Biomedical subjects
Publications and source records attributed to B Zimmer.
The structures of the title compounds have been determined by X-ray crystallography, using direct methods, and have been refined to conventional final residual factors of R = 0.063 and R = 0.046, respectively.
Case studies presented in the literature present evidence that individual factors may influence mandibular mobility unfavorably after mandibular advancement osteotomies. These factors are, respectively: high preoperative dysfunction index, preoperative articular pain in movement, preoperative reciprocal clicking, advanced patient age, and significant overjet reduction. This study identifies these individual factors, which can influence postoperative functional condition, and documents conclusively the importance of individual, function oriented preoperative planning in orthognathic surgery. Taken together these factors indicate that the adaptation ability of the effected tissue should be given greater attention in planning the operation.
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A longitudinal clinical-axiographic study including 10 patients who had undergone surgical mandibular advancement to correct a dental and skeletal Class II anomaly, produced evidence of correlations between alterations of acoustic symptoms and of mandibular mobility. In 7 of 11 movements, where TMJ-sounds disappeared, post-operative mandibular mobility was reduced to such a degree that the point at which the acoustic symptom originated pre-operatively could no longer be attained. On the other hand, in all cases, where TMJ sounds remained uninfluenced by the surgical intervention, reductions in mobility occurred only beyond this point. Even the persistence of losses of TMJ sounds during the further post-operative follow-up period could, in the majority of cases (4 of 7) be well explained by the persistence of mobility restriction. Accordingly, in the future a differentiation between mobility- and non-mobility-dependent alterations of TMJ symptoms should be made.
Child abuse by whiplash-shaking can lead to severe cerebral damage, neurological defects and mental retardation. Cerebral damage has been found with and without external evidence of head injury. We report the sonographic findings in two children after traumatization due to repetitive vigorous whiplash shaking. Cerebral sonography revealed cerebral edema at admission or within 48 hours thereafter. Follow-up studies demonstrated development of marked brain atrophy in both cases. The sonographic findings were confirmed by cranial computerized tomography. Doppler sonography was used to monitor cerebral perfusion by measuring intracranial blood flow. The clinical history of the patients demonstrates that cerebral sonography in combination with Doppler sonography not only serves as a diagnostic tool but also allows adjustment of therapy to the actual clinical status of the patient.
A prospective study including 63 adult Class II and Class III patients was carried out in order to examine short- and long-term effects of four different treatment methods on mandibular mobility. The patients were treated either (Group A, control-group) orthodontically alone or (Group B) by a LeFort I-osteotomy, a (Group C) mandibular advancement or (Group D) a two-jaw surgery/mandibular set-back. In the surgery-groups (B, C, and D) maximum opening, protrusion and lateral excursions were measured 2 days pre-operatively (T0), and 3, 8, 14.5, and 25.5 months post-operatively (T1-T4). In the control-group (A) at T0 and T4 was measured, only. Significantly differing effects of the four treatment methods on mandibular mobility were detected. (A) Orthodontic treatment alone, (B) maxillary advancement by LeFort I osteotomy, and (D) two-jaw surgery/mandibular set-back osteotomy did not influence mandibular mobility permanently. Temporary decreases in groups B and D (P less than or equal to 0.05) were observed, however. In contrast, permanent reductions after (C) mandibular advancement took place (P less than or equal to 0.001). Longitudinal survey showed that in all surgery groups recoveries were limited to a short period of 3-14.5 months, depending on the movement. Surprisingly, a closer similarity between the LeFort-I group (B) and the two-jaw surgery group (D), rather than between the sagittal-split groups (C and D), was seen indicating that the problem of reduced mobility after orthognathic surgery can be limited to Class II therapy. It was concluded that in Class III therapy, the application of rigid fixation in combination with a method of maintaining condyle-position, thereby dispensing with maxillomandibular fixation, prevents permanent reductions in mobility and guarantees a rapid recovery to pre-operative mobility levels.
