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Biomedical subjects

K Rohde

Publications and source records attributed to K Rohde.

At least 73 records · Page 4Linked to original sources
PubMed1994

The use of loss of constitutional heterozygosity data to ascertain the location of predisposing genes in cancer families.

A method is described to investigate the inheritance of disease predisposition in cancer families. It is an extension of classic genetic linkage analysis, which enables information on loss of constitutional heterozygosity (LOCH) to be incorporated into the model. This adapted model treats LOCH data as additional observations on the disease phenotype. One of the major benefits of this approach is that isolated parent-offspring pairs are now potentially informative for linkage analysis. Examples are presented.

Alleles↗
PubMed1994

Detection of a major gene for heterocellular hereditary persistence of fetal hemoglobin after accounting for genetic modifiers.

"Heterocellular hereditary persistence of fetal hemoglobin" (HPFH) is the term used to describe the genetically determined persistence of fetal hemoglobin (Hb F) production into adult life, in the absence of any related hematological disorder. Whereas some forms are caused by mutations in the beta-globin gene cluster on chromosome 11, others segregate independently. While the latter are of particular interest with respect to the regulation of globin gene switching, it has not been possible to determine their chromosomal location, mainly because their mode of inheritance is not clear, but also because several other factors are known to modify Hb F production. We have examined a large Asian Indian pedigree which includes individuals with heterocellular HPFH associated with beta-thalassemia and/or alpha-thalassemia. Segregation analysis was conducted on the HPFH trait FC, defined to be the percentage of Hb F-containing cells (F-cells), using the class D regressive model. Our results provide evidence for the presence of a major gene, dominant or codominant, which controls the FC values with residual familial correlations. The major gene was detected when the effects of genetic modifiers, notably beta-thalassemia and the XmnI-G gamma polymorphism, are accounted for in the analysis. Linkage with the beta-globin gene cluster is excluded. The transmission of the FC values in this pedigree is informative enough to allow detection of linkage with an appropriate marker(s). The analytical approach outlined in this study, using simple regression to allow for genetic modifiers and thus allowing the mode of inheritance of a trait to be dissected out, may be useful as a model for segregation and linkage analyses of other complex phenotypes.

Adolescent↗
PubMed1993

[Purulent meningitis among adults in the county of Frederiksborg. Therapeutic results in the period 1 January 1980--31 December 1990].

A review of 158 cases of bacterial meningitis and meningococcal sepsis in adults is presented. The patients were admitted during a 11-year period, from 1980-1990. The incidence was 5.5/100,000 adults per year, which is high. The area had epidemics of meningococcal disease in the years 1987 and 1989. The bacterial agent was meningococci in 40.5%, pneumococci in 21.5% and unknown in 27.2%. The overall lethality was 13.9%, highest (26%) in patients who were infected by pneumococci. The meningococcal relative lethality was 14%. In the period of high meningococcal incidence 1986-1989, we found a relative lethality of 17%. The overall local hospital lethality was 18.3%, which has to be compared with 11.2% among patients primarily admitted to the County hospital. The lethality among patients who underwent emergency transfer from one of the local hospitals to the County hospital was 20%, which is as high as in the group of patients treated locally. Neither of these trends lethality are statistically significant at the level of 5%, tested by chi square tests.

Adolescent↗
PubMed1993

Contributions to the phylogeny of Platyhelminthes based on partial sequencing of 18S ribosomal DNA.

