Search PubMed⌕ Search

Biomedical subjects

J Schwarz

Publications and source records attributed to J Schwarz.

At least 91 records · Page 5Linked to original sources
PubMed1999

Relative quantification of signal on T2-weighted images in the basal ganglia: limited value in differential diagnosis of patients with parkinsonism.

A reduction in signal in the basal ganglia on T2-weighted images is said to correlate with a poor response to L-DOPA and may help to identify patients with non-idiopathic parkinsonism. Our aim in this prospective study was to use the contrast-to-noise ratio of the MRI signal on T2-weighted images in various parts of the basal ganglia in 43 patients with de novo parkinsonism. Signal intensity measurements were compared to the response to the dopamine agonist apomorphine and dopamine-D2 receptor binding obtained by 3-iodo-6-methoxybenzamine single-photon emission computed tomography (IBZM-SPECT). A reduced contrast-to-noise ratio in the putamen correlated significantly with a negative response to apomorphine and reduced striatal IBZM binding. No additional signal intensity measurement correlated with response to apomorphine or specific IBZM binding. However, there was a considerable overlap of contrast-to-noise ratios between patients with a positive or negative response to apomorphine or normal and reduced IBZM binding. We suggest that semiquantitative assessment of signal intensity in the putamen shows a significant reduction in patients with probably nonidiopathic parkinsonism compared with patients with probably idiopathic parkinsonism. However, this method does not exclude idiopathic parkinsonism in a given patient.

Adult↗
PubMed1999

HEK-293 cells expressing the human dopamine transporter are susceptible to low concentrations of 1-methyl-4-phenylpyridine (MPP+) via impairment of energy metabolism.

Selective dopaminergic neurotoxicity induced by 1-methyl-4-phenylpyridine (MPP+) is believed to be due to the transmembrane uptake by the dopamine transporter and subsequent inhibition of mitochondrial complex I and/or production of free radicals. However, little is known about the molecular sequence of intracellular events leading to cell death induced by low concentrations of MPP+. Here we stably express the human dopamine transporter (hDAT) in human embryonic kidney HEK-293 cells to correlate cytotoxicity and indices of cellular energy metabolism after exposure to low concentrations of MPP+. The permanent ektopic expression of hDAT in HEK-293 cells confers time and dose-dependent cytotoxicity at nanomolar concentrations of MPP+ with an IC50 value of 740 nM after 48 h. MPP+ initially induces a fast increase of cellular NADH content within the first 6 h, followed by a slow reduction of intracellular ATP (IC50 value of 690 nM after 48 h) as well as reduction of intracellular ATP/ADP ratio. These changes of cellular energy metabolism precede reduction of cell viability. The toxic effects of MPP+ are blocked by the hDAT inhibitor GBR12909 with EC50 values of 110 and 60 nM for cytotoxicity and ATP depletion, respectively. Antioxidants such as D-alpha-tocopherol and ascorbic acid do not have significant protective effects against MPP+ toxicity. This study shows that HEK-293 cells expressing the hDAT gene are highly sensitive to MPP+ due to (i) transmembrane uptake of MPP+ by the dopamine transporter, (ii) cellular energy depletion, probably caused by inhibition of mitochondrial complex I activity and (iii) that the toxicity is independent from the presence of antioxidants. This cell system may serve as a screening system for endogenous and exogenous compounds with similar effects compared to MPP+ as well as protective agents.

1-Methyl-4-phenylpyridinium↗
PubMed1999

Laparoscopic surgery complications associated with trocar tip design: review of literature and own results.

In the last 10 years, there has not been an abdominal surgical procedure that has not been performed by laparoscopic means. The enthusiasm of surgeons active in this field often neglects problems, especially with basic instruments which are important vehicles for the laparoscopic technique. The purpose of this study was to focus on trocar-related problems with special respect to the tip design. On the basis of a prospective study of laparoscopic transperitoneal hernia repair (TAPP) and laparoscopic Nissen fundoplication, we evaluated our data concerning trocar-related complications at the abdominal wall. We compared two groups of patients treated in a nonrandomized design with either sharp cutting single-use trocars or cone-shaped non-cutting reuseable trocars. The evaluation of our own data showed an incisional hernia in 1.83% of patients treated with a sharp trocar tip, a complication which could be significantly lowered, to 0.17%, with a conic tip design. Similar results could be seen with trocar-related bleeding events at the insertion site in the abdominal wall. In most publications, trocar design and related complications are unmentioned. Our data demonstrate a reasonable benefit for a conic tip design, which enables atraumatic insertion through the abdominal wall. The reuseable steel version furthermore holds a considerable cost-saving potential.

