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Biomedical subjects

W Meissner

Publications and source records attributed to W Meissner.

At least 37 records · Page 2Linked to original sources
PubMed2000

The effect of impulse noise exposure on distortion product otoacoustic emissions in the awake guinea pig.

Distortion product otoacoustic emissions (DPOAE) are a sensitive detector of outer hair cell (OHC) function and were monitored in awake guinea pigs before and after impulse noise damaging the cochlea (peak intensity 153 dB SPL, rise time < 0.1 ms). Animals had stable DPOAE levels before noise exposure. In the first hours after noise exposure DPOAE levels were reduced significantly. Three different patterns of recovery of DPOAE were seen in the post-exposure period:restitution exceeding controls, partial recovery and no recovery. In general, DPOAE levels declined and types of recovery closely corresponded to changes in amplitudes of cochlear microphonics after noise exposure. These data suggest that the monitoring of DPOAE is a suitable method for diagnosing impaired OHC function.

Animals↗
PubMed1999

[Influence of the degree of carbohydrate metabolism imbalance in gestational diabetes on pregnancy and newborns condition].

UNLABELLED: The aim of our study was the evaluation of the correlation between carbohydrate metabolism imbalance at the moment of gestational diabetes mellitus (GDM) diagnosis and regulation of glycemia during pregnancy, pregnancy complications, time and mode of delivery and conditions of the newborns. MATERIAL: 231 women with GDM delivered in our hospital between 1993-1996 were investigated. This population was divided into 6 groups, according to glycemia levels. METHOD: The term of diagnosis of the GDM, medical treatment (diet or diet and insulin), the degree of metabolic regulation archived, mode and time of delivery, as well as state of newborns were analysed. RESULTS: In groups I and VI we noticed the greatest percentage of patients treated with insulin (68%, 67%), versus 26% in group II and 17% in group III. In group VI in all cases treated with insulin we begun this therapy shortly after marking GDM. Glycemia in 24 hrs period after GDM diagnosis in group I were 122.7 +/- 28.6 mg/dl, in group VI 112.0 +/- 23.6 mg/dl, while we noticed 90.3 +/- 15.6 mg/dl in group II and 87.7 +/- 15.9 mg/dl in group III. Blood glucose level < 100 mg/dl in first determination of 24 hrs profiles we noticed in 5% in group I, 2% in group VI while 20% in group II and 51% in group III. Average levels of glycemia in last 24 hrs profiles before delivery in group I were 93.0 +/- 15.8 mg/dl, in group VI 96.2 +/- 21.1 mg/dl while 87.8 +/- 13.5 mg/dl in group II and 86.8 +/- 14.1 mg/dl in group III. Blood glucose level < 100 mg/dl of daily profile before the end of pregnancy was discovered in 8% in group I, 47% in group III. The greatest amount of complications (pregnancy induced hypertension and imminent premature delivery) was diagnosed in group VI-75% and in group III-55%. Surgical delivery took place in group I in 50%, in group V in 46%, in group VI in 67% while 17% in group II, 35% in group III and 30% in group IV. Macrosomy of newborns (> 4000 g) was diagnosed in group I in 36% in group V in 23% and in group VI in 42% while 9%, 6% and 15% in groups, II, III and IV respectively. The condition of newborns in the 1st minute of life was determined as good (8-10 points in Apgar scale) in significant percentage, in 87%, 75%, 70% in groups II, III, IV while only 59%, 62%, 58% in groups I, V, VI respectively. CONCLUSION: Serious intensification of carbohydrates metabolism disorders at the moment of diagnosing GDM, such as fasting glycemia > 140 mg/dl and the result after 2 hours > 200 mg/dl in 75 g OGTT more often requires insulin treating connect with numerous difficulties both in pregnancy monitoring and also has inadventageous influence on obstetrics outcomes-increasing percentage of surgery deliveries and macrosomies, that change the condition of newborns for worse.

Adult↗
PubMed1998

Reorganization of the somatosensory cortex after amputation of the index finger.

Cortical reorganization occurs within the primary somatosensory and the primary motor cortex after amputation of the arm or forearm. Here we report on a patient showing cortical reorganization after amputation of his right index finger. Our findings indicate that the neural networks within the area of the amputated finger in the somatosensory cortex (SI) were invaded by neighbouring structures, i.e. of neural cell assemblies that subserve the thumb and middle finger of his right hand.

Amputation, Traumatic↗
PubMed1997

On-demand analgesia with piritramide in children. A study on dosage specification and safety.