Partial sequencing of the 18S ribosomal DNA gene of one nemertean and 13 free-living and parasitic Platyhelminthes (556 nucleotides), and of one nemertean and 20 Platyhelminthes (556 nucleotides) was used to test several hypotheses concerning the phylogenetic relationships of Platyhelminthes. The following conclusions were reached: the Neodermata is monophyletic; Trematoda (Aspidogastrea and Digenea) is monophyletic, although a sister group relationship of the Aspidogastrea and all other Neodermata cannot be definitely ruled out; the Cestoda comprising the Eucestoda, Amphilinidea and Gyrocotylidea is monophyletic; it is unresolved whether the Monogenea is paraphyletic; neither Gyrocotylidea and Monopisthocotylea nor Gyrocotylidea and Monogenea as a whole are sister groups; Anoplodiscus is a monopisthocotylean monogenean; none of Proseriata, Pterastericolidae/Umagillidae, Kalyptorhynchia, Rhabdocoela as a whole, Dalyelliida or the Temnocephalidae is the sister group of the Neodermata; there is some evidence that a larger taxon consisting of Proseriata, Tricladida and Rhabdocoela may be the sister group of the Neodermata but definitive evidence for a sister group relationship between the Neodermata and any turbellarian taxon is lacking; Rhabdocoela and Lecithoepitheliata are not closely related; it is unresolved whether the Rhabdocoela is monophyletic; Umagillidae, Pterastericolidae and Temnocephalidae belong to one monophylum; the Temnocephalidae are very close to the dalyelliids; Tricladida and Rhabdocoela are sister groups, the exact position of the Catenulida and Nemertini in relation to the Platyhelminthes has not been resolved, although Catenulida and Lecithoepitheliata may belong to one clade.

Animals↗
PubMed1993

Spermatogenesis in Udonella (Platyhelminthes, Udonellidea) and the phylogenetic position of the genus.

Spermatids are joined (cytophores). Two centrioles lateral and/or proximal to the nucleus form axonemes, arranged parallel with each other, that extend into a short distal cytoplasmic process. The nucleus elongates, and mitochondria fuse to form a single elongate mitochondrion. The part of the spermatid containing the axonemes, nucleus and mitochondrion elongates to a thread-like spermatozoon, surrounded at its base (at the level near the basal bodies) by an arching membrane where the sperm detaches from the residual cytoplasm. At no stage are there free flagella (except for short free flagellar tips), an intercentriolar body or a median cytoplasmic process. A few peripheral microtubules and a compact dense body, not membrane bound and closely associated with the mitochondrion, were seen in spermatids. Spermiogenesis in Udonella is interpreted as derived from proximo-distal fusion by a shifting of the basal bodies deeper into the cytoplasm and a consequent loss of the median cytoplasmic process. Both the ultrastructure of the protonephridia and spermiogenesis indicate that Udonella does not represent the sister group of all other neodermatans, but is a secondarily modified "advanced" neodermatan. Lack of convincing synapomorphies indicates that the taxon Cercomeridea as a defined by Brooks (1989a, b) is invalid.

Animals↗
PubMed1993

A fast, sensitive pattern-matching approach for protein sequences.

Pattern-matching algorithms are a powerful tool for finding similarities and relationships among the steadily growing amount of known protein sequences. We present a fast, sensitive pattern-matching algorithm that describes a pattern by its physico-chemical properties rather than by occurrence of amino acids, using a fast, dynamic programming algorithm. Selected examples will demonstrate applications and advantages of our approach.

Algorithms↗
PubMed1993

Linkage analysis in German breast cancer families with early onset of the disease, using highly polymorphic markers from the chromosome 17q11-q24 region.

Linkage analysis in German breast cancer families with early onset of the disease by using six markers on chromosome 17q11-q24 has been carried out. In the region between markers D17S250 and GH, three markers showed positive LOD scores at an estimated distance of zero. Evidence for linkage is greatest for D17S250, with a LOD score of 2.42.

Adult↗
PubMed1992

Ultrastructure of sperm and spermatogenesis of Rugogaster hydrolagi, Schell 1973 (Platyhelminthes, Trematoda, Aspidogastrea, Rugogastridae).