Equipment Design↗
PubMed1999

Falls among healthy, community-dwelling, older women: a prospective study of frequency, circumstances, consequences and prediction accuracy.

OBJECTIVE: Most studies of falls among older people have focused on those with some degree of balance or mobility impairment. This study aimed to establish whether falls and associated injuries were a major problem among healthy, older women, whether there were some common features in the falls, and whether these falls could be accurately predicted. METHOD: Ninety-six healthy, active community-dwelling women in Melbourne, Australia, aged at least 70 years (mean 74.1 +/- 4.0) were initially measured on a comprehensive series of laboratory and clinical balance tests, gait, strength and psychometric measures. Subjects were monitored for falls events, circumstances and consequences by use of falls diaries and monthly phone calls. Baseline measures of clinical balance measures and gait were comparable to other studies reporting scores on these measures in samples of healthy older people. RESULTS: During the 12-month follow-up period, 49% of subjects fell, with 23% falling more than once; 9% suffered fractures as a result of their fall and 10% suffered strains or other moderate injuries. Many of the falls occurred during non-threatening activities such as walking, often under altered sensory or environmental conditions. Multivariate logistic regression identified gait symmetry and gait double support duration as the variables most strongly associated with prediction of multiple fallers. CONCLUSIONS: The results highlight that falls are a major problem among healthy active older women, and that targeted falls prevention programs are required for this group.

Accidental Falls↗
PubMed1998

Microglial activation in multiple system atrophy: a potential role for NF-kappaB/rel proteins.

Microglial activation is a prominent feature of affected brain areas in multiple system atrophy. Microglia express proinflammatory peptides, which may be a result of activation of nuclear factor-KB. We investigated the nuclear presence of RelA, the 65 kDa subunit of the NF-KB/RelA family in striatum and brain stem of patients with multiple system atrophy. Affected brain areas of patients with multiple system atrophy showed a marked immunoreactivity for nuclear Rel A p65, which was almost exclusively localized in activated microglia. Interestingly nuclear translocation of Rel A was not detected in striatal tissue of controls and Parkinson disease patients. Thus, NF-kappaB/Rel A complexes may play a role in mediating microglial activation in multiple system atrophy.

Aged↗
PubMed1998

[Bleeding gastroduodenal ulcers from the viewpoint of the surgeon].

The article has discoursed of a diagnosis and a therapy of bleeding peptic ulcer. There has been used the group of the patients admitted at The Surgical Unit of The Faculty Hospital Motol in Prague during two and half years. Urgent endoscopy and endoscopic treatment of indicated findings have been performed as a common procedures. The surgical therapy has been necessary for the part of this patients. Operation's indications, types of the operations and their timing have been discussed.

Humans↗
PubMed1998

Reduced striatal dopaminergic innervation shown by IPT and SPECT in patients under neuroleptic treatment: need for levodopa therapy?

We investigated the availability of dopamine reuptake sites in the striata of two patients with productive symptoms and neuroleptic therapy as well as progressive parkinsonism using the new dopamine transporter ligand [123I]N-(3-iodopropen-2-yl)-2beta-carbo-methoxy-3beta- (4-chlorophenyl)tropane (IPT) and single photon emission computed tomography (SPECT). Normal specific binding in the caudate nucleus was 8.6 +/- 1.2 and in the putamen 6.5 +/- 1.3 (mean +/- S.D.; n = 8; mean age, 56.7 years; range 41-67 years). Patient 1 (age 43) was admitted to our clinic at age 38 because of left-sided parkinsonism. At age 40, she developed paranoid psychosis without change after cessation of L-DOPA and lisuride treatment for 3 months. She was diagnosed as a schizophrenic, paranoid subtype (DSM-III-R). IPT-SPECT showed a loss of dopaminergic nerve terminals (right caudate/putamen, 5.16/2.0; left caudate/putamen, 5.92/2.66). Patient 2 (age, 61 years) had a history of paranoid psychosis for approx. 30 years. He experienced progressive right-sided parkinsonism since age 57 when treated with clozapine. IPT-SPECT showed a marked reduction of striatal dopamine transporter binding (right caudate/putamen, 5.06/1.65; left caudate/putamen, 3.8/1.12). Our findings indicate that patients may suffer contemporaneously from Parkinson's disease and schizophrenia. In these patients, the proof of a nigrostriatal dopaminergic deficit justifies treatment with neuroleptics and dopaminergic drugs. Imaging of dopamine transporters with SPECT and IPT or a related compound represents an attractive alternative to the more complex measurements of fluorodopa uptake with positron emission tomography (PET).