OBJECTIVE: To evaluate the hemodynamic effects of tolazoline and prostacyclin in infants with pulmonary vasospasm after cardiac surgery. DESIGN: Prospective cohort study. SETTING: Pediatric ICU. PATIENTS: The cohort consisted of 42 infants and children with congenital heart disease and pulmonary hypertension who underwent corrective surgery and were monitored postoperatively using pulmonary artery catheters. Fourteen infants (2 to 12 months old) in this group required postoperative treatment with tolazoline or prostacyclin. INTERVENTIONS: Tolazoline was administered as a bolus of 0.5 mg/kg for treatment of persistent pulmonary hypertension or acute pulmonary hypertensive crisis. If its effectiveness was proved after 30 mins by hemodynamic measurements, a continuous iv infusion of 0.5 mg/kg/hr was established. Higher doses of tolazoline were avoided. If tolazoline treatment did not fulfill the criteria for pulmonary vasodilation, prostacyclin was given by continuous iv infusion at a starting rate of 5 ng/kg/min, followed by 10 ng/kg/min. In three patients, the infusion rate was increased to 15 ng/kg/min. RESULTS: Bolus administration of tolazoline resulted in a distinct pulmonary vasodilation in seven infants: mean pulmonary artery pressure and pulmonary vascular resistance decreased by an average of 35% and 45%, respectively. In these patients, tolazoline was infused over the following 12 to 72 hrs. One infant who received tolazoline for 72 hrs developed a clinically important gastrointestinal hemorrhage. In seven nonresponders to tolazoline, prostacyclin (PGI2) at an infusion rate of 5 ng/kg/min led to pulmonary vasodilation in five patients, at an iv infusion rate of 10 ng/kg/min in all seven infants studied. The latter dose of PGI2 reduced the mean pulmonary artery pressure by an average of 37%, and pulmonary vascular resistance by 43%. Transient withdrawal of prostacyclin in five infants demonstrated its short half-life and clinical effectiveness. Apart from a facial flush, no side-effects were encountered using PGI2 as an infusion over durations ranging from 12 to 504 hrs. CONCLUSIONS: These data suggest that, if tolazoline in a relatively low dose proves to be inefficient, prostacyclin can still be used as a safe and effective drug for treatment of pulmonary vasospasm. Prostacyclin offers more than a pharmacologic alternative to increased tolazoline dosages.
We investigated the effects of different polyunsaturated fatty acids (PUFAs) of the n-6 and n-3 family on the PAF and LTD4 stimulated increase in cytosolic free Ca(2+)-concentration [Ca2+]i in retinoic acid (RA) differentiated, human monocytic U937 cells. Docosahexaenoic acid (10 microM DHA) reduced the PAF induced increase in [Ca2+]i from 455 +/- 25 nM to 319 +/- 24 nM (P less than 0.01). DHA also significantly attenuated the LTD4 induced increase in [Ca2+]. However [Ca2+]i-increase stimulated by f-MLP, ATP, or ionophore A 23187 was not affected by DHA. Other PUFAs like eicosapentaenoic acid (EPA), alpha-linolenic acid (LnA), arachidonic acid (AA) or gamma-linoleic acid (LA) were ineffective. Cellular differentiation as assessed by nitrobluetetrazolium reduction and enhanced expression of specific PAF binding sites in RA treated cells were not altered by DHA. Fatty acid composition in cellular phospholipids revealed effective incorporation of each PUFA. The DHA-effect on [Ca2+]i was time dependent and occurred at 48 h, whereas the DHA-content in phospholipids reached a plateau already at 24 h. The antioxidant vitamin E, the lipoxygenase inhibitor NDGA and the cytochrome P-450 inhibitor SKF 525A completely prevented the DHA induced reduction of PAF stimulated [Ca2+]i-increase. In contrast, the cyclooxygenase inhibitor indomethacin had no effect. Our results indicate that DHA selectively reduces intracellular [Ca2+]i-increases induced by PAF and LTD4 in RA-treated U937 cells, presumably involving an oxidative modification of DHA.
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A prospective follow-up study of 21 class-II patients, who were treated with a combination of orthodontics and orthognathic surgery, revealed typical postoperative changes in opening mobility. Their characteristics were: a strong initial loss of mobility and a regeneration period of about one year. Because the increase of mobility could not completely compensate for the initial reduction, a significantly reduced mobility was detected 25.5 months postoperatively. This reduction was considered as clinically acceptable, since former studies showed more unfavorable developments. However, individual changes of mobility are worth of notice. The comparison of condylar-related axiographic measurements with incisal measurements showed that the reduction of the length of axiographic tracings was more prominent than the "clinical-effective" reduction of the combined condylar rotation and translation.
A longitudinal study of TMJ sounds prior to and after combined orthodontic-orthognathic surgical procedures was carried out. The relative frequency of such sounds two days prior to operation (T0) and three months (T1), eight months (T2), 14.5 months (T3), and 25.5 months (T4) postoperatively remained--treatment-independently--largely unchanged. Chances in frequency between T0 and T4 showed only a nonsignificant tendency to differ in comparison with changes seen after orthodontic treatment (A) only. An analysis of individual changes revealed that after Le Fort I osteotomy (B) and bimaxillary procedures/posterior mandibular repositioning (D), no change in the preoperative sounds is to be expected. In contrast, following mandibular advancement (C) TMJ sounds first disappeared, in particular in the period immediately following operation (T0-T1), but also subsequently reappeared. The difference vis-a-vis group B (Le Fort I osteotomies) was statistically significant (group B vs. group C: p less than or equal to 0.01.