Mature sperm of Rugogaster hydrolagi exhibit the structure typical of Trematoda, with 2 axonemes of the 9+ "1" pattern being incorporated into the sperm body, dorsal and ventral microtubules occurring in the principal region that contains the nucleus and mitochondrion, and a complete row of peripheral microtubules lying in the proximal region surrounding the two axonemes. During spermiogenesis, a zone of differentiation develops that comprises a row of microtubules along the cell membrane and an adjacent dense region along the nuclear membrane. The intercentriolar body and centrioles appear between the microtubules and the nucleus. Free flagella with striated rootlets grow out in opposite directions, the cell membrane protrudes and lengthens into a median cytoplasmic process (MCP), the nucleus and mitochondrion move into the MCP and the flagella rotate and eventually fuse with the process. A dense region develops in the spermatid shaft some distance from the proximal end, but it is not present in the mature sperm. The spermatid elongates and is eventually pinched off from the residual body at the level of the arching membranes after the rootlets and intercentriolar body have disappeared. Thus, spermatogenesis and sperm in the aspidogastrean Rugogaster hydrolagi correspond to those in digenean Trematoda.

Animals↗
PubMed1992

Ultrastructure of the developing protonephridial system of the cercaria of Philophthalmus sp. (Trematoda, Digenea).

The fully developed flame bulb of Philopthalmus exhibits the structure characteristic of Trematoda and Monogenea: external and internal ribs forming a weir, external and internal leptotriches, and two longitudinal cytoplasmic cords connected by a septate junction. The proximal canal has a septate junction and surface lamellae. In developing cercariae, perikarya of terminal and proximal canal cells are close together, and sheet-like outgrowths of the terminal cell are externally surrounded by cytoplasm of the proximal canal cell containing a septate junction. Internal outgrowths and external cytoplasm are connected by many "membranes", i.e. desmosome-like structures. Internal sheets break up into internal ribs, and the external cytoplasm breaks up into external ribs, external and internal ribs connected by the filtration "membrane". The developing distal excretory duct possesses a septate junction and many branching and looping lamellae. A comparison of Philopthalmus with the cestode Austramphilina elongata, the only other platyhelminth species in which the development of the protonephridia has been studied at the ultra-structural level, revealed that the two species differ in the presence and absence, respectively, of a septate junction in the flame bulb at an early stage of development.

Animals↗
PubMed1992

Ultrastructure of the protonephridial system, of Anoplodiscus cirrusspiralis (Monogenea Monopisthocotylea).

The flame bulb is formed by a terminal cell and a proximal canal cell. The weir consists of interdigitating ribs all of which form one circle, i.e. alternating ribs do not have distinctly 'internal' or 'external' positions. Cytoplasmic cords are absent and all ribs, i.e. those continuous with the proximal canal cell and those continuous with the terminal cell, form external leptotriches. At least some external leptotriches have interconnected branches extending along the flame bulb. Internal leptotriches are not branched and arise from the basal perikaryon of the terminal cell. In the cytoplasmic cylinder at the tip of the flame bulb, structures resembling incomplete septate junctions were seen. However, neither the cytoplasmic cylinder nor the small protonephridial capillaries contain complete septate junctions as found in all other Monogenea Polyopisthocotylea, Monogenea Monopisthocotylea, Trematoda Aspidogastrea and Trematoda Digenea examined to date. In the lack of a septate junction, Anoplodiscus resembles Udonella, Amphilinidea, Gyrocotylidea and Eucestoda. However, the presence in this species of rudimentary septate junctions in the small capillaries and of complete junctions in larger ones indicates that complete junctions have been secondarily lost. Anoplodiscus resembles the Monogenea and Trematoda in the presence of lamellae in the larger protonephridial ducts. For the first time in a monogenean, the ultrastructure of the excretory bladder is described. A nucleated convoluted duct opens through a narrow connecting duct into the bladder, which in turn opens through a narrow connecting duct into the excretory pore lined by tegument. Convoluted duct, connecting ducts and bladder are lined by a lamellated epitheliu.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Evaluation of Leptospirillum ferrooxidans for Leaching.

