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Biomedical subjects

M Sager

Publications and source records attributed to M Sager.

At least 19 recordsLinked to original sources
PubMed2001

The effect of tibial lengthening using the Ilizarov method on the cartilage and the menisci of the knee joint.

In order to investigate possible acute damage to the knee joint cartilage and the menisci during tibial lengthening, sixteen young beagle dogs underwent 30% lengthening of the right tibia of 2.5 cm by callus distraction at a distraction rate of twice 0.5 mm per day. A further four dogs comprised the control group with fixator and osteotomy but without lengthening. After a distraction period of 25 days half the dogs were killed (group A) while the other half (eight dogs with limb lengthening and two dogs without) were killed after a further period of 25 days (group B). At the end of the study, the menisci were removed together with three cartilage-bone cylinders from both femoral condyles from the weight-bearing zones as well as from the corresponding tibial condyles. Serial sections from the menisci were stained with haematoxylin and eosin (H&E) and Elastica van Gieson. Sections of the cartilage-bone cylinders were stained with H&E and safranin-O. Cartilage thickness was measured and the glycosaminoglycan content of the joint cartilage was determined using microspectrophotometry. None of the histological preparations obtained from the untreated and distracted sides showed any signs of damage to the cartilage or to the menisci. There were no significant differences between cartilage thickness and proteoglycan content of the untreated side and the lengthened side. Thus, tibial lengthening using the llizarov method does not appear to cause acute damage to the cartilage of the knee joint or to the menisci.

Animals↗
PubMed2001

The effects of a collaborative model of primary care on the mortality and hospital use of community-dwelling older adults.

BACKGROUND: This study evaluates the ability of a model of collaborative primary care practice to reduce mortality and hospital use in community-dwelling elderly persons. METHODS: Four rural and four urban clinic sites in east central Illinois were randomized to form treatment and comparison clinics from which patients were enrolled and followed prospectively for 2 years. Patients from the practices of participating physicians were eligible if they were aged 65 and older, were living in the community, and had at least one risk factor as determined prior to the study. Medicare hospital data were obtained from the Health Care Financing Administration. Demographic and health status measures were obtained by telephone interview every 12 months throughout the study. RESULTS: The treatment group experienced a 49% reduction in all-cause mortality during the second year of the study (odds ratio, 0.51, 95% confidence interval, 0.29-0.91, p = .02). There were no significant differences between treatment and comparison patients in percentage of persons hospitalized, hospital length of stay, or Medicare payments. Although measures of health status indicated that the treatment group was significantly sicker at baseline at the end of 1 year, these differences disappeared by the end of 2 years. CONCLUSIONS: The collaborative primary care model evaluated in this study significantly reduced mortality in the second year, without increasing hospital use. These findings suggest that a collaborative primary care team that enhances primary care practice can result in better patient outcomes.

Aged↗
PubMed2000

Temporal association between hospitalization and rate of falls after discharge.

BACKGROUND: Evidence suggests that acute illness and hospitalization may increase the risk for falls. OBJECTIVE: To evaluate the rate of falls, and associated risk factors, for 90 days following hospital discharge. METHODS: We consecutively enrolled 311 patients, aged 65 years and older, discharged from the hospital after an acute medical illness and receiving home-nursing services. Patients were assessed within 5 days of discharge for prehospital and current functioning by self-report, and balance, vision, cognition, and delirium by objective measures. Patients were followed up weekly for 13 weeks for falls, injuries, and health care use. RESULTS: The rate of falls was significantly higher in the first 2 weeks after hospitalization (8.0 per 1000 person-days) compared with 3 months later (1.7 per 1000 person-days) (P =.002). Fall-related injuries accounted for 15% of all hospitalizations in the first month after discharge. Independent prehospital risk factors significantly associated with falls included dependency in activities of daily living, use of a standard walker, 2 or more falls, and more hospitalizations in the year prior. Posthospital risk factors included use of a tertiary amine tricyclic antidepressant, probable delirium, and poorer balance, while use of a cane was protective. CONCLUSIONS: The rate of falls is substantially increased in the first month after medical hospitalization, and is an important cause of injury and morbidity. Posthospital risk factors may be potentially modifiable. Efforts to assess and modify risk factors should be integral to the hospital and posthospital care of older adults (those aged >/=65 years).

Accidental Falls↗
PubMed2000

Electromyographically evident changes in skeletal muscles during tibial lengthening in dogs using the Ilizarov method.

