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Biomedical subjects

M Kiefer

Publications and source records attributed to M Kiefer.

At least 55 records · Page 3Linked to original sources
PubMed1998

The ependyma in chronic hydrocephalus.

H-Tx rats produce congenitally hydrocephalic offspring with varying severity of the condition. We used moderately hydrocephalic rats without evident clinical signs of hydrocephalus and normal controls from the same stock when they were at least 1.5 years old. Macroscopic anatomy was studied by MRI and in fixed brain slices and the ultrastructure of the ependyma, with REM. Apart from markedly stretched areas, where the ependyma was totally destroyed and subependymal structures directly exposed to the CSF, the density of ependymal microvilli and of tufts of cilia was reduced in proportion to the ventricular distension of a given area. A supraependymal "network"--never seen before in acute hydrocephalus--was found, whose purpose is probably to prevent further ventricular enlargement. We conclude that even in arrested hydrocephalus the ependymal sequelae of hydrocephalus are similar to those of the acute stage, illustrating the extremely limited potential for recovery, but the organism seems nevertheless to react with an internal stabilization of the ventricular system.

Animals↗
PubMed1997

Electrostatic effects in the kinetics of coenzyme binding to isozymes of alcohol dehydrogenase from horse liver.

The kinetic mechanism for the binding of NAD+ and NADH to the EE and SS isozymes of alcohol dehydrogenase (LADH) was studied between pH 7 and pH 10 by monitoring the quenching of tryptophan fluorescence. A consistent interpretation of all data was only possible by introducing a two-step binding mechanism. The first binding step is related to docking of the adenosine part of the coenzymes and the subsequent isomerization to the binding of the nicotinamide part. At high NADH concentrations an additional slow isomerization was identified as a conformational transition of the protein. A pH dependence for NADH binding is observed which is restricted to changes in the binding kinetics of the adenosine moiety going from pH 7 to pH 10, a tendency which is similar also for NAD+. This is attributed to pH-dependent variations in electrostatic attractions acting as a steering force of the docking process. The nicotinamide docking of NADH is equally fast for both isozymes and pH-independent over the measured range, whereas this docking equilibrium for NAD+ is pH-dependent for EE- and SS-LADH alike and the rate of association comparable. Presumably, a GluEE-366-LysSS substitution results in a stronger binding and faster association of both oxidized and reduced cofactor to the SS isozyme. A structural proof is presented for coenzyme-competitive binding of a sulfate ion, resulting in electrostatic shielding.

Alcohol Dehydrogenase↗
PubMed1996

[Incidence of postmyelography syndrome and postmyelography complaints after lumbar puncture with the Sprotte pencil-like needle in comparison with the Quincke needle].

PURPOSE: Myelography in combination with a postmyelography CT is an important presurgical examination because of its excellent visualisation of the disc, the bone and the contrast-filled dura. Side effects after myelography can be observed in up to 50% of patients. The pathophysiological mechanism is thought to be increased cerebrospinal fluid leakage at the puncture site. Since the introduction by Sprotte in 1979 of the pencil-point needle, a modification of Whitacre's needle, fewer complaints after lumbar puncture have been reported. The aim of the study was to examine the influence of two types of needle points and the temperature (37 degrees C vs 21 degrees C) of the contrast medium (CM; iotrolan, Isovist) on the incidence of side effects of lumbar puncture for myelography. MATERIAL AND METHODS: In a prospective randomized trial the incidence of complaints after lumbar puncture with intrathecal CM application was evaluated by the use of a 21-G pencil-point needle as modified by Sprotte compared to our usual 22-G needle with a Quincke bevel. Some 412 patients (201 female, 211 male; mean age 54.05 +/- 7.4 years) were investigated. Directly after examination and 1. 3 and 5 days later the patients were questioned about complaints (headache, neck stiffness nausea, vomiting, buzzing in the ear and dizziness). The results were tested by the chi square test. RESULTS: A significantly lower incidence of complaints was seen after lumbar puncture with the pencil-point needle/Quincke needle (headache: 6.3%/18.9%, P < 0.0001; headache lasting 3 days: 0.5%/7.8%, P < 0.0001; headache lasting 5 days: 0%/2.4%, P = 0.0305; nausea: 0%/4.9%, P = 0.0009; vomiting: 0%/3.4%, P = 0.0009; dizziness: 0%/3.4%, P = 0.0074; neck stiffness: 0%/3.4%, P = 0.0074). The temperature of the CM had no influence on the complaints. No influence was seen on the quality of the myelogram. No relation to sex and age was found. CONCLUSION: Complaints after lumbar puncture and myelography are caused by the cerebrospinal fluid leakage at the puncture site. The incidence of side effects related to this leakage can be reduced by using a pencil-point needle. The temperature of the CM has no influence on the complaints.

