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Biomedical subjects

M Wenzel

Publications and source records attributed to M Wenzel.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Work of breathing in differentiation of various forms of sleep-related breathing disorders].

BACKGROUND: In contrast to the obstructive sleep apnoea syndrome (OSA) the obesity-hypoventilation syndrome (OHS) is characterised by persistent hypercapnia during the day and predominant hypoventilation during sleep. In this study we wanted to know whether work of breathing (WOB) in a sitting and supine position separates both groups. PATIENTS AND METHODS: OSA population: 20 men, 50.5 +/- 9.2 years, Body Mass Index (BMI: 54.1 +/- 6.9 kg/m2, pO2: 65.6 +/- 6.6 mmHg, pCO2: 40.6 +/- 3.1 mmHg, OHS-group: 14 patients, 13 men age: 53.1 +/- 9.3 years, BMI: 53.1 +/- 9.3 kg/m2, pO2: 51.8 +/- 10.5 mmHg, pCO2: 53.8 +/- 9.2 mmHg. The control group consisted of 10 normal weighted subjects. The intrathoracic pressures were assessed by an oesophageal catheter; at the same time, the minute ventilation (VE) and the breathing frequency (fb) were measured via a pneumotachygraph. The area under the pressure-volume loop was correlated to WOB. After reaching steady state VE, fb, and WOB were determined in sitting and supine position. RESULTS: In the OSA-group the apnoea index (AI) was 48.6 +/- 17.7/h and the respiratory disturbance index (RDI) was 66.3 +/- 19.4/h. The forced expiratory volume (FEV1) was 77.3 +/- 23% pred. and the vital capacity (VC) was 76.3 +/- 18.6% pred.; 7 out of 20 patients suffered from chronic bronchitis. In the OHS-group the AI was 21.5 +/- 19/h and the RDI 44.3 +/- 28.2/h. The majority of OHS patients had an airway obstruction (FEV1: 55.8 +/- 17.5% pred., VC: 58.8 +/- 12.8% pred.); 12 out of 14 patients suffered from chronic bronchitis. Compared to the OSA population WOB in the OHS group was significantly higher both in the sitting (0.67 +/- 0.28 J/I versus 1.04 +/- 0.32 J/I, p < 0.001) and supine positions (1.23 +/- 0.25 J/I versus 1.91 +/- 0.43 J/I, p < 0.001). Compared to the sitting position VE and fb did not change significantly in both groups lying supine. CONCLUSIONS: Compared to the OSA group at the same BMI the WOB of the OHS population was significantly increased in the sitting and supine position. The main reason for these findings may be the increased airway obstruction due to chronic bronchitis. Both populations did not change the breathing patterns during the different positions.

Adult↗
PubMed1997

[Nasal strips without effect on obstructive sleep apnea and snoring].

Recently a nose plaster (NP, Breathe-Right) has been increasingly used in the treatment of obstructive sleep apnoea (OSA) and snoring. Hence, we examined the use of the NP as a treatment of both OSA and snoring without OSA. The NP has a elastic spine that increases the diameter of the nostril and is thought to reduce the degree of OSA and snoring. According to the polysomnographic data two groups were differentiated: Group A (30 patients with OSA, apnoea index > 10/h, 26 men) and Group B (20 snorers, without OSA, 13 men). After the diagnostic polysomnography the efficacy of the NP was measured with a cardiorespiratory polygraph on the 2 following nights. In the group A the polygraphic data (apnoea index, time of apneas, desaturation index, time of desaturations, mean and nadir SaO2) were studied; in group B the snoring index (snoring events/hour) was measured. A questionnaire scored quality of sleeping, daytime condition and the quality of nose breathing. In neither group were the recorded polygraphic findings different with the NP although with the NP an improved nose breathing was scored in both groups. In group A 90% of the patients scored the daytime sleepiness unchanged and 10 of 30 patients described an improved quality of sleep. In group B there was no change in the frequency of snoring events with the NP. Neither the degree of OSA nor of snoring without OSA were changed by the NP, which can therefore not be considered a treatment of these conditions. However, the majority of the study population were impressed by the symptomatic improvement in nose breathing.

Dilatation↗
PubMed1997

[Changes in the time spent awake in obstructive sleep apnea and snoring--results of a pilot study].

