative and qualitative defect of the monocytic-macrophagic system characteristic of HCL. We report a case of severe Legionella pneumophila infection with multisystem involvement in a patient with HCL in stable partial remission obtained after therapy with interferon. In our patient recovery of a normal monocyte count did not protect against a legionella infection, indicating that this pathogen should always be sought in HCL patients even those in clinical and hematologic remission. Early diagnosis and appropriate treatment may reduce the mortality of this serious complication.

Adult↗

Acute effect of atenolol on serum thyroid hormones in hyperthyroid patients.

The effect of atenolol on serum thyroid hormones levels is controversial. To get more information on this problem we studied the effect of propranolol and atenolol on plasma thyroid hormone concentrations in 20 thyrotoxic patients. Propranolol but not atenolol caused a significant decrease in T3 levels whereas no significant changes wee observed in T4 levels after both propranolol and atenolol administration.

Adult↗

Effect on intimal hyperplasia of dexamethasone released from coated metal stents compared with non-coated stents in canine femoral arteries.

PURPOSE: Polymer-coated, dexamethasone (DXM)-releasing stents were tested in order to assess the efficacy of DXM released locally for the prevention of stent restenosis due to intimal hyperplasia. METHODS: Strecker stents coated with a biodegradable membrane containing DXM were implanted percutaneously into the femoral artery in 14 dogs. The contralateral artery received a conventional non-coated stent serving as control. The drugs are eluted by degradation of the carrier membrane. Follow-up intraarterial digital subtraction angiography (DSA) was obtained at 3, 6, 9, 12, and 24 weeks with subsequent autopsy. Specimens for gross and microscopic pathology were obtained and histomorphometry was performed. RESULTS: Four of 14 DXM-coated stents showed thrombotic occlusion within the first 3 weeks; ten DXM-coated stents remained patent. At follow-up DSA, DXM-coated stents showed a significantly wider lumen than the non-coated stents. At morphometry there was less intimal hyperplasia over DXM-coated stents than over non-coated stents (p < 0.05). CONCLUSION: DXM-coated stents reduce neointimal hyperplasia in dogs when compared with non-coated stents.

Angiography↗

99mTc-labeled neuropeptide Y analogues as potential tumor imaging agents.

The possible use of neuropeptide Y (NPY) as a novel radiopeptide has been investigated. NPY is a 36-amino acid peptide of the pancreatic polypeptide family, which is expressed in the peripheral and central nervous system, and is one of the most abundant neuropeptides in the brain. Its receptors are produced in a number of neuroblastoma and the thereof derived cell lines. As structure-activity relationships of NPY are well-known, we could assume where a radionuclide might be introduced without affecting receptor affinity. We applied the novel [99mTc(OH2)3(CO)3]+ aqua complex and PADA (2-picolylamine-N,N-diacetic acid) as bifunctional chelating agent. The peptides were synthesized by solid-phase peptide synthesis, and PADA was coupled to the side chain of Lys4 of the resin-bound peptide. Upon postlabeling of [K4(PADA)]-NPY, 99mTc(CO)3 did not only bind to the desired PADA, but presumably as well to the His in position 26. Since the replacement of His26 by Ala only slightly decreased binding affinity, [K4(PADA),A26]-NPY was specifically postlabeled, and the 185Re surrogate maintained high binding affinity. Furthermore, the prelabeling approach has been applied for the centrally truncated analogue [Ahx5-24]-NPY, which is highly selective for the Y2 receptor. The resulting Ac-[Ahx5-24,K4(99mTc(CO)3-PADA)]-NPY was produced with a yield of only 16%. Therefore, postlabeling was applied for the short analogue as well, again substituting His26 by Ala. Competitive binding assays using (185)Re as a surrogate for 99mTc showed high binding affinity of Ac-[Ahx5-24,K4(185Re(CO)3-PADA),A26]-NPY. Internalization studies with the corresponding 99mTc-labeled analogue revealed receptor-mediated internalization. Furthermore, biodistribution studies were performed in mice, and stability was tested in human plasma. Our centrally truncated analogue revealed a 6-fold increased stability compared to the natural peptide NPY. We conclude that Ac-[Ahx5-24,K4(99mTc(CO)3-PADA),A26]-NPY has promising characteristics for future applications in nuclear medicine.

