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Biomedical subjects

K Rohde

Publications and source records attributed to K Rohde.

At least 19 recordsLinked to original sources
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↗
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↗
PubMed1990

Metastatic spinal cord compression. Occurrence, symptoms, clinical presentations and prognosis in 398 patients with spinal cord compression.

We reviewed all medical records concerning patients suffering from spinal cord or cauda equina compression (SCC) secondary to cancer, in the eastern part of Denmark, from 1979 through 1985. During the period the incidence of SCC in cancer patients went up from 4.4% to 6%. However, this increase was not significant. The series comprised 398 cases, with carcinoma of the prostate (19%), lung (18%), breast (14%) and kidney (10%) accounting for 61%. The symptoms were evaluated in accordance with the patients rating of pain, motor deficits, sphincter control and paraesthesia, whereas the clinical manifestations were classified on the basis of motor deficit and bladder dysfunction. During the period preceding the diagnosis of SCC, 83% of the patients suffered from back pain, 67% from deteriorating gait and 48% had retention of the urine. In 35% of the patients there was no sphincter disturbance and 10% had normal sensory function. The outcome of treatment was estimated by changes in motor deficits and sphincter function, and depended primarily on the patients condition at the time of the diagnosis. Of the patients who were able to walk before treatment, 79% remained ambulatory, whereas only 18% of the non-ambulatory patients regained walking ability. Patients treated by decompressive laminectomy followed by radiotherapy apparently had a better response than patients treated with surgery or irradiation alone, but when the patients pre-treatment motor function was taken into account, no significant difference was observed. The study may call for a properly randomized trial with careful stratification of tumour biology, performance status and neurological deficits.

Adolescent↗
PubMed1990

Marine parasites: an Australian perspective.

A review is given of major studies in marine parasitology in Australia. Aspects discussed include: geographical distribution of parasites in Australian coastal waters and their affinities to parasites of other zoogeographical regions; species diversity in Australian coastal surface and deep waters; use of marine parasites for stock discrimination; use of marine parasites as ecological models; ultrastructural and phylogenetic studies of marine parasites; and effects of marine parasites on their hosts.

Animals↗
PubMed1990

A novel pathway for secretory proteins?

In eukaryotes, most proteins which are transported to the extracellular space, into mitochondria or into chloroplasts are synthesized as precursor polypeptides containing cleavable N-terminal signal or targeting sequences. We have searched the literature for proteins that are exported from the cytosol without being proteolytically processed. Some of these proteins contain uncleaved signal or targeting sequences. However, among secretory proteins there is a class that does not possess hydrophobic signal sequences and appears to leave the cell by a secretory pathway clearly distinct from the classical route through the endoplasmic reticulum and Golgi apparatus.

Acylation↗
PubMed1989

EMBOPRO--an automatically generated protein sequence database.

For the identification of newly sequenced proteins it is necessary to have a large stock of known proteins for comparison. In this paper we present an automatically generated protein sequence database. The translation program introduced allows a periodical translation of every new release of the EMBL database. Possible errors of the translation are discussed as well as the reliability of the nucleotide sequence data, which turns out to be quite good. A comparison of our translated database with some established ones is given.

Amino Acid Sequence↗
PubMed1988

Sense receptors with electron-dense supporting structures, and centrioles in the nerve fibres of Gieysztoria and Rhinolasius (Platyhelminthes, Rhabdocoela).

The ultrastructure of two types of sense receptors each is described for Gieysztoria and Rhinolasius. In Gieysztoria, one receptor possesses a number of long microvilli, a cilium with a cross-striated rootlet, a septate desmosome, and an electron-dense band apical to the desmosome. The band forms a complex reticulate extension into the base of the receptor. The second receptor is without microvilli, has a cilium with a long cross-striated rootlet, and a septate desmosome with a short basal electron-dense extension or extensions which do not form a complete ring. In Rhinolasius, one receptor possesses a short bulbous cilium without a rootlet, with a septate desmosome of the pleated sheet (comb) type and a weakly developed electron-dense band beneath it. The second receptor has a long cilium with cross-striated rootlet, and a septate desmosome with a weakly developed electron-dense band apical to it. Centrioles were found in nerve fibres of both species.

Animals↗
PubMed1988

Ultrastructure of the protonephridia of Monocelis (Proseriata, Monocelididae).

The ultrastructure of the protonephridia of Monocelis sp. (Platyhelminthes, Proseriata) is described. The terminal part of the protonephridia ('terminal complex') consists of a terminal cell, a proximal canal cell and at least one supporting cell. The nucleus of the terminal cell is close to the rootlets of the cilia which form the flame. The weir consists of longitudinal external (small) and internal (large) ribs containing cross-striated microfilaments and connected by a membrane. External ribs arise from cytoplasm of the terminal cell, internal ribs from the proximal canal cell, although continuity of an internal rib and a terminal cell was observed in one case. The terminal cell also gives rise to internal leptotriches. Two thick cytoplasmic cords connected by a desmosome extend along much of the flame. A maximum of two supporting cells with nuclei close to the weir were found along the weir, separated from it by cell membranes. Cells with nuclei some distance from the weir may be in contact with the weir as well. The internal surface area of protonephridial capillaries is enlarged by lamellae and reticula. The wall of some but not all capillaries possesses one or several desmosomes. There are many lateral flames. Differences between the protonephridia of Monocelis and other 'turbellarians' and the Neodermata are discussed.

Animals↗