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Biomedical subjects

M Lange

Publications and source records attributed to M Lange.

At least 109 records · Page 6Linked to original sources
PubMed1996

The challenge of fall prevention in home care: a review of the literature.

Two thirds of accidents of people older than 65 years are due to falls, and a large proportion of death due to injury in the elderly can be traced to falls. Caring for people in their home environment allows home care nurses to have a pivotal role in the assessment of risk factors for falls and in the implementation of interventions that address primary, secondary, and tertiary activities that can prevent falls from occurring. This article provides an extensive review of the literature regarding falls and outlines successful clinical nursing interventions that can be used to prevent falls.

Accidental Falls↗
PubMed1996

Adherence, fibronectin binding, and induction of cytoskeleton reorganization in cultured human cells by Mycoplasma penetrans.

Mycoplasma penetrans adhered to cultured human cells, forming clusters that localized to specific areas of the host cell surface. Adherence and cluster formation were inhibited by anti-M. penetrans antibodies, suggesting the involvement of specific adhesin-receptor interactions. Ultrastructural studies showed that after 2 h of infection, mycoplasmas attach to and penetrate the host cell surface. M. penetrans bound selectively to immobilized fibronectin, an interaction which was not inhibited by a 70-kDa fragment containing a heparin-gelatin-binding domain of fibronectin, other matrix glycoproteins, or an RGD tripeptide, suggesting the recognition of other specific binding sites on the fibronectin molecule. A ca. 65-kDa fibronectin-binding protein of M. penetrans was eluted following Sepharose-fibronectin affinity chromatography. Confocal, light, and immunofluorescence microscopy demonstrated that the interaction of M. penetrans with target cells triggers a signal that causes recruitment of several cytoskeletal components, including tubulin and alpha-actinin, and aggregation of phosphorylated proteins. Detergent-soluble mycoplasma proteins with apparent molecular masses of 18, 28, 32, 36, 39, and 41 kDa selectively bound to glutaraldehyde-fixed HEp-2 cells. Our findings offer new insights into understanding the interaction of this human mycoplasma with host target cells.

Adhesins, Bacterial↗
PubMed1996

Effects of sho-saiko-to on production of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and superoxide from peripheral monocytes and polymorphonuclear cells isolated from HIV infected individuals.

The effects of Sho-saiko-to (SST), a traditional Chinese medicine, on the production of PGE2 from monocytes, LTB4 and superoxide from polymorphonuclear cells (PMNC) in HIV infected individuals were studied. SST inhibited the production of PGE2 from monocytes stimulated by opsonized zymosan in all groups including the healthy control group and also inhibited the production of superoxide from PMNC after stimulation with FMLP. On the other hand, SST enhanced the production of LTB4 when PMNC were stimulated by the calcium ionophore A23187. These results suggest that SST has different effects on the production of prostanoids or superoxide from monocytes and PMNC. Furthermore, our data indicates that inhibition of PGE2 or superoxide production will lead to indirect suppression of HIV, and enhancement of LTB4 will contribute to the upregulation of the immune reaction in HIV infected individuals.

Dinoprostone↗
PubMed1995

A simulation study of estimators for rates of change in longitudinal studies with attrition.

Many longitudinal studies and clinical trials are designed to compare rates of change over time in one or more outcome variables in several groups. Most such studies have incomplete data because some patients drop out before completing the study. The missing data may induce bias and inefficiency in naive estimates of important parameters. This paper uses Monte Carlo methods to compare the bias and efficiency of several two-stage estimators of the effect of treatment on the mean rate of change when the missing data arise from one of four processes. We also study the validity of confidence intervals and the power of hypothesis tests based on these estimates and their standard errors. In general, the weighted least squares estimator does relatively well, as does an analysis of covariance type estimator proposed by Wu et al. The best estimates of variance components are based on complete cases or maximum likelihood.

Analysis of Variance↗
PubMed1995

Interplay between mycoplasmas and host target cells.