Fifty-seven non-orthodontically treated young adults, judged as either clinically healthy or with only mild symptoms of TMJ-dysfunction, were divided into groups according to their sagittal molar relationship (Class I-, Class II-, and Class III-group). All underwent a standardized clinical and axiographic examination with an axiographic recording device (SAS-SYSTEM). The comparison of the lengths of the axiographical protrusive curves showed significantly higher values in the Class II group than in the Class I (P less than 0.01) and in the Class I group than in the Class III group (P less than 0.001). Analogous differences could be found in clinical protrusive measurements at the incisal point and in lateral excursions. It was concluded that the protrusive condylar movement capacity coincides with the dental sagittal relationship. In opening, significant differences were seen axiographically (Class I v. Class III: P less than 0.001; Class II v. Class III: P less than 0.01), but not clinically. Since axiographic measurements show only condyle translation, but not rotation in contrast to measurements at the incisal point, it can be concluded that the differences in opening are also translatory and not rotational. Measurements of the average change of curvature of axiographic tracings showed significantly less curved protrusive tracings in Class III than in Class I (P less than 0.001) and Class II individuals (P less than 0.01), supporting the concept that in the Class III group condyle movement is restricted to the straight posterior slope of the tubercle.(ABSTRACT TRUNCATED AT 250 WORDS)
In orthognathic surgery a three-dimensional positioning of the maxilla is possible by means of the Le Fort I osteotomy and subsequent maxillary movement. In treatment planning and at the time of surgery it is very important to achieve an exact positioning of the upper incisors in relation to the upper lip and the rest of the skull. The Model Positioning Device described here allows three-dimensional positioning of the upper incisors in one- or two-jaw surgery. The reference plane is the upper surface of the upper part of a semi-individually adjustable articulator. The application of the Sandwich Splint enables the three-dimensional positioning of the maxilla in relation to the rest of the skull. The Sandwich Splint ensures that the vertical position of the mandible in relation to the rest of the skull above the osteotomy plane is exactly reproducible in the pre- and post-operative situation in both model surgery and at time of surgery. To this mandibular position the maxilla is positioned in three dimensions, as preplanned. The vertical dimension, which is identically reproducible before and after surgery is measured with a caliper. After surgery the mandible can be rotated into the planned new intercuspidation.
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Recent reports supporting the use of lithium carbonate as an adjunct to tricyclic antidepressants for the treatment of refractory depression have not utilized standardized tricyclic antidepressant therapy, nor have they addressed the efficacy of lithium augmentation in a geriatric population. A 3-week open trial was added to the medication regimen of 15 elderly depressed inpatients who had already failed 4 weeks of therapeutic levels of nortriptyline. Treatment response was determined by the 17-item Hamilton Rating Scale for Depression (HAM-D). Two of 15 partial responders before lithium augmentation became complete responders. Of the remaining 13 "nonresponders" before lithium augmentation, one had a complete response, 7 had a partial response and 5 remained nonresponders. Although there was a mean HAM-D change of 8.3 points after lithium augmentation (24.7 +/- 5.9 to 16.4 +/- 6.8, p less than .001), when considering the previously reported similar efficiency of extended nonaugmented nortriptyline, these data do not strongly support lithium augmentation in elderly subjects who fail to respond after 4 weeks of nortriptyline. Further study is needed to determine what role, if any, lithium augmentation should play in the treatment of geriatric depression.
Ischemia and hypoxia are frequent potential sources of secondary brain damage after a variety of brain injuries. Cerebral oxygen extraction may be altered by coma as well as therapeutic interventions. In consequence, monitoring of cerebral O2 availability and utilization has become an important challenge for clinicians. However, measurement of cerebral oxygen extraction in children currently is not included into routine clinical care. This paper describes the measurement of O2-saturation in the jugular bulb in four comatose infants and children (in one continuously) following cardiac arrest or head injury. Our data demonstrate that this procedure served as a valuable tool in the management of those patients. Arterio-jugular oxygen content and lactate differences were used for the establishment and adjustment of therapeutic procedures and moreover, provided relevant information for the interpretation of other cerebral surveillance parameters.
The Cancer and Leukemia Group B (CALGB) utilized a randomized phase II trial design to evaluate two cisplatin-based combinations, cisplatin-cytarabine (ara-C) and cisplatin-vinblastine, in 151 patients with advanced non-small cell lung cancer. Patients entered on study had not received prior chemotherapy. Platinum doses were equivalent in the two treatment programs. The total response rate (complete response, partial response, regression of evaluable disease) for the cisplatin-vinblastine group was 22% (16/73). Failure-free survival at six months for this group was 41%, survival at six months was 63%. The cisplatin-ara-C group had a total response rate of 9% (7/78) with a failure-free survival at six months of 14% and a six-month survival of 47%. Severe or life-threatening toxicity was seen in 73% of cisplatin-vinblastine cases and 59% of cisplatin-ara-C patients. Neither regimen is active enough to warrant designation as "standard therapy" for patients with M1 disease.