Twenty-four beagle dogs underwent a lower leg lengthening on the right side of 2.5 cm at a distraction rate of 2 times 0.5 mm per day using a circular fixator system. After a latency phase of 5 days and a distraction phase of 25 days, 12 dogs (30-day dogs) underwent electromyography (EMG) of the gastrocnemius muscle on the lengthened and on the control side. The remaining half of the dogs underwent EMG after a consolidation phase of 25 days following the end of distraction (55-day dogs). During every EMG, at least 20 different muscle potentials were analyzed, and the duration, amplitude, and number of phases were determined of each individual potential. The 30-day dogs had significantly longer potential phases on the lengthened side and insignificantly smaller amplitudes compared with the control side. Furthermore, we observed a slightly larger number of polyphasic potentials on the distraction side. In the 55-day dogs, no significant differences were observed in the various parameters between the lengthened and the control side. Comparing 30- and 55-day dogs, the duration of the potentials on the distraction side was not significantly shorter in the 55-day dogs, and the amplitude significantly higher. These findings could indicate combined neurogenous and myopathic alterations of the muscles during the early distraction phase which will be compensated during the later distraction period and the consolidation phase by reparative and reinnervation processes, leaving no lasting functional damage.

Action Potentials↗
PubMed1998

The impact of vasoactive substances on intraosseous pressure and blood flow alterations in the femoral head: a study based on magnetic resonance imaging.

In beagle dogs, the alterations of intraosseous pressure and blood supply in the femoral head that result from the administration of vasoactive substances were examined, and the changes were documented by magnetic resonance imaging (MRI). Vasoactive substance were infused into the medial and lateral circumflex femoral arteries of 12 beagle dogs. All infusions were done under standardised conditions with simultaneous measurements of venous blood flow and intraosseous pressure distribution in the proximal femur. The drugs were infused in three cycles of 30 min each separated by 30 min recovery periods, followed by MRI examination at the end of each experiment. At an intraosseous pressure of 14.3 (+/- 4.2) mmHg in the femoral head epiphysis (I), 11.6 (+/- 2.7) mmHg in the greater trochanter (II) and 9.3 (+/- 3.2) mmHg in the femoral shaft (III), a baseline flow of 96.2 (+/- 18.8, n = 12) ml/min was measured in the femoral vein. After infusing bradykinin at a concentration of 10(-6) moles, which is commonly known to lead to cerebral and subcutaneous oedema formation by vessel dilatation, the intraosseous pressure increased to (I): 49.1 (+/- 6.2) mmHg, (II): 42.5 (+/- 5.8) mmHg and (III): 38.3 (+/- 7.1) mmHg in the three measured femoral areas (n = 3). After the bradykinin injection, femoral vein flow increased to a peak value of 238.4 (+/- 43.4) ml/min and then dropped to 62.3 (+/- 14.2) ml/min after discontinuation of the bradykinin infusion. In a second and third series of tests, hyperosmolar (20% NaCl) and hypo-osmolar (distilled water) solutions were applied, also resulting in increased but lower mean intraosseous pressure values (17.3 +/- 4.1 and 25.7 +/- 5.1 ml/min, respectively) in all regions. When administering bradykinin, MRI scans taken immediately after completion of the experiment showed substantial oedema in the femoral muscular system, but without any changes of osseous signals in T1- or short time inversion recovery (STIR)-weighted images, nor did any changes occur when solutions of 20% NaCl or distilled H2O were injected. The results of our experiments demonstrate that acute increases of intraosseous pressure do not cause MRI signal alterations. We therefore conclude that in addition to the described pressure increase, other intraosseous alterations must occur to lead to the detectable signal changes found among patients with diagnosed femoral head necrosis. Finally, the short time period between the rise in intraosseous pressure and performing a conventional MRI may be one reason for missing the development of an intraosseous oedema. On the other hand, conventional MRI might have additional disadvantages for detecting intraosseous fluid compared with a dynamic imaging modality.

Animals↗
PubMed1998

Proprioception of the cruciate ligaments: receptor mapping in an animal model.