The infectious pattern of mycoplasmas (Mycoplasma penetrans, Mycoplasma pneumoniae and Mycoplasma genitalium) in mammalian cells was examined using confocal microscopy and flow cytometry combined with cell fractionation and mycoplasma viability determinations. Within 2 h postinfection mycoplasmas parasitize cell surfaces, enter the intracellular spaces and locate throughout the cytoplasmic and perinuclear regions. These mycoplasmas can be cultivated from cytoplasmic and nuclear fractions 96 h later and continue to persist intracellularly for at least 7 days, suggesting a much more active intracellular role for mycoplasmas than had been considered previously.

Animals↗
PubMed1995

Intracavitary treatment of intrasellar cystic craniopharyngeomas with 90-Yttrium by trans-sphenoidal approach--a technical note.

Intracavitary irradiation of intrasellar cystic craniopharyngeomas by stereotactic cyst puncture and injection of radioactive solutions is not yet possible. Therefore we designed a new method which allows such intracavitary irradiation. Its principle is a transphenoidal approach with only a small bony opening of the sella floor, followed by cyst puncture, exclusion of cyst leakage by Metrizamid injection under x-ray control, injection of Y-90-colloid solution at a dosage which delivers a radiation of 200 Gy to the cyst wall, and finally tight closure of the puncture site using fibrin glue and gelfoam. This method has been used in three patients with good results (follow-up 12-15 months) and without complications. Even though long-term follow-up is not yet available, our preliminary results suggest that this method will be useful for future patients with intrasellar cystic craniopharyngeomas.

Adolescent↗
PubMed1995

Influence of electron scavengers on the radical formation in thymidine-5'-monophosphate and DNA in frozen aqueous solution and glasses.

Structural and quantitative effects of different electron scavenger concentrations on the free radical formation in the nucleotide thymidine-5'-monophosphate (TMP) and in deoxyribonucleic acid (DNA) after X-irradiation in frozen aqueous solution and glasses (BeF2/H2O for TMP and LiCl/H2O for DNA) at 77K are investigated. At the highest concentration used (100 mmol dm-3) about 80% (TMP) and 70% (DNA) of the radicals are scavenged compared with the control in both matrices. In TMP, allyl radicals form the major population of radicals left unscavenged at 77 K. These are shown to transform into a quintet pattern upon annealing (> or = 220 K). Analysis of various substances for quintet formation shows that a sugar-group and a C4-carbonyl group are necessary structural prerequisites. For DNA three components can be extracted from spectra obtained with different scavenger concentration in frozen solutions. There are two components in LiCl glasses, which are comparable with two of the three in frozen aqueous solution. Their potential origin is discussed in comparison with nucleotide spectra.

Chlorides↗
PubMed1995

Expression and localization of endothelin-1 and endothelin receptors in human meningiomas. Evidence for a role in tumoral growth.

In addition to its well-known homoeostatic actions in the cardiovascular system, ET-1 has been shown to constitute a potent growth regulatory peptide in various tissues. We have studied the expression of ET-1 and its receptors (ET-Ar and ET-Br) in human meningiomas (n = 35) as well as their involvement in cellular growth. By PCR of reverse-transcribed RNA we detected ET-1 mRNA in 91% (32 of 35), ET-Ar mRNA in 82% (29 of 35), and ET-Br mRNA in 42% (15 of 35) of human meningiomas examined. The localization of ET-1 mRNA, ET-Ar mRNA, and ET-1 peptide in tumoral cells was observed by in situ hybridization and immunohistochemistry, whereas ET-Br mRNA was expressed at low level only in cells belonging to blood vessels. In addition, we found that ET-1 stimulated [3H] thymidine incorporation in primary cell cultures of 20 meningiomas and that this effect could be blocked by BQ-123, a specific antagonist for ET-Ar. In contrast, RES-701-3, an antagonist of ET-Br, did not block the proliferative effect of ET-1. In conclusion, our data provide evidence that ET-1 constitutes an important growth factor for meningiomas acting via ET-Ar. We can hypothesize that ET-1, acting in concert with other growth factors and cytokines, is involved in the meningioma tumorigenesis.

Adult↗
PubMed1994

Fast method for the simultaneous determination of 2-oxo acids in biological fluids by high-performance liquid chromatography.

