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M Dittmann

Publications and source records attributed to M Dittmann.

At least 19 recordsLinked to original sources
PubMed2000

A microfluidic system for high-speed reproducible DNA sizing and quantitation.

Microfabrication technology was used to develop a system consisting of disposable glass chips containing etched channels, reagents including polymer matrix and size standards, computer-controlled instrumentation for performing electrophoretic separations and fluorescence detection of double-stranded DNA, and software for automated data analysis. System performance was validated for separation and quantitation reproducibility using samples varying in amount and size of DNA fragments, buffer composition, and salt concentrations. Several applications of the microfluidic system for DNA analysis have been demonstrated, such as of polymerase chain reaction (PCR) products, sizing of plasmid digests, and detection of point mutations by restriction fragment length polymorphism (RFLP) mapping.

Animals↗
PubMed1998

[New results in the visualization of the spinal dura mater with scanning electron microscopy].

UNLABELLED: Although there are various published descriptions of the dura mater spinalis [4, 7, 9, 11, 16], some points relating to the texture of the collagen fibres in the dura have still not been adequately explained. In this study the orientation of the collagen fibril bundles was revealed with the aid of scanning electron microscopy, and our observations have yielded new insights into the three-dimensional structure of the human dura mater spinalis. MATERIALS AND METHODS: The preparations used were taken from the bodies of four persons who had died of acute cardiac infarct at the ages of 70-78 years. The histories of these patients gave no indications of earlier neurological, endocrine or septic illnesses. The tissue examined was taken 8-12 h after death in all cases; it was immediately fixed in glutaraldehyde and then processed for scanning electron microscopy in the usual way. RESULTS: In the outermost (epidural) layer of the dura mater spinalis the collagen fibres are bunched together in bands that run in all directions. Elastic fibres 2 mm thick are woven into this three-dimensional network of collagen systems. On the inside (the arachnoid side) thin collagen fibres are fused into layers in such a way that the innermost layer resting on the arachnoid has a smooth, shiny appearance comparable to that of a serosa. It is attached to the actual dura with a supporting band of connective tissue. Rests of the subdural neuroepithelium could contribute to the smooth appearance of the superficial aspect. CONCLUSIONS: The outermost layer of the dura is made up mainly of collagen fibres, which run in all three directions--longitudinal, horizontal and transverse--both singly and in groups. These findings are at odds with "classic" descriptions, according to which the fibres in the dura mater spinalis all have a parallel course with a longitudinal orientation in tangential sections.

Aged↗
PubMed1997

[Electron microscopy of the lesions produced in the human dura mater by Quincke beveled and Whitacre needles].

INTRODUCTION: Comparisons of Quincke needles and non traumatic "pencil point" needles in recent years have reported lower rates of post dural puncture headache using the later type. Our new understanding of the morphology of the human dura mater motivated us to study dural lesions caused by the Whitacre 25 G and Quincke 26 G needles, using scanning electron microscopy with the aim of determining whether there is an anatomic basis for the different outcomes. METHOD: The dura mater from three fresh cadavers of individuals aged 65, 70 and 72 years were punctured 40 times at an angle of 90 degrees each time. The Whitacre 25 G needle was used for 20 punctures and the Quincke 26 G needle was used for the other 20. Half the punctures were performed with the bevel in the parallel alignment and the other half with the bevel perpendicular to the spinal column. Fifteen min after causing the punctures, specimens were fixed in solutions of glutaraldehyde phosphate buffer and dehydrated in acetone. After critical point removal of the acetone, after the specimens were treated with carbon and metallized with gold. The lesions were examined externally and internally and expressed as the ratio of area of lesion to diameter of the needle that had caused them. RESULTS: Whitacre needle: each lesion consisted in the superimposition of multiple damaged layers that started to close individually. After 15 min the outermost layers were 90% closed and the innermost ones had closed entirely. Layers in the arachnoid surface of the dura mater had closed from 86 to 88%, while deeper layers in the thick part had closed 97 to 98%. Quincke needle: lesions were V-shaped or half-moon shaped, much like the opening formed by a can opener, on both the external and internal surfaces. Alignment of the bevel of the needle parallel to the spinal column did not lead to a different shape of puncture. After 15 min the lesions had closed 94 to 95% on the epidural surface and 95 to 96% on the arachnoid side, a difference attributable to the retraction of the arachnoid layers over the spinal column. CONCLUSION: Non traumatic beveled dural needles, termed "pencil point needles", only partially separate dural fibers, and lesions caused by these needles develop in a more complex way. The Quincke 26G needle produced a puncture that is morphologically different from that caused by the Whitacre 25G needle, although lesions produced by both types close more than 94% after 15 min. We believe the size of the lesion caused by these needles does not explain the difference in post dural puncture headache due to loss of spinal fluid.

Aged↗
PubMed1996

[Analysis of the external and internal surface of human dura mater with scanning electron microscopy].

