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Biomedical subjects

M Wenzel

Publications and source records attributed to M Wenzel.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Decompression of the optic nerve after fractures of the rhino-basal skull with computer-assisted surgery].

Referring to 22 cases of surgery after frontobasal fractures of different origin with loss of vision, the surgical procedure is discussed with special consideration of the approach, technique and timing of the operation. We conclude that the external rhinological approach through the ethmoid sinus is the best and easiest access in cases of loss of vision with verified fracture or haematoma. A number of patients were operated using CAS (Computer Assisted Surgery)-Systems, a CT-based tool for three-dimensional orientation. It proved to be very useful for the surgeon, saving time and reducing the risk of additional damage. According to our experience and the results of other authors we believe that surgical intervention should be performed as early as possible.

Blindness↗
PubMed1994

[Autologous transplantation of nasal mucosa after severe chemical and thermal eye burns].

BACKGROUND: Extensive conjunctival scarring is common after severe chemical and thermal eye burns. There is often not enough healthy conjunctiva from the other eye available to correct the symblepharons, therefore other autologous tissues have to be transplanted. PATIENTS AND METHODS: From February 1992 until March 1993 13 patients were treated with free nasal mucosal grafts from the inferior turbinates for reconstruction of the fornices. The newly created deep fornices were secured by a silicone band. In 3 patients an Illig plastic shell was used additionally. The surgical treatment was supplemented with an intensive treatment with topical corticosteroids to decrease the inflammatory reaction. RESULTS: The patients were followed for an average of 7-18 months. The interval between the accident and the transplantation ranged from 2-26 months. In 10 patients a reconstruction of the fornices was achieved. In all patients, however, some slight scars could be observed. Postoperative Schirmertest was markedly improved. These results encourage us to plan a penetrating keratoplasty in 7 cases. 3 patients showed a recurrence of the symblepharon 2 months after the transplantation. CONCLUSION: The nasal mucosa graft material is best suited for repair of extensive symblepharon. The advantages of this tissue are the availability of large pieces of mucosa and the transplantation of intraepithelial goblet-cells. Long-term effects are the improvement and stabilisation of the tear film.

Adolescent↗
PubMed1994

[Why is the gray cataract called "star"?].

The adjective "starblind" has its origin in the 8th century. It describes the disease of eyes which are blind from cataract. This definition can be derived from the ancient Greek medicine and is the definition for a "starre" (which means inert) effusion behind the pupil. Martin Luther introduces the subject "Star" as a synonym for blindness. In the 18th century some linguists supposed this subject could be deducted from "starr blicken" (which means "to look motionless"). Even until today this misleading meaning is widespread although standard literature of linguistics as well as standard literature of the history of ophthalmology refer to the original meaning of this word.

Blindness↗
PubMed1994

A case of mild ocular manifestations in pregnancy induced hypertension with HELLP syndrome.

There is a correlation between the degree of retinal changes and the severity of pregnancy induced hypertension. This correlation does not hold true for a subgroup of these patients with hemolysis, elevated liver enzymes and a low platelet count. This array of findings has been termed HELLP syndrome by Weinstein (1982) and may be present although the clinical picture of severe preeclampsia is absent. Pregnancies complicated by HELLP syndrome are associated with poor maternal and fetal outcome. We report a case in which minor ocular signs led to the diagnosis of a HELLP syndrome. Ophthalmologists should be aware of this rare complication of pregnancy.

Adult↗
PubMed1994

[Extraction of orbital foreign bodies using a new kind of image processing system].

We present a new localization system in orbital surgery. The procedure is based on the linkage of two methods. A preoperative thin-layer CT scan is taken and the image data are fed into a high-capacity computer which computes a three-dimensional model of the orbit. Intraoperatively, the volume model of the skull is linked to a mechanical arm for position measurement. Surgical instruments can be mounted to this arm. The computer then projects the position of the instrument into the volume model of the orbit, so that the surgeon can follow the movements of his instruments on the monitor. The surgeon has a means of checking position that comes close to constant intraoperative CT monitoring. Thereby the surgeon is able to localize even small foreign bodies without extensive explorations. We present six patients in whom orbital foreign bodies had to be extracted during the past 5 years. A 44-year-old man had an iron foreign body; the external wound was treated surgically elsewhere. Two patients (25 and 22 years old) had glass foreign bodies; in one of them the splinters were not seen using conventional X-ray. Choosing the exact level with the Hounsfield window, the foreign bodies could be demonstrated on the monitor. In three patients with orbital fractures and compression of the optic nerve, dislocated bone splinters were extracted. The localization of those splinters was easy using the imaging system, but would have been rather difficult by other means.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Biocompatibility of silicone intraocular lenses].