Continuous positive airway pressure (CPAP) therapy reduces sleeping time per day and daytime sleepiness in obstructive sleep apnoea (OSA) and heavy snoring. Due to sleep fragmentation the OSA and heavy snoring are associated with a daytime sleepiness and increased necessity of sleep. In this pilot study the effect of CPAP-therapy on daytime sleepiness and sleep time during 24 hours were assessed in patients with OSA or heavy snoring (daytime sleepiness, none or slight apnoea with AHI < 10/h and benefit of CPAP). We studies 42 patients with OSA (AHI: 34.5 +/- 23.6) and 15 patients with heavy snoring: inclusion criteria: Patients with OSA (AHI > 10/h, ESS-Score > 8) and heavy snoring (AHI < 10/h, ESS-Score > 8) who were treated with nCPAP. Before and 2 months after initiation the CPAP-therapy all patients completed diary cards recording the sleeping time/day for 1 month; additionally they scored sleepiness using the Epworth sleepiness scale (ESS-score ranged from 0 to 24, the higher the score the worse the sleepiness) before and 2 months after initiation the CPAP-therapy. In the whole study population nCPAP-therapy reduced the sleeping time significantly by a mean period of 46 minutes per 24 hours (from 8.3 +/- 1.3 to 7.5 +/- 1.2 hours, p < 0.001) and improved the ESS score from 13.7 +/- 4.6 to 6.1 +/- 3.6 (p < 0.0001). In respect of the change of sleeping time/day and of the sleepiness score there was no significant difference between the OSA and heavy snoring group. With CPAP the AHI in OSA patients was reduced from 34.5 +/- 23.6/h to 3.2 +/- 3.2/h. Due to the improvement of sleep-related breathing disorders CPAP therapy reduced the mean sleeping time/day by approximately 10% and the daytime sleepiness score both in patients with OSA and heavy snoring compared to the pretreatment period.

Airway Obstruction↗
PubMed1996

[Satisfaction of cataract patients].

BACKGROUND: Most of the presentations concerning quality assurance following cataract surgery are based upon objective data, as it should be. But the success of an eye-clinic is not limited by such objective data, but on the contentment of the patients and the local colleagues, who direct the patients. Our aim in the following study is to find out, if there is a correlation between objective data and the contentment of cataract-patients. MATERIAL AND METHODS: 101 non-selected patients were asked about their contentment following cataract surgery and lens implantation. They were asked twice; first immediately after surgery and second two months after surgery. The subjective data of the patients were compared with objective data. RESULTS: 99% of the patients were content with the surgery, but only 88% were content with their visual acuity. There was no correlation between contentment of the patients and visual acuity. 13% of the patients reached a vision below 0.2. All but one said to have a good or moderate vision. 16% claimed to have poor or very poor vision, they all had a vision between 0.2 and 1.0. CONCLUSIONS: The ophthalmic surgeon must not be satisfied by his own good surgical results. In addition, he has to take care of the contentment of his patients. But it is even more dangerous, if the surgeon is proud because of his many content patients. Even if the patients are satisfied, he has to take care, if he really deserves the thanks of them.

Adult↗
PubMed1996

A school-based clinic for elementary schools in Phoenix, Arizona.

A community hospital, a school district, and a private pediatrician's office collaborated to ensure all children enrolled in five elementary schools had access to health care services. The school nurse at each school identified children needing health care services and obtained parental consent. The school nurse referred children to a nurse practitioner who visited one school each day. School nurses and space in the nurse's office were provided by the school district. The hospital provided a nurse practitioner as well as pharmacy, radiology, laboratory, and emergency department services. The pediatrician as medical director for the program provided vision, training, and community connections, and served as collaborating physician for the nurse practitioner.

Ambulatory Care Facilities↗
PubMed1995

Platelet aggregation inhibiting and anticoagulant effects of oligoamines, XXX: Absorption, organ distribution, and excretion of the oligoamine (+)-(S,S)-1,4-bis-[4-(3-iodo-4-methoxyphenyl)-butylamino]-butane-2,3-di ol and its metabolites.

The pharmacokinetic behaviour of the 131-iodine-labelled title compound 3* and its metabolites in mice was investigated. A two phase, 1st order elimination profile was observed. The second phase is very slow leaving about 35% of radioactivity in the mice even 100 h after i.v. injection, because of high affinity to liver and spleen, caused by strong binding of oligoamines to phospholipids of liver and blood cell membranes. The blood-brain-barrier is not passed. No deep compartments were observed. The doses necessary for antithrombotic effects in vivo were calculated from the blood levels to be 20.5-39.7 mumol/kg for a time interval of 1-6 h after administration.

Animals↗
PubMed1995

Distribution behaviour of 131-iodine labelled trans-N,N'-bis-(ethoxy-carbonyl)-N-[4-(3-iodo-4-methoxyphenyl)butyl]-N' -5- phenylpentyl)-1,4-cyclohexanedimethanamine.

The title compound 9, which is a prodrug, and its active metabolite 7 were labelled with 131I (7*/9*) to investigate their pharmacokinetic behaviour, including the distribution between stomach, gut, muscle, blood, lung, liver, kidney, adrenal gland, heart, and spleen. Four hours after oral administration of 7* to mice only 3% of the dose had been absorbed from the g.i. tract. After 24 h 54% of the radioactivity still is found the gut, predominantly in the small intestine. These results explain why 7, which is a potent antiplatelet drug in vitro, shows no antithrombotic effect in vivo. In contrast, the produg 9/9* is absorbed considerably, i.e. up to 50% in 4 h from the g.i. tract depending on the dose applied and the vehicle used. At doses in the micromolar range the absorption appears to be diffusion limited. The highest concentrations are found in the liver and the kidneys suggesting a first pass effect of 7 followed by renal excretion. From the blood levels achieved, the dose necessary for an antithrombotic effect has been calculated to be about 100 mg/kg. In summary, the N-ethoxycarbonyl derivatives of oligoamines appear to be suitable prodrugs for oral administration of oligoamines.