A fast and sensitive method for the single-run quantification of various 2-oxo acids including 2-ketoglutarate, glyoxylate and pyruvate is described. It ensures good separation of peaks with minor interference by other substances. The 2-oxo acid derivatives are measured photometrically at 324 nm after derivatization with phenylhydrazine and subsequent isocratic separation with ethanolic phosphate buffer on a C18 reversed-phase HPLC column. Recovery was found to be complete [range: 96.3 +/- 5.6% (pyruvate) to 104.8 +/- 5.2% (2-ketoglutarate)]. Detection limits ranged from less than 0.1 mumol/l (glyoxylate) to 0.25 mumol/l (2-ketoglutarate and pyruvate). Results for all substances examined showed good linearity with correlations (r2) of equal to or better than 0.998.

Chromatography, High Pressure Liquid↗
PubMed1994

Genetic heterogeneity of severe von Willebrand disease type III in the German population.

The genetic heterogeneity of severe von Willebrand disease (vWd) type III was estimated by analysing extended haplotypes of eleven intragenic restriction fragment length polymorphisms and one variable number of tandem repeat polymorphism in 32 patients from 28 families from Germany or of German origin. All patients were screened for gross deletions and for mutations at potential "hot spot" regions of the von Willebrand factor (vWf) gene. Disease-associated haplotypes were established in 24 families. Only a few, apparently unrelated families shared common haplotypes suggesting a considerable genetic heterogeneity in the German population of vWd type III patients. Defects causing vWd type III were identified on 14 out of 56 chromosomes (25%). Gross deletions were detected in two families. A complete homozygous deletion of the vWf gene was displayed in one patient. Another patient was compound heterozygous for a large deletion of at least 100 kb of the vWf gene with an additional, as yet unidentified, defect. One homozygous missense mutation was detected in exon 10, and two nonsense mutations were detected in exon 8 and exon 45 of the vWf gene, respectively. A frameshift mutation (delta C) in exon 18 was identified in five families and an additional frameshift mutation (delta G) was found in exon 28 in one family. It appears that delta C is the most common molecular defect in German patients with vWd type III. Its association with a number of different haplotypes suggests repeated de novo mutations at a mutation "hot spot". Evidence is presented that particular molecular defects causing vWd type III are associated with different patterns of inheritance, depending on their location within the vWf gene. Complete deletions of the gene and nonsense mutations in the pro-sequence are correlated with recessive inheritance, whereas frameshift and nonsense mutations in the gene sequence corresponding to the mature vWf subunit tend to be inherited in a dominant fashion.

Adolescent↗
PubMed1994

Growth hormone (GH)-releasing peptide stimulation of GH release from human somatotroph adenoma cells: interaction with GH-releasing hormone, thyrotropin-releasing hormone, and octreotide.

The synthetic hexapeptide GH-releasing peptide (GHRP; His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) specifically stimulates GH secretion in humans in vivo and in animals in vitro and in vivo via a still unknown receptor and mechanism. To determine the effect of GHRP on human somatotroph cells in vitro, we stimulated cell cultures derived from 12 different human somatotroph adenomas with GHRP alone and in combination with GH-releasing hormone (GHRH), TRH, and the somatostatin analog octreotide. GH secretion of all 12 adenoma cultures could be stimulated with GHRP, whereas GHRH was active only in 6 adenoma cultures. In GHRH-responsive cell cultures, simultaneous application of GHRH and GHRP had an additive effect on GH secretion. TRH stimulated GH release in 4 of 7 adenoma cultures; in TRH-responsive cell cultures there was also an additive effect of GHRP and TRH on GH secretion. In 5 of 9 adenoma cultures investigated, octreotide inhibited basal GH secretion. In these cell cultures, GHRP-induced GH release was suppressed by octreotide. In 5 of 5 cases, the protein kinase-C inhibitor phloretin partly inhibited GHRP-stimulated GH release, but not basal GH secretion. In summary, GH secretion was stimulated by GHRP in all somatotroph adenomas investigated, indicating that its unknown receptor and signaling pathway are expressed more consistently in somatotroph adenoma cells than those for GHRH, TRH, and somatostatin. Our data give further evidence that GHRP-stimulated GH secretion is mediated by a receptor different from that for GHRH or TRH, respectively, and that protein kinase-C is involved in the signal transduction pathway. Because human somatotroph adenoma cell cultures respond differently to various neuropeptides (GHRH, TRH, somatostatin, and others), they provide a model for further investigation of the mechanism of action of GHRP-induced GH secretion.