INTRODUCTION: In recent years several studies have raised questions about the anatomy of the human dura mater. Our objective has therefore been to examine its tridimensional structure with the aid of the scanning electron microscope. METHOD: Samples were taken from 4 human cadavers (70, 72, 77 and 78 years old) between 8 and 12 hours after death. After fixing in glutaraldehyde phosphate buffer, dehydration in acetone and elimination of the acetone at the critical point, treatment with carbon and metallization with gold, the external and internal surfaces were examined. RESULTS: The external, or epidural, surface of the dura mater is made up of thin collagen fibers joined in bands running in different directions. The outer surface and lower layers of the dura contain elastic, interwoven fibers surpassing 2 microns in diameter. The inner surface, which is smooth and glossy, is formed of thin ribbons of arachnoids that are fused and tightly attached to the structure of the dura mater. CONCLUSION: The outer surface of the dura mater consists mainly of collagen fibers which alone or in groups run in different directions: longitudinally, horizontally or obliquely, depending on the are studied. These findings contradict the classical descriptions of the dura mater as having parallel, longitudinally placed collagen fibers in the tangential plane.

Aged↗
PubMed1996

[Structural analysis of the thickness of human dura mater with scanning electron microscopy].

INTRODUCTION: The only references to the thickness of the human dura mater, reporting its size at various levels, are now 50 years old. Our aim was to study its tridimensional structure with the aid of the scanning electron microscope. METHOD: The samples, which were taken 8-12 h after death from 4 human cadavers between 70 and 78 years old, were examined on 2 orthogonal planes (radial longitudinal and transversal). RESULTS: The architectural structure of the external membrane of the meninges was unusual. The dura mater is made up of elastic collagen fibers organized in successive parallel planes on the surface of the medulla. Each plane constitutes a unit which we will call a sub-laminae. The sub-laminae are found in groups of 8 to 12 that form larger units called laminae, which are between 4 and 5 microns thick. The full thickness of the dura mater at the level of the third lumbar vertebrate contains from 78 to 82 laminae which together measure 270 microns. CONCLUSION: The dura mater is made up of a large number of sublaminae that are concentrically parallel to the surface of the medulla. The fibers in general run in all directions and are oriented differently in each sub-lamina. The orientation of fibers that can be seen on the outer or epidural surface corresponds only to the fibers of the outermost lamina, which has a thickness of 78 to 82 microns. A needle that pierces the dura mater passes through some 700 to 800 sublaminae, each with its own particular distribution of fibers.

Aged↗
PubMed1996

[Iatrogenic spinal epidermoid tumors. A late complication of spinal puncture].

INTRODUCTION. Epidermoid tumors in the spinal canal are rare. Whether congenitally or iatrogenically caused, they form as the result of epidermal cells implanted within the spinal channel. Such implantation can occur during a variety of procedures and events such as bullet wounds, surgery, myelography or punctures for diagnosis, anesthesia or treatment. Although this complication is not discussed in books or journals on anesthesiology, we have found it mentioned in over 100 published cases reporting iatrogenically caused spinal epidermoid tumors. ETIOPATHOGENESIS. Iatrogenic epidermoid tumors of the spine derive from the implantation of epidermal tissue transported inside the spinal canal during lumbar punctures without guidance or with inadequate guidance. There is ample evidence that such tumors are iatrogenic. All cases occur in patients with a history of lumbar puncture. They are rarely associated with congenital anomalies. They are extramedullary. They tend to develop near sites of earlier lumbar puncture, usually near the conus medullaris and the cauda equina. Iatrogenic epidermoid tumors of the spine have been reproduced experimentally in two studies in which autologous skin fragments were implanted in the spinal canal. CLINICAL SIGNS. These tumors are well tolerated by patients for extended periods of time, ranging from 2 to 10 years. At the cauda equinus, tumors can grow slowly for long periods without signs of nerve compression. Symptoms are directly related to tumor size and site. All patients with tumors at the cauda equinus report severe pain radiating toward the roots of compressed nerves. Nuclear magnetic resonance makes it possible to detect the tumor without administration of intrathecal contrast. At present gadolinium-DTPA improves the image so that these tumors can be distinguished from other types. The prognosis for epidermoid tumors of the spine is good, as they are histologically benign. Treatment is always surgical. CONCLUSION. Although the causal relation between epidermoid spinal tumors and lumbar puncture is well documented, anesthesiologists are not sufficiently aware of this possible complication. Between 1977 and 1995, 28 new cases were published. We believe that a deeper understanding of such rare complications will show us how to prevent them while providing appropriate use of epidural and subarachnoid anesthesia.

Epidermal Cyst↗
PubMed1994

Spinal anaesthesia with 29 gauge Quincke point needles and post dural puncture headache in 2,378 patients.

Two thousand three hundred and seventy-eight spinal anaesthetics using a 29 G Quincke point needle were administered in a District Hospital between May 1983 and December 1991. The overall post dural puncture headache rate (PDPH) was 1.2% with a maximum of 2.5% in patients between age 30 and 39. PDPH was related to the experience of using 29 G needles (0.5% in consultants versus 2.0% in trainees, P < 0.05).

Adolescent↗
PubMed1988

Anatomical re-evaluation of lumbar dura mater with regard to postspinal headache. Effect of dural puncture.