Adult↗
PubMed1998

123I-IBZM binding compared with long-term clinical follow up in patients with de novo parkinsonism.

We performed a prospective clinical follow up (mean follow up, 36 months; range, 24-56 months) of 65 patients with de novo parkinsonism in whom imaging of dopamine D2 receptors was performed before the initiation of dopaminomimetic therapy by means of 123I-iodobenzamide-single-photon-emission computed tomography (IBZM-SPECT). The results of IBZM-SPECT were compared with the long-term response to dopaminomimetic drugs, the development of motor fluctuations, and the development of clinical signs incompatible with Parkinson's disease (PD). A total of 55 patients had normal and 10 patients had reduced IBZM binding; 45 patients showed a good response to levodopa (L-dopa), 11 showed an equivocal response, and nine did not respond; 31 patients developed a fluctuating response to dopaminomimetic drugs and seven patients developed clinical signs indicative of multiple-system atrophy (n = 5), progressive supranuclear palsy (n = 1), or corticobasal ganglionic degeneration (n = 1). Chi-squared analysis showed a significant correlation of the results of IBZM-SPECT with the long-term response to dopaminomimetic therapy (p < 0.0001) and the development of motor fluctuations (p < 0.001) or clinical signs incompatible with PD (p < 0.0001). We conclude that IBZM-SPECT can help to differentiate between patients who will show a good response to L-dopa and will develop motor fluctuations (most likely patients with PD) and those patients who will not respond to L-dopa and might develop clinical signs compatible with another hypokinetic disorder of the basal ganglia.

Adult↗
PubMed1998

Chronic TVP-1012 (rasagiline) dose--activity response of monoamine oxidases A and B in the brain of the common marmoset.

The stereospecific form of the known acetylenic mechanism-based MAO-inhibitor AGN1135 (Rasagiline, TVP-1012) is devoid of sympathomimetic amphetamine-like properties. To evaluate the efficiency and selectivity of subcutaneous injections of TVP-1012 (dose range from 0.01 up to 10 mg/kg for 7 days) the activities of monoamine oxidases A and B (MAO-A,-B) were determined in different brain regions of the common marmoset. At a dose of 0.1 mg/kg TVP-1012, almost 80% of MAO-B activity is inhibited in all brain regions investigated (prefrontal and occipital cortex, cerebellum, caudate nucleus, putamen, nucleus accumbens). In contrast, MAO-A is not inhibited in putamen and nucleus accumbens. However, by increasing the TVP-1012 dose to 0.5 mg/kg, MAO-A is inhibited to a significant extent as well, concomitant to total inhibition of MAO-B. The results obtained indicate that TVP-1012 irreversibly inhibits both types of MAO in the common marmoset with selectivity for MAO-B at doses less than 0.5 mg/kg. TVP-1012 could be useful in studies requiring selective MAO-B inhibition without concomitant sympathomimetic amphetamine-like effects and could thus be of therapeutic interest for Parkinson's disease and retarded depression.

Animals↗
PubMed1998

[Risks and benefits of laparoscopic hernia-plasty (TAPP). 5 years experiences with 3,400 hernia repairs].

In the present study, for the first time the aspects of risk, benefit and the costs of laparoscopic hernioplasty in the transabdominal technique with preperitoneal placement of a polypropylene mesh are examined prospectively in a very large group of patients with 3,400 hernia repairs. The median operation time was 45 min for unilateral primary hernias, 50 min for unilateral recurrent hernias and 76 min for bilateral hernias. The frequency of complications showed a significant dependence on the individual steps in the development of the method and the individual learning curve. The same is true for the rate of recurrency. Whereas initially the rate of serious complications was 2.75%, the rate of minor complications 11% and the rate of recurrences 4.5% the corresponding figures are at present 0.4%, 4.4% and 0.5%. Laparoscopic hernioplasty proved to be equally as effective in the treatment of primary hernias, recurrent hernias and bilateral hernias. The large number of 11 surgeons participating proves that laparoscopic hernioplasty can be learned and that even in a teaching hospital it can be performed safely, efficiently and cost-effectively.