The importance of Leptospirillum ferrooxidans for leach processes has been evaluated by studying the lithotrophic flora of three mine biotopes and a heap leaching operation, by percolation experiments with inoculated, sterilized ore, and by morphological, physiological, and genetic investigations of pure and mixed cultures of L. ferrooxidans, Thiobacillus ferrooxidans, and Thiobacillus thiooxidans. In biotopes of 20 degrees C or above, Leptospirillum-like bacteria are as abundant as T. ferrooxidans. Leptospirilli represent at least one-half of the ferrous-iron-oxidizing population. Percolation experiments confirmed this result. Leptospirilli were as numerous as T. ferrooxidans. At reduced temperatures, the generation times of leptospirilli increase more so than those of T. ferrooxidans. At 14 degrees C, Leptospirillum grows slowly and T. ferrooxidans dominates the population. Physiological investigations indicate that L. ferrooxidans is a strict chemolithoautotroph, metabolizing only ferrous iron and pyrite. Even an addition of 0.05% (wt/vol) yeast extract inhibited its growth. The maximum ferrous-iron-oxidizing activity of L. ferrooxidans amounts to about 40% of the activity of T. ferrooxidans. After growth on sulfidic ore, both species exhibit reduced iron-oxidizing activities, L. ferrooxidans exhibiting one-third and T. ferrooxidans exhibiting one-seventh of their maximum activities. Surprisingly, the absolute values are similar. For indirect leaching, L. ferrooxidans is as important as T. ferrooxidans. This was confirmed by the results of percolation experiments. L. ferrooxidans together with T. thiooxidans mobilized metals at least as well as T. ferrooxidans did. The best results were obtained with a mixed culture of all three species.

Journal Article↗
PubMed1991

[Amebic abscess in the liver diagnosed initially as pneumonia].

Three cases of amoebic liver abscess were initially diagnosed as pneumonia. All three patients had fever, respiratory pain at the right costal margin, increased erythrocyte sedimentation rate and white blood cell count, pulmonary infiltrate and pleural exudate. The first case was a relapse of an infection acquired at a visit to the tropics sixteen years previously. The second patient had spent a short holiday in Morocco seven months before the illness and the third patient was probably infected in Greenland. The correct diagnosis was confirmed by demonstration of a cavity in the liver, amoebic antibodies in the blood and good response to amoebicidal treatment which was combined with closed drainage in two cases.

Adult↗
PubMed1991

Ultrastructure of sperm and spermatogenesis of Lobatostoma manteri (Trematoda, Aspidogastrea).

Mature sperm has two axonemes of the 9 + '1' pattern incorporated in the sperm body, a row of peripheral microtubules interrupted along part of the sperm by the axonemes, some microtubules in the interior of the sperm and a long lateral extension (lobe) of the sperm body, an elongate nucleus and mitochondrion, and many dense rod-like structures. A supporting rod extends underneath a specialized region consisting of alternating thin and thick transverse rows of irregular dense patches, and with surface ridges around (all or) most of the surface of the sperm. Primary spermatocytes in the prophase of the first meiotic division have synaptonemal complex(es), and are rich in mitochondria. In early spermiogenesis, mitochondria are arranged around the surface of the nucleus, a dense layer appears at one pole of the nucleus, close to an apposed dense layer at the cell membrane in which a row of microtubules develops. The intercentriolar (= central) body develops close to the nucleus. The fully developed intercentriolar body has a regular striation and is located perpendicular and close to the surface of the nucleus. Two flagella extend into the space surrounding the outgoing median process, their basal bodies are located perpendicular to the intercentriolar body and their cross-striated rootlets extend along the surface of the rounded nucleus. At a later stage, rootlets and flagella become more parallel with the intercentriolar body, the nucleus and the fused mitochondria migrate into the median process, and the flagella become incorporated into the median process (= sperm body). The outgrowing spermatozoa are connected to the cytoplasm of the cytophore by dense arching membranes. Finally, rootlets of flagella are resorbed and the spermatozoa are pinched off close to the basal bodies. Two species (Lobatostoma and Multicotyle) of the same family differ strongly in the type of spermiogenesis, although their mature sperm is of the same basic type, i.e. spermiogenesis is not necessarily more useful for phylogenetic considerations than sperm structure.