The effects of puncture of fresh cadaver dura with 20-, 22-, 26- and 29-gauge needles were observed. A 'tin-lid' phenomenon, manifested with all needle sizes, was capable of sealing the resultant hole. The larger the needle, the larger the hole, while rotation of the needle bevel 90 degrees to the fibres altered the shape of the hole. Holes made in thicker parts of the dura tended to retract more rapidly than those in thinner areas.

Anesthesia, Spinal↗
PubMed1987

[Anesthetic data processing--the Bad Säckinger model].

A cost-effective computer program for district hospitals has been developed to process data from anesthetic charts. Apart from monthly and annual statistics relevant to clinical anesthesia and hospital administration, the described system allows free data handling of all material stored in the data base. The possibilities and limitations of electronic data processing are discussed.

Anesthesiology↗
PubMed1985

Comparison of the effect of continuous positive airway pressure and blowing bottles on functional residual capacity after abdominal surgery.

In two groups of comparable patients undergoing elective abdominal surgery, functional residual capacity (FRC) was measured preoperatively and on the first 2 days after surgery. One group was treated by regular application of continuous positive airway pressure (CPAP), the other group by bottle blowing (BB). In both groups there was a significant reduction of FRC on the first postoperative day. BB and CPAP increased FRC preoperatively by approximately 50%. Postoperative CPAP or BB increased FRC towards the preoperative value. However, 10 min after the treatment was stopped, FRC was not different from the pretreatment level. In 4 healthy subjects the resistive work of breathing produced by CPAP or BB was measured. Both treatments increased mainly expiratory and total resistive work of breathing. BB resulted in especially high expiratory and total resistive work. It is concluded that CPAP and BB increase temporarily the reduced FRC after abdominal surgery. CPAP was much better tolerated by the patients due to the lower resistive work of breathing.

Abdomen↗
PubMed1982

Epidural analgesia or mechanical ventilation for multiple Rib fractures?

A protocol for treating thoracic trauma is proposed. Severe pulmonary lesion with increased venous admixture (e.g. contusio, atelectasis, aspiration) is treated by mechanical ventilation. Rib fractures with minor pulmonary lesion and therefore with only moderately abnormal gas exchange but with remarkably reduced vital capacity (even with flail chest) are controlled by thoracic epidural analgesia following vital capacity, tidal volume and respiratory rate. If both a severe pulmonary lesion and serial rib fractures are present, the patient is ventilated for 2-3 days and then extubated to breath spontaneously with epidural analgesia. The indication for a mechanical ventilation or for spontaneous breathing with thoracic epidural analgesia is therefore deducted more from functional variables than from morphological facts. The course of a consecutive series of 283 patients is presented. 155 patients were treated with primary ventilation and 112 patients with primary epidural analgesia, while 16 patients could be managed with general analgesia. The duration of treatment morbidity and mortality show this protocol to be very useful.

Adult↗
PubMed1981

Respiratory assistance on surgical wards with continuous positive airway pressure (Turbo-PEEP-Weaner).

Based on our own experience, we introduce a new continuous positive airway pressure device. The patient can breathe continuously positive airway pressure through a tight face mask, and thus the postoperative reduction in functional residual capacity is counteracted. This is shown by the well-documented clinical course of a 62 year old man who had respiratory insufficiency after proximal selective vagotomy.

Humans↗
PubMed1980

[Thoracic epidural analgesic (TEA) or controlled ventilation in the treatment of patients with multiple rib fractures (author's transl)].

In the last seven years 283 trauma patients were treated for multiple rib fractures and/or flail chest. Primary management consisted of only morphine analgesia in 16 patients, TEA in 112 patients, and mechanical ventilation in 155 patients. The indication for mechanical ventilation was always associated injuries (cerebral contusion, para- and tetraplegia, aspiration, severe lung contusion) and not the instability of the thoracic cage.

Anesthesia, Epidural↗
PubMed1978

A rationale for epidural analgesia in the treatment of multiple rib fractures.

Thoracic epidural analgesia (EA) is described as an alternative to controlled ventilation in patients presenting with multiple rib fractures. Lung mechanics were especially studied in 6 patients selected from a total of 49. The average ICU stay for this group was 4.5 days (2-11) and the mean age 55.7 years. The EA group was compared with 51 patients primarily ventilated who had an average stay in the ICU of 9.8 days and a mean age of 44.7 years. Mean number of rib fractures of the ventilated group at 6.5 was almost equal to the mean of 6.8 in the EA group. There was a difference in the number of associated fractures, 98 in the ventilated group compared to 35 in the EA group. Severe pulmonary and cerebral contusion were the two most important factors in enforcing the need to ventilate. The success of the method is evidenced by the increase in functional residual capacity (FRC), dynamic lung compliance (Cdyn), vital capacity (VC), the decrease of airway resistance (R) and a significantly increase of PaO2 (p less than 0,001) for the EA group with a balanced fluid therapy. All this accounts for the clinical observation of diminishing paradoxical movement of the flail segment.

Adult↗