Animals↗

[Opiate addiction in gravidity - consequences for the newborn. Results of an interdisciplinary treatment concept].

AIMS: To evaluate the outcome of infants of drug dependent mothers (IDM) after establishing an interdisciplinary attention concept at the University Hospital in Vienna. To compare the influence of different maintenance agents on neonatal morbidity. PATIENTS AND METHODS: All newborns of opiate dependent mothers were prospectively included from III 1995 to IX 1999. The following data were collected: maintenance agent (methadone, slow release morphine, buprenorphine), infectious status, demographic data, congenital malformations, perinatal complications, as well as incidence and duration of the neonatal abstinence syndrome (NAS). Medical treatment with phenobarbital (1995 - 96) or morphine hydrochloride (MoHCl) (1997 - 99), respectively, was indicated when Finnegan score exceeded 10. RESULTS: 88 neonates (38 females/50 males) with a median gestational age of 39 weeks were included, 18 (20.5 %) were born prematurely. The median birthweight was 2905 g, 24 (27.3 %) infants were small for date (< 10th percentile), 15 (17 %) microcephalic. The malformation incidence was 7.4 %. 63 (72 %) of all newborns had to be treated due to abstinence syndrome: in the methadone group 76 %, in the morphine group 93 %, but in the buprenorphine group 19 % only (p < 0.01). Median duration of withdrawal was 15.1 days (d) with significant difference after antenatal buprenorphine exposure compared to methadone and morphine exposure (8.3 d versus 15 d and 16.5 d respectively). In neonates treated with phenobarbital duration of NAS was 17.6 d, whereas NAS in infants with MoHCl therapy lasted 12.8 d (p < 0.05). CONCLUSION: Incidence and duration of NAS after buprenorphine exposure was significantly lower than after methadone and morphine exposure. Withdrawal time under morphin-hydrochloride therapy was reduced by one third compared to treatment with phenobarbital.

Buprenorphine↗

The windblown hand - diagnosis, clinical picture and pathogenesis.

The syndrome of the windblown hand deformity is a complex constellation of malformations affecting not only the head and the feet but also the hands in a quite distinct manner. In the hand, it involves congenital bilateral flexion contracture with ulnar deviation of the metacarpophalangeal joints. The thumb is characteristically adducted (reaching the palm; "thumb-in-palm deformity") with flexion of the MP joint and hyperextension of the IP joint. The etiology is basically unknown. We present two theories based on knowledge derived from the disciplines of evolution biology and embryology. We believe that the atavistic appearance of phylogenetically primitive muscle groups in conjunction with an impaired rotation of the extremities during embryological development account for this malformation syndrome.

Abnormalities, Multiple↗

A new clamping technique for biomechanical testing of tendons in small animals. aprobst@uni-muenster.de.

When biomechanical properties of tendons are studied, the technique of clamping the tendons in the testing machine presents a methodological challenge, especially when murine tendons are examined. These short tendons tend to rupture at the transition line to the fixation, leading to false interpretations. Therefore a new clamping technique for investigation of healthy murine Achilles tendons (n = 50) was developed, in which the intramuscular tendon fibers were fixed between two paper strips and the calcaneus was wedged into a conical slot in a wooden block and then mounted in the testing machine (n = 20). This technique was compared with the conventional clamping technique that fixes both ends of the tendon by clamps (n = 15) and an earlier described method that used glue or plastic cement for the fixation of the intramuscular tendon fibers and calcaneus in the testing machine (n = 15). When tested by the new clamping technique, 17 tendons ruptured intratendinously at a mean tensile force of 8.4 +/- 1.1 N. Three Achilles tendons (17%) tore at the site of paper fixation and had to be excluded from investigation. Data from 73% of the measurements fixed by gluing had to be excluded because slippage of the proximal tendon fibers and contamination of the tendon with glue occurred. All the conventionally clamped tendons ruptured at the site of fixation at a mean tensile force of 6.1 +/- 2.3 N (p < .05). This was 30% lower than with the new clamping technique. Thus, the newly developed clamping technique enables investigators to obtain more valid biomechanical studies of the murine Achilles tendon.