Ten anterior and posterior cruciate ligaments (ACL and PCL) harvested from adult sheep were investigated under light microscopy for data on the frequency and localisation of neural structures. Serial sections of 25 microns thickness were stained with a modified gold chloride technique. Receptors were classified according to their histological structure. Topographic distribution and frequency within the ligament texture were determined with the help of computerized image analysis. Three distinct neural structures could be identified: Ruffini endings, Ruffini corpuscles of the Golgi tendon organ-like type and Pacinian corpuscles. Golgi tendon organs were not found. In total, 274 and 238 neural structures were present in the 10 ACL and 10 PCL, respectively. Pacinian receptors were the most common structures, with a mean frequency of 13.6 +/- 5.3 (ACL) and 12.4 +/- 5.1 (PCL), followed by Ruffini endings with 8.9 +/- 3.2 (ACL) and 7.8 +/- 2.9 (PCL), whereas Ruffini corpuscles had the lowest frequency with a mean value of 4.9 +/- 2.1 (ACL) and 3.4 +/- 1.1 (PCL). The majority of the neural structures were located in the subsynovial sheath or closely associated with endotenon structures. The tibial and femoral insertion areas had a significantly increased receptor density compared with the midpart of the ACL and PCL (P < 0.001), where only 19.3% and 23.7% of the receptors were located. These results emphasise the complex sensory structure of the cruciate ligaments and provide a valid morphological basis for further neurophysiological investigations.

Animals↗
PubMed1998

Platelet cold agglutinins: a flow cytometric analysis.

Spontaneous EDTA-independent cold platelet agglutination is a rare phenomenon that produces pseudothrombocytopenia when blood samples are analyzed in automated cell counters. We report a case of platelet cold agglutinins and an analysis by flow cytometry. A 49 year old woman presented with abnormal vaginal bleed secondary to uterine fibroids. Platelet clumping was observed in blood samples taken in EDTA-, heparin- and citrate-containing tubes. In flow cytometric tests, patient serum agglutinated 16% of normal platelets at 22 degrees C, and 7% of platelets after incubation at 37 degrees C; in contrast, 3% and < 1% of platelets were agglutinated at 22 and 37 degrees C, respectively, after incubation with normal serum. Minimal agglutination (< 10%) was observed with patient serum at a titre of 1:5 or at temperatures > 30 degrees C. After incubation at 4 degrees C, IgM antibody and C3 were increased on the patient's platelets; no significant amount of IgM or C3 was detected on normal platelets. The specificity of the platelet cold agglutinin was determined by competitive inhibition by monoclonal anti-CD41(GPIIbIIIa). Before the addition of monoclonal antibody, patient's serum agglutinated 16% of normal platelets at 22 degrees C; after addition of anti-CD41 only 2% of the platelets were agglutinated. This blocking effect was not observed with anti-CD42. The patient's platelets functioned normally as determined by CD62 and CD63 expression in response to thrombin, normal platelet aggregation in response to collagen, ADP, and ristocetin, and a normal template bleeding time. In summary, platelet agglutination by a platelet cold agglutinin was quantitated by flow cytometry, the responsible antibody was characterized as a low titre IgM with minimal activity > 30 degrees C, and competitive binding studies supported the GPIIbIIIa complex as the binding site for the antibody. Since the antibody did not affect platelet function, we believe that these patients will not suffer complications from their platelet cold agglutinin, but it could pose a problem under circumstances such as cardiac surgery with hypothermia.

Adenosine Diphosphate↗
PubMed1998

Adverse drug events in hospitalized elderly.

BACKGROUND: The study objectives were (a) to describe the occurrence, types, and preventability of adverse drug events (ADEs) in hospitalized patients 70 years of age and older; (b) to examine the association between potential risk factors and ADEs; and (c) to examine the relationship of an ADE occurrence and hospital length of stay (LOS) and functional decline. METHOD: Consecutive general medical admissions (n = 157) of community-dwelling persons were prospectively monitored daily for ADE occurrence. Admission assessment included demographic factors, cognition, preadmission medication use, and functional status. Discharge assessment included functional status. LOS, discharge diagnoses, and medication use during the hospitalization. RESULTS: Twenty-three patients (14.6%) experienced 28 probable ADEs, of which 54.2% (13/24) were judged to be potentially preventable. Patients experiencing an ADE had a significantly lower mean Mini-Mental State Examination score (23.6 +/- 4.3 vs 25.5 +/- 3.6, p = .039) and were prescribed significantly more new inpatient medications (4.0 +/- 2.3 vs 2.6 +/- 1.7, p = .01) compared to non-ADE patients. Age, gender, functional status prior to admission, percent with more than four active diagnoses, or number of preadmission medications were not associated with ADE status. Upon discharge, 50.0% of ADE patients experienced a decline in one or more activities of daily living (ADLs), compared with 24.1% of non-ADE patients (p = .017). ADE patients had a longer LOS (8.7 +/- 4.9 vs 6.6 +/- 3.0 days, p = .022) compared to non-ADE patients. CONCLUSIONS: ADEs were associated with number of new inpatient medications and admission cognitive status, but not demographic, disease, or physical function variables. Patients experiencing an ADE were more likely to experience a longer LOS and to decline in ADL function. ADEs may be one factor contributing to functional decline during hospitalization. Future research in this area should include larger samples and multivariable analyses controlling for potential confounders.