BACKGROUND: In order to the biocompatibility of silicone intraocular lenses, which is described contradictory in literature, we compared IOLs made of silicone caoutchouc and PMMA-IOLs with regards to the presence of macrophages (i.e. giant cells or spindle-shaped cells) in a prospective, randomized study. PATIENTS AND METHODS: Totally 125 patients were examined 2 months post-operatively with the slitlamp in the refractive zone. The single-piece PMMA-IOLs with an open haptic used in this study had a 6 mm optical zone and a total diameter of 11 mm; the silicone-IOLs were disc-shaped lenses with a total diameter of 9.75 mm and an optical zone of 6 or 5.5 mm, resp. RESULTS: Giant cells were observed with 16% of PMMA-lenses and 19% of the silicone-lenses. The maximal density of the giant cells on the PMMA-lenses at the median was 3/mm2 compared to 2/mm2 on the silicone IOLs. Small and spindle-shaped cells were found in 54% of the PMMA-IOLs and 46% of the silicone-lenses. The maximal cell density at the median was 10/mm2 with both lens types. CONCLUSIONS: The differences between the two lens materials are statistically non-significant. Thus, silicone caoutchouc and PMMA possess a comparable biocompatibility when used as material for intraocular lenses.

Aged↗
PubMed1993

Time course of lectin and storage protein biosynthesis in developing pea (Pisum sativum) seeds.

Lectins and storage proteins from pea (Pisum sativum) and other Leguminosae seeds interact in vitro. In order to evaluate whether this relationship may be important also in vivo, the time course of biosynthesis of these proteins in developing pea seeds was followed. The proteins appear in the following temporal order: vicilin-lectin-convicilin-legumin. The time course of protein synthesis was also followed by the subcellular morphological changes occurring simultaneously. The appearance of vicilin coincides with the formation of regularly shaped protein globules within the vacuole. Immediately after the start of lectin synthesis, these globules flatten and begin to adhere to the inner membrane surface of the vacuole. Legumin appears at a time when the vacuoles already have largely disappeared in favour of smaller vesicles which eventually develop into protein bodies. These results together with previous findings are consistent with the view that one of the biological functions of the lectin may consist in serving as a link between vicilin and the inner face of the vacuole membrane.

Antibodies, Monoclonal↗
PubMed1993

Experiences with ACE inhibitors early after acute myocardial infarction. Rationale and design of the German Multicenter Study on the Effects of Captopril on Cardiopulmonary Exercise parameters post myocardial infarction (ECCE).

Left ventricular damage by necrosis of myocardial tissue can lead to compromise of left ventricular function, to left ventricular volume increase and ultimately to development of heart failure. This sequence in the pathophysiology has been shown to be blunted by ACE inhibitors. Volume increase, however, can also be helpful in restoring stroke volume and ameliorate elevation of filling pressures. Furthermore, very early institution of ACE inhibition has failed to improve short-term mortality after myocardial infarction in one large trial. The aim of the ECCE trial therefore is, to investigate the early effects of the ACE inhibitor captopril on compromise of exercise capacity, thought to be a first measurable sign of developing heart failure. The ECCE trial is a randomized, seven-center investigation, studying the effects of ACE inhibition on oxygen uptake in a double blind, placebo controlled design in a group of 204 patients. Sample size was calculated on the basis of a pilot trial. The study design and first not unblinded data of 104 patients are presented. The population consists of predominantly male patients with mostly first myocardial infarction. They were admitted to hospital within five hours of onset of chest pain. End-diastolic volumes were normal, but ejection fraction was moderately compromised. ACE inhibition was started after the first day, but within 72 hours of onset of chest pain. After four and after twelve weeks, oxygen uptake was considerably below expected values and one third of the patients had severe compromise of exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[In vitro contractility behavior of portal veins in normal rats and in rats with liver cirrhosis--effect of calcium antagonists and octreotide].