The results of this study show that postoperative patient-controlled pain therapy in children with piritramide is - in a similar way as with adults - a safe method involving a low incidence of side effects. A special pump parameter setting is required with larger bolus dose sizes and longer lockout intervals, not very different from the experience gained with adults, and which is based on other values than those recommended up to now with morphine for paediatric PCA. Side effects were rarely observed. The fear of respiratory depression constitutes no rational reason to deny the younger patients this form of analgesia provided that monitoring is guaranteed.

Adolescent↗
PubMed1997

[Loop ileostomy--use and results].

Loop ileostomy (LI) is created to obtain a complete diversion of feces with defunctioning of the distal colon. LI can be temporary or permanent for palliative reasons. The purpose of this study was to assess the morbidity related to LI created at our Institution between 1985 and 1996 in 135 patients. According to the results of the study and the review of the literature, the authors conclude that LI is a simple and safe method, providing an effective fecal diversion. LI should be the procedure of choice if the risk of bowel suture line complications is expected.

Adolescent↗
PubMed1997

[Surgical procedure in fulminant colitis and toxic megacolon].

Both fulminant colitis and toxic megacolon are regarded as the sequelae of colitis in which irreversible changes in the whole thickness of colonic wall have occurred. These condition both call for an immediate, emergent surgical intervention. Until recently the procedure of choice in this acute phase of the disease was colectomy with Brooke ileostomy and Hartmann type closure of the distal rectum. Colectomy with ileal pouch anal anastomosis was reserved only for elective surgery. The improvement in surgical technique, but first of all widespread of stapling devices, have shortened the time of operation and simplified the procedure, so that creation of an ileal reservoir is currently more often performed as a one step procedure and without an increased risk. Between 1985 and 1997 in our Department, 120 patients had ileal pouches created for various conditions. There were 72 patients with ulcerative colitis in this series and 10 of them had-one-step procedure involving pouch formation in the acute phase of the disease. Multi-step procedures, including Hartmann's colectomies were performed in 16 patients. One-step operations involving ileal pouch creation in the acute phase of the ulcerative colitis are feasible in selected cases and in experienced centres. Such an approach shortens the time of treatment.

Colitis↗
PubMed1997

[Glycemia control in diabetic pregnancies under intensive insulin treatment with and without the aid of the Camit-Diacomp system].

The efficiency of glycemia control was compared in two groups of insulin dependent diabetic pregnancies treated with insulin, with and without the aid of the Camit-Diacomp system. The efficiency of glycemia control was analysed in all three trimesters of pregnancy. Mean diurnal fluctuations of glycemia levels in both study groups were compared. The clinical state of newborns, their glycemia and insulin levels in cord blood were analysed as well. No statistically significant differences of glycemia levels between the two compared groups of patients were found, however the observed significant differences of the HbA1C levels between these groups can speak in favour of the efficiency of treatment under the Camit-Diacomp system, which enables a more precise self control of the treatment and dosage of insulin.

Circadian Rhythm↗
PubMed1995

Pharmacokinetics of intranasal alfentanil.

STUDY OBJECTIVE: To determine the pharmacokinetics of intranasal and intravenous (IV) administrations of alfentanil in 10 healthy volunteers. DESIGN: Randomized, prospective, double-blind, placebo-controlled, cross-over trial with at least one week between the two modes of administration. SETTING: Healthy volunteers at a university medical center. SUBJECTS: 10 healthy, nondrug-dependent volunteers. INTERVENTIONS: Alfentanil 0.54 mg was administered either intranasally [with 12 ml of sodium chloride (NaCl) 0.9% IV] or IV (with 12 sprays of NaCl 0.9% intranasally). Each subject was assigned once to the intranasal and once to the IV group. To guarantee a complete elimination of alfentanil, there was a time period of at least one week between the different modes of administration. MEASUREMENTS AND MAIN RESULTS: Venous blood was sampled from a cubital vein at 3, 6, 9, 12, 15, 20, 30, 60, and 120 minutes after administration. Alfentanil plasma concentrations were determined by radioimmunoassay. Maximal plasma concentrations were 20.1 ng/ml +/- 7.3 ng/ml after 9 minutes in the intranasal group. At this measurement point, the intranasal alfentanil concentrations were 64.7% (18.7 ng/ml +/- 6.8 ng/ml) of the IV concentrations (28.9 ng/ml +/- 7.9 ng/ml). The calculated bioavailability after intranasal administration was 64.96% +/- 26.3%. CONCLUSIONS: This pharmacokinetic study demonstrates a rapid rise in plasma concentrations, as well as a high bioavailability, following the intranasal administration of alfentanil.