Activities of Daily Living↗
PubMed1996

Proprioceptive mechanisms in the cruciate ligaments: an electromyographic study on reflex activity in the thigh muscles.

The hypothesis of a proprioceptive mechanism arising from mechanoreceptors in the cruciate ligaments and with efferences to the thigh muscles is investigated in an animal model. Electromyographic (EMG) studies of the quadriceps and hamstrings muscles were performed in six sheep anesthetized by intravenous injection of chloralose on applying static and dynamic shear forces to isolated fascicle bundles in the anterior (ACL) and posterior (PCL) cruciate ligaments at 200 to 500 N and 50 to 200 N/sec, respectively. With the help of an external fixator, the knee joint position was varied at 25 to 150 degrees. The relative preload of the anteromedial and posterolateral fascicles in the ACL and the anterior and posterior fascicles in the PCL induced by variation of the joint angle was measured with the help of strain gages. By static and dynamic loading of the anteromedial group of the ACL, EMG activity in the hamstrings increases significantly to 159 +/- 22 and 257 +/- 46 microV seconds, respectively (p < 0.001), with a simultaneous suppression of the quadriceps activity. Static and dynamic loading of the posterolateral ACL group results in a significant excitation of the quadriceps with mean potentials of 142 +/- 29 and 173 +/- 23 microV seconds, respectively (p < 0.001). Mechanical shear applied both to the anterior and posterior fascicles of the PCL induces a significant activation of the ipsilateral quadriceps muscles with a simultaneous inhibition of the hamstrings (p < 0.001). The quality of mechanical loading, i.e., static or dynamic shear, determines the degree of muscular recruitment significantly (p < 0.01). The joint angle contributes to a modulation in the quantitative EMG excitation. Linear regression analysis of the integrated EMG potential values and the amount of passive preload induced by the respective joint position results in a close correlation (r = + 0.78 to + 0.86). The results lead to the conclusion that a proprioceptive mechanism exists that arises from the cruciate ligaments and influences the tone in the thigh muscles. The degree of muscle excitation on mechanical ligament loading is modulated by the amount of preload in the ACL and PCL and the quality of load applied.

Animals↗
PubMed1994

Hyperthermic isolated limb perfusion with cis-diamminedichloro-platinum. II. An experimental study in dogs with a balloon-occlusion technique for repeated high-dose treatment.

Isolated organ perfusion is attractive for regional high-dose chemotherapy because of its advantage to reduce whole body toxicity. Intraoperative hyperthermic isolated perfusion procedures involving a heart-lung machine have been developed, but repeated treatments carry a high risk of vessel and tissue damage. Therefore, a study of isolated hyperthermic limb perfusion in four dogs was conducted using a balloon-occlusion technique including a hyperthermia unit, two low-flow rotary pumps, a bubble oxygenator, and two polyurethane balloon catheters. After 15 min infusion of cisplatinum the concentrations of serum platinum (Pt) in the isolated limb and in the whole body were measured by atomic absorption spectroscopy. Regional exposure to Pt was more than 10-fold higher than systemic exposure. After 60 min isolated limb perfusion, the area under the curve (AUC) of Pt concentrations in the isolated limb showed values between 767.4 and 1055.6 micrograms/l x 60 min, whereas in the whole body values between 59.8 and 75.9 micrograms/l x 60 min were obtained. Repeated isolated limb perfusions with the balloon-occlusion technique were performed in three dogs without systemic side effects. This model of regional chemotherapy may be useful for preoperative chemotherapy in malignant tumors of the limbs.

Animals↗
PubMed1994

Risk of falls after hospital discharge.

OBJECTIVES: To determine the incidence of falls within the first month after hospitalization and risk factors associated with falling during this period. DESIGN: Cohort study with 1-month follow-up after hospital discharge. SETTING: 370-bed community hospital. PATIENTS: Consecutive sample of 214 patients, aged 70 years and over, hospitalized for medical illness more than 48 hours and discharged to the community. EXCLUSION CRITERIA: terminal illness, neurologic diagnosis, discharge to skilled nursing facility. MEASUREMENTS: Information was obtained at hospital admission, discharge, and 1 month after discharge. Initial assessment included demographic data, vision, mood, pre-admission function, and use of assistive device. Discharge assessment included length of hospital stay, use of assistive device, need for professional help after discharge, medications cognition, and functional status. Patients were assessed 1 month after discharge for history of confusion and falls. Main outcome measure was falls in the first month after discharge. MAIN RESULTS: Twenty-nine patients (13.6%) fell during the month after discharge. Major risk factors for falls included, at discharge, decline in mobility (P = 0.005), use of assistive device (P = 0.002), and cognitive impairment (P = 0.05), and after hospital discharge, self-report of confusion (P = 0.002). Patients who were functionally dependent and needed professional help after discharge had the highest rate of falls (20.2%). In contrast, only 8.4% of independent patients not requiring professional help fell (P = 0.01). CONCLUSIONS: There is a high incidence of falls after hospital discharge, particularly among patients who are functionally dependent. Further study is needed to determine to what extent acute illness and hospitalization may influence falls risk.