Achilles Tendon↗

The effect of selenium deficiency on the feed consumption and growth of goats.

The feed consumption of goats was only reduced after considerable Se depletion. The conversion of Se-depleted animals to an Se-rich ration increased feed consumption within one day. An intrauterine Se deficiency (less than 38 micrograms Se/kg DM of the ration) did not induce intrauterine growth depression in kids. Se depletion led to a highly significant postnatal growth depression which increased with advancing Se depletion both during the lactation period and after weaning.

Animals↗

Subacute and chronic cerebral infarctions: SPECT and gadolinium-DTPA enhanced MR imaging.

Single photon emission computed tomography (SPECT) examinations of regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) were carried out in 23 patients with 19 subacute and 7 chronic cerebral infarctions. Corresponding magnetic resonance (MR) examinations (unenhanced and contrast enhanced scans) were done within a time interval of 2 days. Although all subacute lesions showed an increased rCBV, the rCBF could be either increased or decreased. Contrast enhancement in MR was associated with increased rCBV but not with increased rCBF. In all chronic lesions rCBV and rCBF were decreased and there was no contrast enhancement detectable in MR. The application of Gd-diethylenetriamine pentaacetic acid as contrast agent in MR demonstrates blood-brain barrier disruption as focal or gyral contrast enhancement in cerebral infarction. The SPECT examinations revealed an increased rCBV indicating a vasodilation or vasoparalysis. The rCBF was either increased or decreased depending on the collateral formation or recanalization of occluded vessels.

Adult↗

MRI of lymphomas of the orbits and the paranasal sinuses.

PURPOSE: The purpose of this study was to point out MR characteristics of non-Hodgkin lymphomas of the orbits and the paranasal sinuses and the benefit of fat-suppressed contrast-enhanced sequences. METHOD: The MR images of 16 patients with lymphoma of the orbits and the paranasal sinuses were retrospectively analyzed for signal intensity, contrast enhancement, bone destruction, and mass effect. The findings were confirmed by means of biopsy (Stage IE disease) or follow-up imaging after chemotherapy (Stage IV disease). RESULTS: MRI clearly delineated the extension of the lymphomas. On the T1-weighted images, the signal intensity of the lymphoma was hypointense compared with the gray matter of the brain in 12 cases and intermediate in 4 cases. The T2-weighted fast SE images showed a hyperintense signal in 12 cases, intermediate in 3 cases, and even hypointensity in 1 case. All lesions enhanced after intravenous Gd-DTPA administration, reliably visible in the T1-weighted fat-suppressed sequences but not visible in three cases in the T1-weighted SE sequences. Bony wall destruction was evident in cases with paranasal but never in isolated orbital lymphoma. CONCLUSION: While extension of lymphoma can be accurately described by MRI, a specific diagnosis is not achievable on the basis of signal intensities and enhancement patterns alone. Therefore, at least in cases of suspected Stages IE and IIE, biopsy proof is needed. Fat-suppressed contrast-enhanced sequences possess the highest detection rate and should therefore always be applied.

Adolescent↗

Radiologic findings in lymphangioma of the posterior tibial nerve.

A case of lymphangioma of the posterior tibial nerve is reported. MRI showed an elongated multiseptated cystic lesion along the tibial nerve leading to axonal degeneration and progressive left calf pain. A similar cystic lesion in a second patient was shown to be a ganglion. The diagnosis was made by surgical resection.

Adult↗

Contrast-enhanced subtraction MR angiography in occlusive disease of the pelvic and lower limb arteries: results of a prospective intraindividual comparative study with digital subtraction angiography in 76 patients.

