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M Holla

Publications and source records attributed to M Holla.

4 recordsLinked to original sources
PubMed2006

[An asymmetrical face due to torticollis in two young children].

In 2 girls, 4 years and 8 months of age, respectively, torticollis had been diagnosed a few weeks after birth. Kinesiotherapy, given for a period of 1 year and 6 months, respectively, had little effect. Both girls were then referred to the Orthopaedic Outpatient Clinic where a shortened sternocleidomastoid muscle and an asymmetrical face were diagnosed. The shortened muscle was cleaved surgically. Over half a year later, the face of the older child was still asymmetrical but that of the younger child symmetric. It is recommended that children with torticollis due to a shortened sternocleidomastoid muscle first be given stretch exercises under the guidance of a physiotherapist. If the result at the age of 1 year is unsatisfactory, an orthopaedic surgeon can then cleave the muscle.

Child, Preschool↗
PubMed2001

Flow-directed microcatheters for cerebral embolizations using Ethibloc--an in vitro study.

We conducted an in vitro performance study to test the flow-directed Spinnaker microcatheter for potential endovascular embolizations with Ethibloc as embolic agent. We performed in vitro testing using 50 Spinnaker 1.8F hydrophilic infusion microcatheters of three different types. As embolic agent, different mixtures of Ethibloc and Lipiodol (E/L 1:1, 1:2, 1:3) were used. In an in vitro setting, each catheter was injected to a maximum of ten times (E/L 1:1, n = 20 catheters; E/L 1:2, n = 20; E/L 1:3, n = 10). In addition, we evaluated the thinner Spinnaker 1.5F microcatheter (165/20, n = 10). Five Spinnaker 1.5F catheters were each injected with a mixture of Ethibloc and Lipiodol (E/L 1:2 and 1:3). When a mixture of E/L 1:1 was used, 9 of 20 (45%) Spinnaker 1.8F microcatheters ruptured distally near the tip of the microcatheter, each during injection nos. 5-9. One Spinnaker 1.8F was distally occluded after the fifth injection. With a mixture of E/L 1:2, 4 of 20 (20%) Spinnaker 1.8F microcatheters ruptured distally, during injection no. 6 (n = 2), 7 (n = 1), and 8 (n = 1). With a mixture of E/L 1:3, all ten Spinnaker 1.8F microcatheters could be injected without any problems. All ten microcatheters of the thinner Spinnaker 1.5F ruptured (10-18 cm proximally to the catheter tip). This in vitro study using the flow-directed Spinnaker microcatheter revealed that microcatheters can rupture. The Spinnaker 1.8F can rupture when a mixture of Ethibloc and Lipiodol 1:1 or 1:2 and more than four injections are used. The Spinnaker 1.8F does not rupture when a mixture of E/L 1:3 is used, or with a mixture of E/L 1:1 or 1:2 and injecting to a maximum of four times. The Spinnaker 1.5F microcatheter is not suitable for embolizations using Ethibloc. For embolizations with Ethibloc we therefore recommend the use of a guidewire-directed microcatheter.

Catheterization↗
PubMed1998

Dysprosium-DOTA-PAMAM dendrimers as macromolecular T2 contrast agents. Preparation and relaxometry.

RATIONALE AND OBJECTIVES: The authors have investigated dysprosium [Dy]-DOTA-PAMAM, generation 5 (G = 5) dendrimers as a possible new class of macromolecular T2 contrast agents. The use of DOTA provides a metal complex with greater stability than can be achieved using DTPA as ligand, an important factor in the design of blood pool agents with long half-lives. METHODS: Generation 5 ammonia-core PAMAM dendrimers were linked to the bifunctional ligand p-SCN-Bz-DOTA. After determination of the number of conjugated DOTA molecules by 1H nuclear magnetic resonance, Dy3+ was titrated at a 90% molar ratio. For comparison, single ionic chelates of Dy-DTPA and Dy-DOTA also were prepared. Using a variable field relaxometer, T1 and T2 relaxation times were measured at 13 different field strengths from 0.05 to 1.5 T and temperatures of 3, 10, 20 and 37 degrees C. RESULTS: The synthesis resulted in a preparation with 76 DOTA and 68 Dy3+ ions per dendrimer molecule. The T1 relaxivity values for Dy-DTPA, Dy-DOTA, and the Dy-DOTA-based dendrimer all were independent of field strength, with values between 0.12 and 0.20 mM-1 sec-1. At lower fields (0.05-0.1 T), 1/T2 was identical to 1/T1. At higher fields, however, 1/T2 increased quadratically with field strength, with a strong dependence on temperature. The field-dependent component of 1/T2 was up to three times higher for the Dy-DOTA-based dendrimer compared with the single chelate molecules, with coefficients of 0.37 to 0.03 sec-1/Tesla2 for T = 3 to 37 degrees C. CONCLUSIONS: The results are interpreted with the "inner sphere" theory of susceptibility effects (Curie spin relaxation). The large temperature dependence suggests that the dominant mechanism of relaxation is the contact interaction effect, with the proton residence time as the primary time constant. This largely unexplored relaxation mechanism has the potential to create a new class of T2-selective contrast agents.

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