Adolescent↗
PubMed1998

Effects of macrophage migration inhibitory factor and macrophage migration stimulatory factor on function and survival of foetal dopaminergic grafts in the 6-hydroxydopamine rat model of Parkinson's disease.

Activated microglia play an important role in the rejection of intracerebral grafts and the degeneration of axotomized neurones. We studied the effect of macrophage migration stimulatory factor (MSF) or macrophage migration inhibitory factor (MIF) on allogeneic foetal mesencephalic dopaminergic grafts transplanted into the striatum of 6-hydroxydopamine-lesioned rats. Rotation testing revealed a significant compensation of lesion-induced motor asymmetry 3 weeks post-grafting in animals treated with MIF and vehicle-treated controls compared with pre-graft values (Student's t-test, P < or = 0.005) and MSF-treated animals (ANOVA, post hoc Fisher PLSD test, P < or = 0.05). The MSF group showed no significant compensation. Graft recipients with MIF application (1452.06 +/- 164.32 tyrosine hydroxylase-positive ventral mesencephalic cells) and controls (1753.21 +/- 165.51 tyrosine hydroxylase-positive neurones) displayed good graft survival. Animals with MSF application showed a significant reduction of tyrosine hydroxylase-positive grafted cells (MSF 570.36 +/- 209.49 cells) and graft volumes compared with the MIF and the control group (ANOVA, post hoc Fisher PLSD test, P < or = 0.05). The proportional area of microglia was significantly reduced in MIF animals compared with control animals (ANOVA, post hoc Fisher PLSD test, P < or = 0.001). Activated microglia and macrophages were reduced by half in the MIF-treated group compared with MSF animals and controls. We conclude that intrastriatal injections of MSF result in impaired function and survival of allogeneic ventral mesencephalon (VM) grafts 3 weeks after transplantation. MIF can reduce the number of microglia and macrophages in allogeneic foetal VM grafts. A reduction of microglia via MIF application did not enhance graft function and survival.

Animals↗
PubMed1998

A single institution's experience with transperitoneal laparoscopic hernia repair.

BACKGROUND: Previous evaluations of endoscopic hernia surgery mostly are based on small prospectively documented series or on a few randomized comparative studies. In the following, results of a large single-institution experience concerning the transabdominal preperitoneal patch (TAPP) technique with regard to the development of methods and the routine use are described. METHODS: From April 1993 to March 1997, 2,700 TAPP procedures were performed at the Department of General and Visceral Surgery, Marien-hospital, Stuttgart, Germany. The follow-up was documented prospectively in all cases by use of computed data base. RESULTS: The majority of patients (83.8%) were operated because of primary hernias. In 17.2% a first or multiple recurrence of an inguinal hernia was indicated. At a median postoperative observation period of presently 20 months and a follow-up rate of 86.5%, 28 recurrences have been determined so far (total recurrence rate 1.03%), 6 of which occurred after a recurrent hernia reparation (1.33%) and 22 after primary hernia repair (0.97%). The most common cause for recurrence was in 39.3% a mesh (12 x 8 cm) being too small. The total complication rate was 4.6%; as an expression of the learning curve it was reduced from 7.8% (operations 1 to 500) to 2.8% (operations 2,200 to 2,700). CONCLUSIONS: According to our experience, the TAPP technique is sufficiently applicable as a standard method for an unselected group of patients in a routine setting. It is especially suited to the repair of recurrent and bilateral hernias as well as for patients with a high risk for recurrence that can profit from a tension-free endoscopic procedure, particularly in case of obesity.

Female↗
PubMed1998

Dopaminergic deficit in amyotrophic lateral sclerosis assessed with [I-123] IPT single photon emission computed tomography.

Dopamine transporter imaging was performed in 18 patients with sporadic amyotrophic lateral sclerosis (ALS) and 11 age matched controls with [I-123] IPT (N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta(4-chlorophen yl)-tropane), a new cocaine analogue that selectively binds to the dopamine transporter located on dopaminergic nerve terminals. Image analysis showed that striatal IPT binding was moderately but significantly reduced in the ALS group compared with controls (p<0.01). The reduction of IPT binding was similar for patients with bulbar onset compared with those with limb onset. There was no correlation between values for uptake of striatal IPT and the age of the patients or the duration of the disease. These data indicate that nigrostriatal dopaminergic neurons are subclinically affected in a subset of patients with sporadic ALS.

Adult↗
PubMed1998

Effect of motion contrast on human cortical responses to moving stimuli.