PURPOSE: The purpose of this work was to evaluate the feasibility and clinical use of MR angiography (MRA) for examining the pelvic and lower limb arteries in patients with arterial occlusive disease. METHOD: Seventy-six patients with clinical signs of peripheral arterial occlusive disease were included in the study. MRA was performed using a fast contrast-enhanced high-resolution 3D technique that covered the area from the distal abdominal aorta to the distal lower limbs in two examination steps. RESULTS: In all patients, diagnostic images comparable with those of conventional intraarterial digital subtraction angiography (DSA) could be obtained. No false-negative findings were seen in the iliac, femoral, or popliteal arteries. Ten to 16% of the mild stenoses and 6-14% of the severe stenoses, mainly in the crural vessels, were overgraded compared with intraarterial DSA. Particularly in patients with proximal severe obstructions or occlusions, the crural segments could be depicted more clearly due to decreased arterial runoff in conventional angiography. CONCLUSION: The consistency of the excellent depiction of the vascular territories of the distal aorta and the pelvic and lower limb arteries in a standardized setting suggests great potential for the use of MRA in the primary diagnosis of peripheral arterial occlusive disease.

Aged↗

Cardiac phase contrast gradient echo MRI: characterization of abnormal left ventricular wall motion in patients with ischemic heart disease.

PURPOSE: In our patient study, we examined the clinical usefulness of phase contrast velocity mapping for the detection and characterization of localized abnormalities of left ventricular motion. MATERIALS AND METHODS: Velocity encoding is based on the fact that motion in the presence of a magnetic field gradient causes a change of the phase of the MRI signal that is proportional to the velocity of tissue motion. Left ventricular motion was characterized by parameters describing rotation and contraction/dilatation, respectively. We examined 34 patients with localized abnormalities of left ventricular motion due to ischemic heart disease. RESULTS: Three patients could not be sufficiently evaluated due to technical problems including varying positions of the heart during successive breathhold periods. In 27 of the remaining 31 patients, MRI could demonstrate abnormal radial velocities that corresponded fully or partly with perfusion deficits in single photon emission computed tomography or positron emission tomography. The abnormalities were most pronounced in early diastole. Rotational velocities did not show any regional changes. CONCLUSION: Our study showed that our technique is suitable for the detection and characterization of localized abnormalities of left ventricular motion in patients with ischemic heart disease.

Adult↗

Renal norepinephrine content decreases after chronic flow probe implantation.

Electromagnetic flow probes were chronically implanted around the left renal artery in 6 female beagle dogs. 3-10 months after implantation, renal cortex norepinephrine contents of right and left kidneys were compared (liquid chromatography). In 4 out of the 6 dogs investigated 3-6 months after implantation, the norepinephrine content of the left kidney was reduced by 27-72%. In 2 dogs investigated 7 and 10 months after implantation, the difference between left and right kidney was not significant. These findings should be taken into consideration when interpreting results from chronically instrumented kidneys.

Animals↗

Reduction of hepatic reperfusion injury by indomethacin-mediated vasoconstriction: a rat model with temporary splenocaval shunt.

For reduction of radical formation during reperfusion, a lower oxygen supply by limiting the reperfusion flow rate should be beneficial for the organ. Thus, indomethacin was given prior to reperfusion for induction of temporary postischemic vasoconstriction. In an in vivo model (female Wistar rats, 200-250 g, n = 16) with portal decompression by a splenocaval shunt, hepatic ischemia was induced for 30 min by cross-clamping of the hepatoduodenal ligament followed by portal intravenous injection of indomethacin (2 mg/kg body wt) at the end of ischemia. Liver injury was assessed by serum levels of Aspartat-aminotransferase (ASAT) and Alaninaminotransferase (ALAT) that were determined prior to ischemia, on days 2, 4, 6 and 21 postoperatively. The local tissue pO2 was measured preischemically, 1 h after reperfusion and on day 21. Application of indomethacin significantly reduced the local tissue-pO2 by about 50% after 1 h of reperfusion (p < .05). The increase in serum ASAT levels on day 2 was significantly diminished after indomethacin application (p < .05). ALAT values on day 2 showed a significant increase in the control group but did not differ from baseline in the indomethacin group. These data support the hypothesis that temporarily limited reperfusion results in an amelioration of reperfusion injury, although further studies with more selectively vasoactive agents must still be performed since indomethacin also has a major effect on the eicosanoid metabolism.

Animals↗