According to Poiseuille's law portal pressure is inversely related to r4. Thus, minor changes in radius dramatically influence intravascular pressure. Since the radius is actively regulated by contraction, this study elucidates in vitro contractility patterns of portal veins from healthy and liver cirrhotic rats. The results demonstrate that contractility amplitudes of portal veins from cirrhotic rats are increased in comparison to healthy animals. Calcium antagonists reduce amplitude and motility both in cirrhotic and healthy rats to the same degree. The same holds true for octreotide but significantly more in the cirrhotic group. Obviously, the maintenance of portal hypertension is supported by an active element of the portal vein, which can be controlled in vitro.

Animals↗
PubMed1993

Computer-assisted orbital surgery.

In orbital surgery, deep lesions must be operated on through extremely small approaches. We developed a method (Computer Assisted Surgery or CAS) designed to achieve safer and more precise surgery by providing highly accurate intraoperative information regarding the location of the surgical instrument. The device involved consists of a high-capacity computer that processes computed tomographic (CT) data in real time, connected to a mechanical measuring arm attached to the surgical instrument. From the CT data, the computer calculates a three-dimensional reconstruction and displays the tip of the instrument as a reticle in this model. Using the CAS system, the surgeon is continuously apprised of the precise position of the surgical instrument vis-a-vis all relevant anatomical structures. We have used CAS successfully in 21 cases of orbital surgery. We have found the system especially useful in dealing with deep-seated tumors, either for biopsy or surgery; in performing orbital and optic nerve decompression; in localizing deep-seated foreign bodies; and in all cases of impaired orientation due to severe bleeding, tumor-destroyed landmarks, or preoperated anatomy. Although the number of patients is too small to yield statistically significant data allowing a comparison of patient outcomes with and without using the system, we have just begun a large prospective clinical trial designed to provide such data.

Adolescent↗
PubMed1993

The influence of military low-altitude flight noise on the inner ear of the guinea pig. Part II: Scanning electron micrographs.

Guinea pigs were exposed once to MLAF noise (126 dB(A), 75 dB/s) and 12 cochleae were prepared for scanning electron microscopy 2 to 3 weeks after exposure. Qualitative analysis of the cilia of the outer hair cells revealed the types of damage already described in literature. The spatial distribution of cilia damage, however, differed essentially from the well known pattern: the damage was more or less pancochlear, beginning in the basal turn and increasing in frequency and severeness of damage till the end of the third turn. The most severe damage was visible in the outer row of the outer hair cells. This special pattern of cilia damage indicates that MLAF noise causes a different type of damage than the types described in literature. More studies are needed.

Aerospace Medicine↗
PubMed1993

[A new procedure for removal of foreign bodies in the area of the head].

Identification and extraction of penetrating cranial foreign bodies can cause problems in some cases. Small fragments localized deep in the orbit or cerebrum can be especially hard to detect. Severe bleeding and traumatized anatomy can make orientation difficult. We used a new localizing device, computer-assisted surgery (CAS), to good effect in six such cases. CAS is a localizing technique designed to assist the head surgeon during surgery, providing real-time position information. The method is based upon a three-dimensional volume model of the patient's skull generated by preceding computed tomography imaging procedures (CT or MRI). Intraoperative correlation of a 3D-model and the patient's skull allows for real-time position display of a surgical instrument on the monitor screen. Thereby the surgeon is able to localize even small foreign bodies without extensive exploration. In the case of multiple foreign bodies the surgeon calls up a simple documentation facility recording which of the visible fragments have already been extracted. We successfully used the system for extraction of orbital foreign bodies in four and intracerebral foreign bodies in two cases. In a 4-year-old child with gunshot injury the bullet was located in the precentral region and was easily extracted with the CAS system. In a 21-year-old man 39 glass fragments were extracted from the left orbit. In a 36-year-old man a bone fragment was dislocated to the apex of the orbit directly under the optic nerve. Location and extraction were achieved without damage to the orbital structures with the help of the CAS system.