Adenoma↗
PubMed1994

Endothelin expression in normal human anterior pituitaries and pituitary adenomas.

Endothelins (ETs) are important regulators of growth and function in many endocrine tissues. This study was designed to verify the expression of ETs in a series of normal human pituitaries and pituitary adenomas. We examined 13 normal pituitaries and 58 pituitary adenomas for the presence of immunoreactive (ir) ET-1 and ET-3. No ir-ET-1 was detected in any of the 13 normal pituitaries, whereas ir-ET-3 was observed in 4 of 13 (31%) cases. In contrast, 48% (28 of 58) of pituitary adenomas display immunoreactivity for ET-1, whereas 31% (18 of 58) show immunoreactivity for ET-3. With respect to the type of tumors, staining was as follows: nonfunctioning adenomas: ET-1, 14 of 33; ET-3, 9 of 33; somatotropinomas: ET-1, 8 of 16; ET-3, 6 of 16; corticotropinomas: ET-1, 5 of 5; ET-3, 2 of 5; and prolactinomas; ET-1, 1 of 4; ET-3, 1 of 4. Using double immunostaining, we found the colocalization of ET-3 in normal pituitaries and of ET-1 and ET-3 in pituitaries adenomas in each hormone-secreting cell. In Cushing adenomas, ET-1 was coexpressed in corticotropic cells in all 5 cases (100%). In the same tumors, by reverse transcriptase polymerase chain reaction, we investigated the presence of ET-1 and ET-3 messenger ribonucleic acids and found that they are expressed, respectively, in 18 of 21 and 7 of 11 tumors examined. Our findings demonstrate that pituitary adenomas frequently display ET-1 as well as ET-3 immunoreactivity, in contrast to normal pituitaries, in which only ET-3 was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1994

Effect of bromocriptine and SMS 201-995 on growth of human somatotrophic and non-functioning pituitary adenoma cells in vitro.

The effect of the dopamine agonist bromocriptine and the somatostatin analog SMS 201-995 on growth of 12 human somatotrophic and 13 non-functioning adenoma cell cultures was investigated. When adenoma cells were maintained in medium supplemented with 5% fetal calf serum, cell counts of 10 of 12 somatotrophic cultures increased to 145 +/- 6 and 171 +/- 9% (mean +/- SD) and in 12 of 13 non-functioning cell cultures up to 125 +/- 12 and 217 +/- 15% after 3 days of incubation. In most cases bromocriptine and SMS 201-995 dose dependently (1 nmol/l to 10 mumol/l) inhibited adenoma cell growth but there was only (1, 10 mumol/l) a significant inhibitory effect at high doses of both drugs. A 1 mumol/l concentration of bromocriptine decreased cell counts of 5 of 12 somatotrophic cell cultures (range 84 +/- 3 to 76 +/- 6% vs control = 100%) and in 5 of 13 non-functioning cell cultures (range 85 +/- 4 to 71 +/- 7%). A 10 mumol/l concentration of bromocriptine decreased cell counts in all 12 somatotrophic (range 87 +/- 1 to 61 +/- 8%) and in 12 of 13 non-functioning adenoma cultures (range 87 +/- 6 to 57 +/- 3%). Bromocriptine specifically inhibited growth because its effect could be reversed by the dopamine D2-receptor antagonist haloperidol. Both 1 and 10 mumol/l SMS 201-995 significantly decreased cell counts in three of six somatotrophic (87 +/- 3 to 38 +/- 3%) cell cultures. In two of five cases growth of non-functioning adenoma cultures was suppressed by 1 mumol/l SMS 201-995, and in four of five cases by 10 mumol/l (86 +/- 3 to 74 +/- 4%). The growth inhibitory effect of both bromocriptine and SMS 201-995 was not just due to an effect on growth of fibroblasts contaminating the adenoma cell cultures, because it could be observed also when adenoma cells were maintained in a D-valine-supplemented medium that suppresses fibroblast growth. In summary, both bromocriptine and SMS 201-995 at high doses were able to inhibit cell growth of cultured somatotrophic and non-functioning adenomas in vitro. However, the mechanism of this inhibitory effect is not yet well understood.