Animals↗
PubMed1991

Size differences in hamuli of Kuhnia scombri (Monogenea: Polyopisthocotylea) from different geographical areas not due to differences in host size.

Hamuli of Kuhnia scombri from Scomber australasicus and S. japonicus from several localities in the Pacific Ocean show marked differences in length. Hamuli from large fish are slightly longer than those from small fish caught in the same geographical area (northern New Zealand). Differences correlated with host size are much less than those associated with geographical area and may be due to infections acquired in different localities. Taxonomic studies of Monogenea must take geographical variation and, to a lesser degree and in at least some species, effects of host size into consideration.

Animals↗
PubMed1990

[Metastatic spinal compression syndrome. Symptoms, diagnosis, treatment and prognosis].

A retrospective study of 398 patients suffering from metastatic compression of the spinal cord or cauda equina is presented. The study comprised almost all relevant medical records of patients admitted to hospital in the eastern part of Denmark in the period 1979 through 1985. Carcinoma of the lung, prostate, breast and kidney were the most frequent primary malignancies causing spinal compression. Most patients were treated with laminectomy, or radiotherapy or with laminectomy and radiotherapy combined. The effect of the treatment was estimated by evaluation of motor function and sphincter control. Treatment with laminectomy followed by radiotherapy was significantly superior to treatment with laminectomy or radiotherapy alone. But if the patients' motor function and primary tumour were taken into account, no significant difference between the treatments was observed. The efficacy of treatment depended upon the symptoms when the diagnosis was established, and accordingly early diagnosis is of the utmost importance. The incidence of metastatic compression increased during the period covered by the study, and since this condition must not go untreated, awareness of the symptoms, primarily pain, is essential.

Adolescent↗
PubMed1990

Sequence similarities between tryptophan synthase beta subunit and other pyridoxal-phosphate-dependent enzymes.

On the basis of 8 tryptophan synthase beta subunits (EC 4.2.1.20) consensus patterns were constructed comprising two conserved motifs. Screening of the SWISSPROT protein sequence database with these patterns indicates similarities with O-acetylserine sulfhydrolases (EC 4.2.99.8), threonine synthases (EC 4.2.99.2), L- and D-serine dehydratases (EC 4.2.1.13/EC 4.2.1.14) and threonine dehydratases (EC 4.2.1.16). Using multiple alignment procedures the similar regions could be extended. In connection with their pyridoxal-phosphate-binding-capacity and their positions in biochemical pathways evolutionary relationships among these enzymes are discussed.

Amino Acid Sequence↗
PubMed1990

Metastatic epidural spinal cord compression. Results of treatment and survival.

All medical records of patients treated for metastatic compression of the spinal cord or cauda equina in the eastern part of Denmark from 1979 through 1985 were reviewed. With regard to treatment response and survival, 345 patients could be evaluated. Carcinoma of the lung (19%), prostate (18%), breast (13%), and kidney (10%) were the most frequent primary malignancies causing spinal compression. The outcome of treatment depended primarily on the patients' condition at the time of diagnosis: 79% of the patients who were able to walk before the treatment remained ambulatory, whereas only 21% of the nonambulatory paraplegic patients and 6% of the paralytic patients regained walking ability. Patients treated with laminectomy followed by radiotherapy seemed to respond better than patients treated with radiotherapy or laminectomy alone, but when the patients' pretreatment motor function was taken into account no significant difference was found between the three forms of treatment. In the subgroup of nonambulatory patients, however, a significantly better restoration of gait was observed in patients treated with the combination of laminectomy and radiotherapy than in patients treated with radiotherapy alone. A longer survival in the group treated with the combination of laminectomy and radiotherapy may reflect that these patients were in a lower stage of disease and thus had a better potential of regaining motor function. The results call for prospective randomized studies.

Adolescent↗