Adolescent↗
PubMed1996

Monitoring of exposure to benomyl in nursery workers.

We compared urinary levels of the metabolite methyl-5-hydroxy-2-benzimidazole carbamate (5-HBC) among nursery workers exposed to the fungicide benomyl (specifically Benlate 50 DF [DuPont, Wilmington, DE]) and workers not exposed to benomyl. Environmental exposures were quantitated from gloves, body patches, and air samples collected with area and personal monitors. The median concentration of 5-HBC in the urine of benomyl-exposed workers was 23.8 mumol of 5-HBC per mole of creatinine. No 5-HBC was detected in the reference group. Industrial hygiene results and biological monitoring findings indicate that use of Benlate 50 DF in the ornamental industry can lead to absorption of the active ingredient, benomyl. Weighing, mixing, and application activities involved the highest exposures. Dermal contact appeared to be the primary route of exposure.

Adult↗
PubMed1996

1-Hydroxypyrene levels in coal-handling workers at a coke oven.

An environmental and medical survey was conducted at the coal-handling area of a coke oven, where workers came in contact with coal-tar sludge. The purpose of the study was to determine if skin contact with coal-tar sludge was an important route of exposure to pyrene because workers were observed to have substantial contact with the sludge. Environmental monitoring revealed minimal airborne exposure to pyrene, a byproduct of the coke distillation process; only one personal breathing zone sample detected pyrene, and at least of 0.001 mg/m3. However, the mean preshift urinary 1-hydroxypyrene concentration was 1.00 mumol/mol creatinine (range, 0.16 to 2.96 mumol/mol creatinine) and the mean postshift level was 1.7 mumol/mol creatinine (range, 0.24 to 4.85 mumol/mol creatinine) (P < 0.01). These levels probably reflect absorption as a result of skin exposure.

Adult↗
PubMed1995

Outbreak of brucellosis at a United States pork packing plant.

In 1992, the North Carolina Department of Environment, Health, and Natural Resources received 18 case reports of brucellosis from a county health department. All patients had potential exposure to the kill floor of one pork processing plant. A subsequent National Institute for Occupational Safety and Health health hazard evaluation surveyed 154 (99%) of 156 kill floor workers of this plant and found that 30 (19%) had evidence of recent (or persistent) brucellosis. These data show that significant exposure to Brucella is occurring among packing plant workers in North Carolina and suggest that some of the approximately 38,000 production workers in pork processing plants in the United States are at risk of contracting swine brucellosis. Additional measures may need to be taken to prevent occupational exposure to Brucella.

Adult↗
PubMed1995

[Lumbar facet syndrome. Recommendation for staging before and after intra-articular injection treatment].

INTRODUCTION: Lumbar facet joint syndrome is normally based on spondylarthrosis. One of the most common methods of treating it is intra-articular injection of local anaesthetics and cortisone. In this prospective study our goal was to have an objective grading scale to assess the severity of lumbar facet syndrome before and after injection. METHODS: Thirty-two patients were treated by CT-guided intra-articular injections of 0.3 ml bupivacaine and 0.8 ml methylprednisolone. Five different parameters were scored in each patient: (1) finger-ground distance; (2) Schober index (10 cm distance along lumbar spine, difference in cm after flexion of lumbar spine); (3) rotation of lumbar spine; (4) lumbago; (5) pseudoradicular pain. The last two parameters were evaluated by a visual analog score (VAS) with zero for no pain and 10 for worst possible pain. Each parameter was evaluated with one, two or three points. After adding the points, we graded the severity of lumbar facet joint syndrome. RESULTS: Finger-ground distances improved statistically (P<0.05). Schober index and rotation of lumbar spine were not significant. VAS concerning lumbago and pseudoraducular pain were also statistically significant (P<0.001). Thirteen patients remained in the same grade, 18 patients improved by one grade and 1 patient by two grades. DISCUSSION: The grading system presented for assessing lumbar facet joint syndrome is a good parameter to evaluate the severity of the disease and follow-up after injection of local anaesthetics and cortisone. Although they showed no statistical significance, Schober index and rotation of lumbar spine are necessary to evaluate facet syndrome.

Bupivacaine↗
PubMed1994

Acute hydrocephalus as a late complication of hemispherectomy.

Two cases of acute hydrocephalus 34 and 27 years after hemispherectomy are presented. Both were examined by intracranial pressure recordings and treated with shunting procedures. The recordings gave evidence of raised baseline values of intracranial pressure and showed pathological B-wave activity in over 80% of the recording time. The problem of free communication between the different compartments after hemispherectomy and different surgical approaches to solve the problem are discussed. Open surgery is not advocated.

