Search PubMed⌕ Search

Biomedical subjects

M Wenzel

Publications and source records attributed to M Wenzel.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1991

[Prevention of cellular foreign body reactions to lens implants].

A heparin-surface-modified PMMA IOL has recently been developed in order to give the IOL a hydrophilic surface and to reduce postoperative inflammatory reactions in the eye. It is known that severe inflammation accompanies a tremendous increase in leucocytes in IOLs. A foreign-body reaction is characterized by the formation of histiocytic giant cells. The topical administration of corticosteroids, or the surface passivation of IOLs, cannot prevent a foreign-body reaction. Specular microscopy was used for in vivo investigation of cellular reaction in IOL surface of heparin-surface-modified lenses versus regular PMMA lenses. The double-masked and randomized study included 53 patients investigated 1 week and 1 month postoperatively. Small, round, and spindle-shaped cells were the cells most frequently observed after 1 week. These cells were identified in all cases. They were found in a higher density on the surface of the control lenses (43 cells/mm2) than on the heparin-surface-modified lenses (25 cells/mm2). Giant cells were found in two patients after 1 week; both of these patients belonged to the control group. Small, round, and spindle-shaped cells were also seen in all patients 1 month postoperatively. Again, they were found in a higher frequency on the control lenses (38 cells/mm2) than on the heparin-surface-modified lenses (13 cells/mm2). Giant cells were found in 18 patients 1 month postoperatively. They were found exclusively on the control lenses; the difference was significant (p less than 0.0001).

Follow-Up Studies↗
PubMed1991

An alternative to 'two-step' tuberculin skin testing for Southeast Asian refugees.

Previous studies report that Southeast Asian refugees demonstrate very high incidences of positive reactions to two-step tuberculin testing. In spite of these findings, fiscal restraints have limited the use of two-step testing in some of the centers that screen large numbers of these refugees. In this study, 101 Southeast Asian refugees were studied for their antigenic response to the tuberculin skin test. Forty-nine had positive reactions when the tuberculin skin test was read at 48 hours. Of the 52 refugees who showed a negative reaction at 48 hours, 22 had positive reactions when read a second time, three to five days later. The 28 refugees with negative reactions at both 48 hours and at five to seven days underwent two-step tuberculin testing. Only two of the 28 demonstrated positive reactions with two-step testing. Of the refugees with positive reactions at 48 hours, all but one continued to show positive reactions when the skin test was read a second time, at five to seven days. These findings suggest that a single tuberculin skin test, read at five to seven days, may provide a cost-effective alternative to two-step tuberculin testing for Southeast Asian refugees.

Adolescent↗
PubMed1990

Cellular reactions on heparin surface-modified versus regular PMMA lenses during the first postoperative month. A double-masked and randomized study using specular microphotography.

Specular microscopy was used for investigation of cellular reactions on the intraocular lens (IOL) anterior surface of Heparin surface-modified (HSM) versus regular polymethylmethacrylate (PMMA) lenses (Pharmacia types 700C versus 700B, respectively). The double-masked randomized study included 53 patients investigated at 1 and 4 weeks postoperatively. Giant cells were only found on control lenses and more frequently at 4 weeks. Small cells were found on both lens types, but in a higher frequency on the control lenses. The number of small cells decreased during the first 4 weeks on both the control and HSM lenses. However, those control lenses that had giant cells on their surface showed an increase in the number of small cells during the same time. The results of the current study show that HSM lenses give rise to less postoperative inflammatory cellular reactions than regular PMMA lenses.

Aged↗
PubMed1990

[Iritis following cataract operations. Historical retrospective with critical comments on a so-called "toxic lens" syndrome].

Postoperative inflammation is one of the oldest complications of cataract surgery. It was described by the Indian Susruta as early as 500 BC. Following the introduction of cataract extraction by Daviel in 1745, these operations attracted increasing interest. In 1786 de Wenzel distinguished two types of postoperative inflammation. In the dangerous type there was involvement of the entire eye and severe pain; in the benign type, which began in the first few postoperative days, the conjunctiva and lids were not involved, and even if hypopyon developed there was no severe pain. During the 19th century, the possible causes of the benign type of iritis were discussed, including infection, phacoanaphylaxis, trauma, toxicity of irrigation solutions etc. In the early days of implantation of intraocular lenses, from 1949 onward, postoperative inflammation was common. However, it was not until 1980 that the term "toxic lens syndrome" was introduced. The clinical descriptions do not differ much from other descriptions of benign iritis published during the last 200 years. Therefore, it does not seem that there is any great advantage to be gained by using this new term.

Cataract Extraction↗
PubMed1990

Increased concentrations of a circulating sodium pump inhibitor in essential hypertension and uraemia and its partial purification from haemofiltrate.

Patients with essential hypertension have 3.2 fold and patients with chronic uraemia 11.7 fold higher serum concentrations of endogenous digitalis-like activity than normotensives (76.3 +/- 9.3 nM). Upon haemodialysis this serum activity drops to almost normal values. A low molecular factor could be partially purified from 4000 l haemofiltrate.

Aged↗
PubMed1990

[Immunohistochemical studies of the human lens capsule].

In this study we made an attempt to localize components of the human lens capsule using immunohistochemical methods. Type IV collagen could be shown in all parts of the capsule in equal distribution. It could be found over the whole thickness of the lens capsule. By comparison, laminin could be detected only at the inner layer of the capsule. There was no difference concerning the contribution of these components between the anterior and the posterior capsule. No specific staining of collagen types I and III or of fibronectin could be found.

Collagen↗
PubMed1989

[Enoxacin concentrations in serum and in the wall of the colon during colorectal surgery].

For successful prophylaxis of postoperative infections in colorectal surgery the administered antibiotic must reach sufficiently high concentrations in plasma and gut wall. Therefore, in ten patients receiving 400 mg enoxacin orally about 2 h prior to operation (in addition to their routine perioperative intravenous prophylaxis with amoxicillin and clavulanic acid) concentrations of enoxacin were determined by HPLC in plasma (samples were taken at the beginning of operation, time of tissue sampling and each hour during the operation) and in gut wall. We found the following plasma concentrations (mean +/- S.D.): beginning of operation 2.53 ( +/- 1.07) mg/l, 1 h later 2.08 ( +/- 0.82) mg/l, 2 h later 1.60 ( +/- 0.65) mg/l. At the time of tissue sampling (on an average 185 min after the enoxacin dose) the plasma concentration was 2.27 ( +/- 1.02) mg/l, the gut wall concentration was 3.74 ( +/- 1.58) mg/kg, the ratio between the two concentrations was 1.70 ( +/- 0.27). It seems warranted to study orally administered enoxacin (in combination with an antibiotic against anaerobes) in prophylaxis of infections after colorectal surgery.

Aged↗