Adult↗
PubMed1992

[Spiritual care].

Explore the source record for details and available documents.

Christianity↗
PubMed1992

Electrophysiological and morphological changes in rabbit retina after exposure to the light of the operating microscope.

Healthy adult rabbit eyes were exposed to up to 4 h of continuous illumination with moderate light intensity, as is produced by the lamp of an ophthalmic operating microscope. Electroretinograms were recorded before and after the long period of illumination. The depression of the waves in the electroretinograms observed just following light exposure recovered within 1 h to normal values. Electron microscopy of the retina revealed changes within the cells of the pigment epithelium. These results are discussed in view of their clinical implications in human patients.

Animals↗
PubMed1992

[Value of corticosteroids in after-care of patients after cataract extraction and lens implantation].

In two double-blind controlled trials the anti-inflammatory effects of dexamethasone were examined in post-cataract extraction eyes after lens implantation in 321 patients. In the first trial, 103 patients were included. 49 eyes received eye-drops with 0.1% dexamethasone and antibiotics, the control-group of 54 eyes received the same antibiotics without any steroids. The follow-up was 2 months. In the case of unexpected complications, the patients dropped out. This was the case in 48% of the steroid-group and in 79% of the control-group. The main reason for this statistically significant difference were inflammatory complications in the control-group, which are difficult to quantify. The incidence of fibrinous reactions was not significantly different in the two groups, probably because of small numbers. In the second trial, we looked for fibrinous reactions. The follow-up was 3 weeks, 218 patients participated. They were divided into three groups: 71 patients received eyedrops with 0.1% dexamethasone 4x daily, 77 patients received the same drops 4x daily up to the fifth postoperative day, from then on 1x daily. 70 patients received the same drops 1x daily. A mild fibrinous reaction was seen in 10% of the high-dose-group, in 6% of the medium-dose-group and in 21% of the low-dose-group. Only the difference between the last two groups is statistically significant. We conclude that the therapy with corticosteroids after cataract extraction and lens implantation may be reduced early in the postoperative course.

Adult↗
PubMed1991

AGN 190383, a novel phospholipase inhibitor with topical anti-inflammatory activity.

AGN 190383 is a 5-hydroxy-2(5H)-furanone ring analog of the marine natural product manoalide. When applied topically, AGN 190383 inhibits phorbol ester induced mouse ear edema. It is a potent inhibitor of bee venom phospholipase A2 and blocks the release of arachidonic acid from calcium ionophore A23187 stimulated human neutrophils. AGN 190383 also inhibits both hormone-operated and depolarization-dependent calcium mobilization in GH3 cells, as well as fMLP stimulated increases in free cytosolic calcium in human PMNs. Furthermore, it is also able to block the release of the neutral protease elastase from stimulated neutrophils. The effects of AGN 190383 on arachidonic acid metabolism and leukocyte function may account, in part, for its anti-inflammatory activity in vivo.

Administration, Topical↗
PubMed1991

Aortocoronary vascular prosthesis made of siliconized homologous vein or bovine sacral artery.

The purpose of our study was to develop and prepare aortocoronary prostheses, test them experimentally in multivascular and coronary reoperations in case of missing autologous grafts and to use them for shunt operations in cardiac surgery. Human vein or bovine sacral artery were used for preparing aortocoronary prostheses. As for metrics of 9-14 Charr. and a length of 20-30 cm were obtained. Aortocoronary prostheses were preformed according to the coronary configuration for left descending artery, circumflex artery and right coronary artery. Aortocoronary prostheses meet the conditions of desantigenicity, sterility, athrombogenicity, tightness and high tensile strength, tear propagation strength, bursting pressure and shrinkage temperature. Experimental testing was performed in dogs in aortofemoral and aortocoronary positions. Infections did not occur. The healing process and structural changes of aortocoronary vascular prostheses (grafts) were examined histologically and evaluated by means of scanning electron microscopic examinations. Athrombogenicity and healing-in without inflammation and calcification were proved.

Animals↗