The cortical areas activated by motion-defined contours were studied in humans using positron emission tomography (PET). Subjects observed four types of random dot fields, displayed through a 21 degrees diam aperture: unidirectional motion of a translating dot field, motion in opposing directions of two superimposed translating fields, motion in opposing directions of dots in contiguous spatial regions (motion contrast), producing a square wave grating defined by motion, and luminance variation of stationary dots in contiguous spatial regions, producing a square wave grating defined by luminance. Relative to a static dot field, the unidirectional motion condition activated areas previously described, including areas 17/18, lateral temporal-occipital-parietal cortex (MT/MST), and the superior temporal sulcus. Motion-defined gratings increased the activation of areas 17/18 and MT/MST, but not the superior temporal sulcus, and added more dorsal areas in the cuneus, roughly corresponding to V3/V3a, and ventral areas in the lingual gyrus/collateral sulcus, roughly corresponding to V2/VP. Luminance defined gratings, relative to a static dot field, activated areas 17/18, regions in the dorsal cuneus similar to those activated by motion defined gratings, and a region near the left collateral sulcus, slightly lateral to the motion grating activation. They also activated a region in the right fusiform gyrus that was more weakly activated by the motion grating. These results indicate that adding motion contrast to large moving fields increases activity in areas 17/18 and MT/MST and adds both dorsal and ventral regions that are similar for motion and luminance defined contours.

Adult↗
PubMed1998

Update: what is left for laparoscopic hernia repair?

The risks, benefits and costs of laparoscopic hernia repair are still being debated. According to a current survey on the situation of hernia surgery in Germany in 1996, laparoscopic hernioplasty was done in about 60% of the answering hospitals; about a quarter of all hernia repairs are done laparoscopically. Since April 1993, about 2, 700 laparoscopic hernia repairs were done at Marienhospital Stuttgart. The operating time was on the average 50 min. The rate of complications was about 3%. The postoperative period of disablement was a median of 20 days; included in this time was the postoperative hospital stay. The recurrence rate was about 1%. It is remarkable that laparoscopic hernia repair was equally efficient in repairing unilateral primary hernias, recurrent hernias or bilateral hernias. The cost analysis showed that the application of multipath articles will make the operation costs of laparoscopic hernia repair only about DM 100 higher than for a conventional operation.

Costs and Cost Analysis↗
PubMed1998

[Method of esthetic evaluation of the reconstructed breast after cancer. Report of 76 cases].

The authors propose a simple method of aesthetic evaluation of breast reconstructions after cancer, based on a 20-point score. In the 76 patients included in this study and mainly reconstructed by implant, the following seven criteria were evaluated by a score: the reconstructed breast, the symmetrized breast, symmetry of the 2 breasts, the areola, the nipple, the areolo-nipple complex (ANC) and the overall reconstruction. The first score was established during the visit by the patient and independently by the same plastic surgeon. The score was then established during two sessions of projection of standardized photographs, by two groups, A and B, composed of 9 nurses and secretaries and 10 plastic surgeons, respectively. Statistical analysis of the results showed that the scores for these criteria were all correlated for all examiners. This study confirms the reliability of aesthetic evaluation of breast reconstruction after cancer, by a group composed of 2 men and 2 women, surgeons or non-surgeons, on photographs or on clinical examination, based on a 20-point score.

Breast Neoplasms↗
PubMed1998

[Experience with the use of criteria for evaluating the need for hospitalization in a surgery department].

Acute hospital care is the most expensive form of medical care. Some of patients hospitalized in acute hospitals could be cared for in alternative settings without compromising quality of care. The Appropriateness Evaluation Protocol (AEP) is the most widely used tool for evaluation of appropriateness of hospitalisation in acute care hospitals. We applied AEP to 189 patients admitted within 20 days to department of surgery of a teaching hospital. We have evaluated appropriateness of admission and each following day of stay up till discharge or 15th day of hospitalization. Reasons of inappropriate admissions and delayed discharges were classified and analyzed. Results of the evaluation of selected patients were subject to control by a committee of fully specialized hospital physicians. 16 (8%) of 189 admissions and 306 (27.5%) of 1114 evaluated days of stay failed the AEP criteria. These patients could be well served by lower treatment intensity in outpatient clinics, nursery homes or their own homes. Such a shift in pattern of provided care requires profound organizational changes many of which are out of reach of individual acute hospitals. Despite some limitations we find AEP a useful tool for internal utilization review. External application of AEP in a representative sample of acute care hospitals could provide important data for future development of the Czech health care system.

Health Services Misuse↗