Accidental Falls↗
PubMed1993

[The problems of quantifying pain in animals].

A classification of vertebrates concerning their pain sensibility from the anatomical or physiological point of view is made very difficult by the different pathways of nociception. The very good measurable stimuli are answered by a wide range of reactions. In search for approved parameters for the characterization of pain objectivity is often preferred to validity. Studies using animals in painful situations with and without analgetic treatment are considered favourable for pain evaluation. Each kind of evaluation of pain in animals has to take into account the different dimensions of pain perception. As a result we would like to follow Kitchell's statement (1980), as a guideline for the work with animals: "Overemphasis on the uncertainty of knowledge about pain in animals that leads to a denial that pain perception exists in animals is logically as well as empirically unfounded."

Animals↗
PubMed1993

[Sarcosporidia as the cause of sudden death during anesthesia in sheep].

The first two out of an experimental group of 17 sheep assigned for orthopaedic surgery died during inhalation anaesthesia with halothane-nitrous oxide-oxygen before the arthrotomy of the knee joint could start. Further casualties could be prevented by the use of epidural anaesthesia. Each of the 17 sheep underwent a pathologic-anatomical, histological, bacteriological and parasitological examination. It was found that all of them were infected with sarcosporidia-oocysts with myocarditis of different intensity. Possible infections with sarcosporidia-oocysts in animals, which could have had contact to carnivora, and which are taken for therapeutic surgery or for an experiment should be taken into consideration, because the lesion in the heart due to sarcosporidia-oocysts can be the cause of sudden death.

Anesthesia, Inhalation↗
PubMed1993

[Pain prevention and pain treatment in small and large domestic animals].

The aim of this article is to emphasize the need for analgesic medication in animals in possibly painful situations, especially in the postoperative period. The two large groups of compounds used as analgesics--the opiates and the nonsteroidal antiinflammatory drugs (NSAIDs)--are described with special reference to their pharmacokinetics, side-effects and toxicity, their mechanism of action, their indications and contraindications. Recommended doses of the different drugs available are given for the dog, the cat, the horse, the swine and the small and large ruminants.

Analgesia↗
PubMed1991

[Prevention of recurrence of Sudeck's disease with calcitonin].

In patients suffering from, or with a history of, reflex sympathetic dystrophy (RSD), there is always a risk of exacerbation or reactivation of this disease after surgery or trauma. The use of calcitonin in the treatment of this type of disorder is well established. Starting in 1984, 18 patients with clinical symptoms of RSD or a history of this disease were given daily prophylactic treatment with salmon calcitonin (100 IU subcutaneously or as a spray). Ten of the patients underwent orthopaedic surgery and 8 received conservative treatment following trauma. The mean duration of prophylactic treatment was 4 days before and 23 days after surgery or trauma. Only one recurrence was observed (3 per cent). For comparison, a retrospective analysis of a group with the same inclusion criteria who underwent surgery or received conservative treatment after trauma, without prophylactic administration of calcitonin showed a recurrence of the underlying disease 28 per cent of the cases. It is therefore possible to recommend prophylactic administration of calcitonin, to patients with a history of RSD who are about to undergo orthopaedic surgery or conservative treatment following trauma.

Adult↗
PubMed1990

[Sudeck's disease--its clinical picture and therapy].

Early diagnosis and medical as well as physical therapy are necessary to successfully treat reflex sympathetic dystrophy. Psychological support and guidance of the patient are also a must. Due to wide individual differences it is not possible to recommend any single therapy as the sole treatment. The choice of treatment must be selected not only according to disease stages but also taking the individual factors of each patient inter account. Therefore, therapy must often be modified during the course of treatment. As a result a favorable out-course can be expected in most cases. Today severe physical disabilities secondary to sympathetic reflex dystrophy is quite rarely encountered.

Combined Modality Therapy↗