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Biomedical subjects

B Zimmer

Publications and source records attributed to B Zimmer.

At least 19 recordsLinked to original sources
PubMed1997

Evaluation of pharmacokinetics, safety, tolerance, and activity of combination of zalcitabine and zidovudine in stable, zidovudine-treated pediatric patients with human immunodeficiency virus infection. AIDS Clinical Trials Group Protocol 190 Team.

A double-blind phase II trial compared zalcitabine (0.03 mg/kg/day) in combination with zidovudine (720 mg/m2/day) and zidovudine monotherapy in 250 clinically stable, previously zidovudine-treated, human immunodeficiency virus-infected children. The combination was well-tolerated except for an increased incidence of neutropenia (14%) compared with that in children receiving monotherapy (5%). No differences were noted for time to first AIDS-defining illness or death, neuropsychologic status, or weight Z scores. In patients in the combination arm, the CD4 cell count decline was slower (13% per year) than in patients receiving monotherapy (25% per year) (P = .03), and quantitative peripheral blood mononuclear cell virus load remained lower at all time points (P = .08). Deaths were fewer in patients receiving combination therapy (4) compared with those in patients receiving monotherapy (10) (P = .083). Thus, administration of zidovudine with zalcitabine to children with prior zidovudine treatment did not result in a significant increase in toxicity compared with that resulting from zidovudine monotherapy and demonstrated improvement in immunologic and virologic surrogate markers.

AIDS-Related Opportunistic Infections↗
PubMed1994

Tuberculosis in human immunodeficiency virus-exposed or -infected United States children.

This study was designed to provide a preliminary assessment of the occurrence of tuberculosis exposure, infection and disease within a national sample of infants and children with human immunodeficiency virus (HIV) exposure or infection, and to determine the prevalence of Mycobacterium tuberculosis isolates resistant both to isoniazid and rifampin in these patients or their adult source contacts. A retrospective questionnaire survey was conducted of infants and children with HIV exposure or infection evaluated by pediatric HIV referral centers in the United States comprising the pediatric units or subunits of the Pediatric Acquired Immunodeficiency Syndrome Clinical Trials Group (PACTG). Seventy of 72 sites during a mean period of 5 (range, 1 to 12) years participated in this study and had provided care for 14,038 patients. There were 75 cumulative total cases of tuberculosis disease seen since each site was established. Therapy for asymptomatic infection was given to another 40 children and for tuberculosis exposure to 71 children. Annualized case rates were 478/100,000 for sites established in 1990 to 1992, 117/100,000 for 1988 to 1989, 63/100,000 for 1986 to 1987 and 58/100,000 for 1981 to 1985 (P = 0.05, Spearman's p test for trend). By comparison, the 1992 age-specific tuberculosis case rate for all U.S. children < 5 years was 5.5/100,000. Twenty percent of isolates from PACTG patients and 15% of isolates from adult source contacts were resistant to isoniazid and rifampin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Lovastatin increases arachidonic acid levels and stimulates thromboxane synthesis in human liver and monocytic cell lines.

The effect of lovastatin (LOV), the inhibitor of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase, on linoleic acid (LA, 18:2n-6) metabolism was examined in human monocytic Mono Mac 6 (MM6) and hepatoma Hep G2 cells. The desaturation of LA was examined after LOV (72 h, 10 microM) or dimethylsulfoxide (LOV carrier, < 0.1%) and [14C]LA (last 18 h, 0.3 microCi, 5 microM). In both cell lines, LOV reduced the percentage of 14C label associated with LA and increased the percentage of label in the 20:4n-6 and the 22:5n-6 fractions. In Hep G2 but not MM6 cells, this effect was fully reversible by means of coincubation with mevalonic acid (500 microM), but not with cholesterol or lipoproteins. In both cell lines, the LOV-mediated increase in LA desaturation resulted in dose-dependent reductions of LA and elevations of AA in cellular phospholipids. The lipids secreted by LOV-treated Hep G2 cells were also enriched in arachidonic acid (AA). In the MM6 cells, LOV increased release of thromboxane upon stimulation with the calcium ionophore A23187. In summary, our findings of higher LA desaturation and AA enrichment of lipids secreted by the Hep G2 cells suggest that LOV treatment may increase the delivery of AA from the liver to extrahepatic tissues. The changes in membrane fatty acid composition can influence a variety of cellular functions, such as eicosanoid synthesis in monocytic cells. The mechanism appears to be related to the reduced availability of intermediates of cholesterogenesis.

Analysis of Variance↗
PubMed1994

[Mucinous cystadenomas and cystadenocarcinomas of the pancreas--the pancreaticoscopy as a new device for endoscopic and histological diagnosis].

Recent advances in diagnostic imaging procedures offer the opportunity for detection of rare cystic neoplasms of the pancreas. Cystadenomas of the pancreas have been reported to represent 10% of cystic pancreatic lesions. Serous microcystic cystadenoma, megacystic mucinous and duct-ectatic mucinous cystadenoma were distinguished. While the serous cystadenoma is benign, in general the megacystic and the duct-ectatic mucinous cystadenoma have a significant malignant potential. With pancreatoscopy, a rather new endoscopic technique, five cases of mucinous megacystic cystadenoma were diagnosed preoperatively by macroscopic and microscopic means. In one case, development of malignant neoplasm was diagnosed, one patient did not undergo surgery because of her age. Three patients were operated (total pancreatectomy in one case, duodeno-hemipancreatectomy in two cases) and are without any further signs of recurrence and free of symptoms in a one year to four year clinical follow-up.

Adult↗
PubMed1993

[Temporomandibular joint function after orthognathic surgery--the individual factors].

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.

Adaptation, Physiological↗
PubMed1993

Correlations between the loss of acoustic TMJ symptoms and alterations in mandibular mobility after surgical mandibular advancement.

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.

Adolescent↗
PubMed1992

Battered child syndrome: cerebral ultrasound and CT findings after vigorous shaking.

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.

Battered Child Syndrome↗
PubMed1992

Changes in mandibular mobility after different procedures of orthognathic surgery.

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.

Adolescent↗
PubMed1992

Effects of tolazoline and prostacyclin on pulmonary hypertension in infants after cardiac surgery.

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.

Drug Evaluation↗
PubMed1991

Docosahexaenoic acid inhibits PAF and LTD4 stimulated [Ca2+]i-increase in differentiated monocytic U937 cells.

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.

Animals↗
PubMed1991

[Changes in opening mobility due to surgical advancement of the mandible].

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.

Adult↗
PubMed1991

[Longitudinal changes in the acoustic temporomandibular symptoms due to different procedures of orthognathic surgery].

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.

Auscultation↗
PubMed1991

Comparison of 'normal' TMJ-function in Class I, II, and III individuals.

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)

Adult↗