Adenoma↗
PubMed1994

Intraduct carcinoma of the breast (duct carcinoma in situ).

A retrospective study of non-invasive ductal carcinoma in situ in a series of women is presented. The epidemiology, clinical characteristics and results in 65 patients treated by mastectomy or breast-conserving surgery, with or without radiation therapy, are reported. The significant recurrence rate and high proportion of invasive cancers among patients with recurrences are noted. Recurrences were more frequent in patients with larger tumours and those with comedo-type intraduct carcinomas. Implications and guidelines for therapy are presented.

Adult↗
PubMed1994

Tumour kinetics in breast cancer.

In vivo bromodeoxyuridine was used to measure the 'bromo' labelling index (LI,%), the duration of the S-phase (Ts, hours) and the potential tumour doubling time (Tpot, days) in women with stages I-IV breast cancer. These were studied in relation to lymph node status, tumour size, histological grade, oestrogen receptor status (ER), ploidy and S-phase fraction (SPF). In our patients, a LI of 10%, a Tpot of 2 days or an SPF of 9-10.5% predicted aggressive breast cancer. The LI was significantly higher (5%) in ER-negative than in ER-positive (2%) tumours (P = 0.03). There was a trend towards increased DNA synthesis in cancers with an SPF over 10% (P = 0.08). ER-negative breast cancers over 2 cm in diameter had shorter median Tpots of 5.3 days (P = 0.02) and 8 days (P = 0.05) compared with smaller, ER-positive tumours. A trend towards faster growth rates was seen in lymph node-positive, high-SPF (> 10%) breast cancers. Tumour kinetics may have additional prognostic value in the selection of node-negative patients for adjuvant therapy.

Breast Neoplasms↗
PubMed1994

Improved determination of small amounts of free hydroxyproline in biological fluids.

A fast, reliable, and sensitive (< 20 pmol) method for the quantification of 4-hydroxyproline is described. It ensures good separation of imino acid peaks, eliminates interference by primary amino acids, and guarantees full (96-105%) recovery of hydroxyproline (HYP). Interfering primary amino acids are derivatized by o-phthaldialdehyde and removed from the sample by use of a discardable C18 column. HYP is measured photometrically at 254 nm after a second derivatization with phenylisothiocyanate and isocratic separation on a reversed-phase HPLC column.

Chromatography, High Pressure Liquid↗
PubMed1993

Surgical treatment and results in patients suffering from lumbar spinal stenoses.

Stenosis of the lumbar spinal canal is contributing to 3-5% of all patients operated on a lumbar nerve root compression syndrome. Morphologically, a reduction of the midsagittal diameter of the spinal canal to less than 12 mm or stenoses of the lateral recessus or foramen intervertebrale have been described. In our department 37 patients with a lumbar spinal stenosis have been surgically treated between 1982 and 1987. Spinal stenosis is a disease of aged patients mostly suffering for a long history. The main symptoms are lumbar and sciatic pains, neurological deficits and a claudicatio intermittens spinalis. Neuroradiologically, the diagnosis can be confirmed by CT, myelography or MRI. These studies were demonstrating the stenosis in 69% at the level of L4/5, multiple stenoses have been found in 22% of all cases. An additional disc herniation existed in 35% of the patients. Concerning the specific complaints of the patients and their neuroradiological findings, the extent of the surgical decompression was decided on individually in each patient. We performed 22 laminectomies, 11 hemilaminectomies, in 3 cases an extended flavectomy and in one case an implantation of a dorsal column stimulation device. The postoperative follow-up period, ranging from 3 months to 3 years, demonstrated a complete recovery in 53%, a marked reduction of complaints in 44% of all cases. One patient did not respond to surgical treatment, but in the remaining cases surgical treatment led to satisfactory results.

Aged↗