Administration, Intranasal↗
PubMed1995

The activity of transcription factor PBP, which binds to the proximal sequence element of mammalian U6 genes, is regulated during differentiation of F9 cells.

Mouse F9 embryonic carcinoma (EC) cells differentiate in culture to parietal endoderm (PE) cells upon induction with retinoic acid and cyclic AMP. In the course of this process, the expression of polymerase III transcripts, e.g., 5S rRNA and U6 small nuclear RNA, is dramatically reduced. This reduction of endogenous RNA content is accompanied by a loss of transcriptional capacity in cell extracts from PE cells. Partial purification of such extracts reveals that the DNA-binding activity of transcription factor PBP, binding specifically to the proximal sequence element (PSE) sequence of vertebrate U6 genes, is significantly reduced. This finding is corroborated by a loss in the transcriptional activity of this factor in reconstitution assays with partially purified polymerase III transcription components. In contrast, the activity of TFIIIA and TFIIIB and the amount of free TATA-binding protein remain unchanged during the differentiation process analyzed here. These data show for the first time that the PSE-binding protein PBP is essentially involved in the differential regulation of polymerase III genes governed by external promoters.

Animals↗
PubMed1994

Isolation of transcription factor IIIC from Dictyostelium discoideum.

Transcription factor IIIC (TFIIIC) binds in a sequence-specific manner to RNA-polymerase-III-transcribed genes (e.g. tRNA genes). It sequesters other transcription factors into the preformed complex, thereby activating transcription by RNA polymerase III. The Dictyostelium discoideum homologue of TFIIIC was highly purified by affinity chromatography based on its tDNA-binding activity. This TFIIIC homologue is a multicomponent factor (molecular mass 380 kDa), which binds to the B-box element of the internal tRNA gene promoter without significant A-box interaction. Partially purified D. discoideum TFIIIC is able to functionally complement a human RNA polymerase III in vitro transcription system depleted of human TFIIIC. We provide evidence that partially purified D. discoideum TFIIIC interacts in vitro with gene-external B-box elements present down-stream of many D. discoideum tRNA genes.

Animals↗
PubMed1994

Transcription factors required for the expression of Xenopus laevis selenocysteine tRNA in vitro.

It has previously been reported that transcription in vivo of the tRNA(Sec) gene requires three promoter elements, a PSE and a TATA-box upstream of the coding region which are functionally interchangeable with the U6 snRNA gene counterparts and an internal B-block, resembling that of classical tRNA genes (1). We have established an in vitro transcription system from HeLa cells in which three factors, which are either essential for or stimulate transcription were identified. Apart from the TATA-binding protein TBP, the PSE-binding protein PBP was found to be essentially required for expression of the gene. Depletion of PBP from cell extracts by PSE-oligonucleotides abolished tRNA(Sec) transcription, which could be reconstituted by readdition of partially purified PBP. Addition of increasing amounts of recombinant human TBP to an S100 extract stimulated transcription of the tRNA(Sec), the mouse U6 snRNA and the human Y3 genes, an effect which was not observed in the case of a TATA-less tRNA gene. Purified human TFIIA strongly stimulated tRNA(Sec) transcription in a fashion depending on the concentration of TBP. Surprisingly, partially purified TFIIIC was shown to be dispensable for transcription in vitro and unable to bind the B-block of this gene in vitro, although its sequence matches the consensus for this element. Collectively, these data suggest that the mechanism by which transcription complexes are formed on the tRNA(Sec) gene is dramatically different from that observed for classical tRNA genes and much more resembles that observed for externally controlled pol III genes.

Animals↗
PubMed1994

[Detection of inactivity of the auditory system in the beginning stage with the Freiburg masked speech test].

Late-onset auditory deprivation or "inactivity" phenomenon has been reported in single cases only because it has not been possible to assemble a larger number of calculable cohorts for which all necessary details concerning individual histories are available. Subjects should not be older than 60 years of age and should have had asymmetric hearing for at least about 10 years or should have been wearers of monaurally fitted hearing aids. The development of late-onset auditory deprivation is presented in 6 single cases. All were assessed by the Freiburg speech discrimination test and the distorted Freiburg speech test, with the latter showing greater sensitivity and variability. It is of special interest that the quotient of distorted speech is reduced in subjects who have normal hearing in one ear and considerable hearing loss in the other ear (for example, in the case of unilateral microtia). This effect may be evidence for significant activation of hearing selectivity developing in the brainstem versus inactivation.

Adolescent↗