Adolescent↗
PubMed1992

[Environment and environmental medicine--an analysis of the population's need for advice].

Over a period of 6 months all inquiries related to environmental issues and environmental human health problems were recorded by the city administration (city phone, n = 71), the public health office (n = 123) and by pharmacies (n = 94). There was an institutional difference in the spectrum of the questions. Waste problems predominated at the city phone, questions related to nutrition at the pharmacies. More questions were raised by women, questioners were younger than the average population. The questions were based on own experience and on media reports to about the same extent. A relation to health complaints was presumed in 30% of the city phone calls, to about 50% at the pharmacies. Quality of the consultation was assessed by the advisors themselves.

Adult↗
PubMed1990

Isolation from adult human serum of four insulin-like growth factor (IGF) binding proteins and molecular cloning of one of them that is increased by IGF I administration and in extrapancreatic tumor hypoglycemia.

We have isolated four insulin-like growth factor binding proteins (IGFBPs) from adult human serum by insulin-like growth factor (IGF) I affinity chromatography and high performance liquid chromatography. A 36-kDa binding protein (BP), not digestible with N-glycanase, is increased in patients with extrapancreatic tumor hypoglycemia and during IGF I administration in healthy adults. Its 38 NH2-terminal amino acids are identical to those of an IGFBP sequence derived from a human cDNA that cross-hybridizes with the rat IGFBP-2 cDNA. With probes encoding a NH2-terminal, COOH-terminal, and a middle region of this protein we have obtained three cDNA clones from a Hep G2 cDNA library; one encodes human IGFBP-2, and the other two presumably represent unspliced heteronuclear and alternatively spliced mRNA, respectively. A 28-30-kDa IGFBP represents a novel BP species in human serum. Its 30 NH2-terminal amino acids are not homologous to IGFBP-1, -2, or -3. It is not digestible with N-glycanase and does not bind 125I-IGF I. The NH2-terminal sequences of a 42/45- and a 31-kDa IGFBP are identical to that of human IGFBP-3. The 42/45-kDa proteins are two glycosylation variants of BP-3. The 31-kDa protein presumably is a degradation product of BP-3 that lacks the COOH terminus. It is likely that the different IGFBPs modulate auto-/paracrine and endocrine effects of IGFs on growth and metabolism in a different and specific manner.

Adult↗
PubMed1990

Primary structure of the putative human oncogene, pim-1.

A full-length (6.1-kb) human genomic pim-1 gene, together with its immediate 5'-upstream promoter sequence (Ppim) was isolated and sequenced. The human pim-1 gene shares an overall nucleotide (nt) sequence identity of 53% with the previously reported murine pim-1 gene. It consists of six exons and five introns and contains a protein-coding region that is identical in nt sequence to a full-length human pim-1 cDNA. The gene codes for a predicted Pim-1 protein of 313 amino acids (aa) with an Mr of 35,690 and a pI of 5.7. The deduced aa sequence of the human Pim-1 has 94% identity with the murine Pim-1 whereas the nt sequences of the two genes are 88% identical. All of the conserved aa residues of the mouse pim-1 gene, which are homologous to known protein kinases are conserved in the predicted human protein. The human Ppim region is very G + C-rich (69%) and shares greater than 80% identity with the murine Ppim. The Ppim has no TATA- or CAAT-box sequences but does contain a number of nt sequences similar to the putative binding sites of several presumptive transcription factors.

Amino Acid Sequence↗
PubMed1987

Molecular, cellular, and functional properties of bone marrow T lymphocyte progenitor clones.

The continuous proliferating bone marrow clones C4-77, C4-86, and C4-95 express low levels of Thy-1 and Ly-1 surface antigens, but no detectable surface antigens normally present on thymocytes, peripheral mature T lymphocytes, cells of the B lymphocyte or myeloid lineages. They contain the T cell antigen receptor genes alpha, beta, and the T cell-specific gene gamma in the germline configuration, and they express functional receptors for IL-3 and nonfunctional receptors for IL-2. The C4 clones are able to home and undergo differentiation in the thymus of sublethally irradiated mice and give rise in vivo to phenotypically and functionally mature peripheral T lymphocytes displaying several antigen specificities. In vitro 5-Azacytidine induces the C4 clones to express Lyt-2 and L3T4 T cell differentiation antigens, and renders them amenable to be switched from IL-3 to IL-2 dependence. However, the C4 clones seem incapable of giving rise to B lymphocytes either in vivo or in vitro. They self-renew in vitro in the presence of IL-3 every 12-14 h. We conclude that the C4 clones represent cells at the earliest stage of T cell development, i.e., Pro-T lymphocytes.

Animals↗