Animals↗
PubMed1995

[Increase in hypercapnia in exercise--an unloading strategy?].

BACKGROUND: Chronic hypercapnia seems to preserve the overloaded respiratory pump from manifest muscle failure. In order to get information about the regulation of the ventilation under exercise we investigated clinical stable hypercapnic patients. PATIENTS AND METHODS: Twenty-one patients (20 males, 53.7 +/- 13.2 years) with obesity-hypoventilation syndrome (8), chronic obstructive lung disease (4), scoliosis (3), myopathy (2) and post-Tbc (2) were examined. Ventilation parameters (fb, Vt, VO2), respiratory muscle strength (PImax, PEmax), arterial blood gases (pO2, pCO2), respiratory quotient (RQ) and lactate were measured at rest and at the end of 5 minutes of maximal bicycle exercise. The control group consisted of 10 healthy persons. RESULTS AND CONCLUSIONS: A significant augmentation of the pre-existing hypercapnia under exercise (reflecting hypoventilation in relation to the predicted value) was observed in all patients with chronically overloaded respiratory muscles. This mechanism seems to be wise because it protects the respiratory pump from failure.

Adult↗
PubMed1995

[Value of transtracheal oxygen insufflation in the weaning period after long-term ventilation].

BACKGROUND: In many cases, respiratory muscle failure is the reason for unsuccessful weaning attempts after long-term ventilation. Therapeutic measures must therefore be aimed at unloading the respiratory pump. In this present study we examined whether, in particular, the transtracheal O2-insufflation (TTO2) results in a change of breathing patterns and unloads the respiratory muscles. PATIENTS AND METHODS: We examined 6 patients (5 males, age 65.6 +/- 3.9 years, diagnosis: chronic obstructive lung disease), who received long-term mechanical ventilation in outward intensive care units. Baseline resting data (arterial blood gas analysis, the breathing frequency and the minute volume) were obtained with the patients breathing room air for 1 hour. After receiving TTO2 with a flow of 21/min for another 1-hour-period the measurements were repeated. RESULTS AND CONCLUSION: In our study we could show that the TTO2 leads to an impressive decrease in inspiratory work of breathing-relative to the minute ventilation by about 28%. Therefore TTO2 is of great importance in the weaning phase subsequent to prolonged mechanical ventilation due to the respiratory muscle failure.

Aged↗
PubMed1995

[Foreign body reaction after lens implantation. Correlation between visual acuity and density of giant cells].

In the early postoperative stage giant cells often appear on IOLs. Independent of this, a foreign-body reaction may start about 3 months after surgery from posterior synechia. Foreign-body reaction occur more frequently in diabetic patients or patients with glaucoma. In a prospective trial, we examined the surface of the IOLs from 115 patients with diabetes or glaucoma using specular microscopy. We compared the maximal density of the cells to visual acuity. One week and 1 month after surgery, the maximal density of giant cells was between 0 und 20/mm2; vision (median) was independent of the giant cell density in all groups between 20/25 and 20/30. Three months after surgery, the maximal density of giant cells was between 0 und 35/mm2; vision (median) was 20/25 in patients with no giant cells or cell densities up to 15/mm2. Seven patients had cell densities between 16 and 35/mm2; visual acuity (median) was 20/125. The difference was significance was (P < or = 0.05). Six months and 1 year later after surgery, the maximal density of giant cells was between 0 and 41/mm2; the vision (median) in patients with giant cell densities up to 15/mm2 was between 20/20 and 20/25. In five examinations the cell densities were found to be in the range of 16 to 40/mm2; visual acuity (median) was 20/80 in these cases. The difference is not significant (P < or = 0.05). A foreign-body reaction with more than 15 giant cells/mm2 is a rare complication of cataract surgery with lens implantation. Three months after surgery, this complication correlates with poor vision.

Aged↗
PubMed1995

[Epithelialization of porous biomaterials with isolated respiratory epithelial cells in vivo].

Extensive tracheal defects after prolonged assisted ventilation, trauma or large resections in tumor surgery are a challenge in plastic and reconstructive surgery. Defects which cannot be satisfactorily repaired reguine near of an alloplastic tracheal replacement. Previous experimental and clinical experiences in the development of an alloplastic tracheal prosthesis have demonstrated that the main cause for failure is the lack of an epithelial lining of luminal surfaces and inadequate biophysical properties of the prosthesis. With the use of a cell-seeding technique tested in vitro on biomaterials epithelialization of tracheal prostheses can be tested in vivo. In animal experiments isolated respiratory cells were seeded into implanted tubular prostheses of porous polyurethane or expanded polytetrafluorethylene. Light and scanning microscopic investigations then showed the tendency of epithelialization to occur on the luminal surfaces. Vigorous squamous epithelium cell layers that were single and (predominantly) multiple layers were found. Differentiated cilated or mucous cells were not detected in any case. The present results have shown that epithelialization of incorporated porous implants is possible. The realization of usable tracheal replacement for clinical practice must still be tested in further experiments.

Animals↗
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↗