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Biomedical subjects

S Kubik

Publications and source records attributed to S Kubik.

At least 19 recordsLinked to original sources
PubMed2000

Understanding hippocampal activity by using purposeful behavior: place navigation induces place cell discharge in both task-relevant and task-irrelevant spatial reference frames.

Continuous rotation of an arena in a cue-rich room dissociates the stationary room-bound information from the rotating arena-bound information. This disrupted spatial discharge in the majority of place cells from rats trained to collect randomly scattered food. In contrast, most place cell firing patterns recorded from rats trained to solve a navigation task on the rotating arena were preserved during the rotation. Spatial discharge was preserved in both the task-relevant stationary and the task-irrelevant rotating reference frames, but firing was more organized in the task-relevant frame. It is concluded that, (i) the effects of environmental manipulations can be understood with confidence only when the rat's purposeful behavior is used to formulate interpretations of the data, and (ii) hippocampal place cell activity is organized in multiple overlapping spatial reference frames.

Animals↗
PubMed1996

Brain cooling in humans--anatomical considerations.

Vascular arrangements allowing a bulky transfer of venous blood from the skin of the head and from nasal and paranasal mucous membranes to the dura matter provide an excellent anatomical basis for the convection process of cooling, caused by evaporation of sweat or mucus. The dura mater, with its extraordinarily high vascularization controlled by a potent vasomotor apparatus, may transmit temperature changes to the cerebrospinal fluid (CSF) compartment. Temperature gradients of the CSF may in turn influence the temperature of brain parenchyma (1) directly, along the extensive contact area between the cerebrocortical surface and the CSF-compartment, or (2) indirectly, via brain arteries that extend over long distances and arborize within the subarachnoid space before entering the pial vascular network and brain parenchyma. Numerous subarachnoid and pial arterial branches exposed to the CSF have diameters in the range of the vessels of the retia mirabilia of animals in which selective brain cooling has been clearly established experimentally. It is also shown that the arrangements of venous plexuses within the vertebral canal provide anatomical preconditions for a cooling of the spinal cord via the CSF. The possibility of spinal cord and spinal ganglia cooling by temperature convection via venous blood--cooled in the venous networks of the skin of the back--flowing through numerous anastomoses to the external and internal vertebral plexuses and, finally, into the vascular bed of the spinal dura is discussed on the basis of anatomical facts.

Arachnoid↗
PubMed1995

Synthesis and coupling reactions of alpha,alpha-dialkylated amino acids with nucleobase side chains.

Several di- and tripeptides containing protected purine (adenine) and pyrimidine (thymine) residues on their side chains were synthesized. The parent amino acids alpha, alpha-dialkylated in a symmetrical manner. An effective coupling procedure was developed for these sterically hindered amino acids: the fluoren-9-ylmethyloxycarbonyl-protected amino acid was dehydrated to its oxazolinone form, which was coupled in good yields with amino esters in hot tetrachloroethane.

Adenine↗
PubMed1995

[Topography of the hypophysis and its neighboring structures].

The first part of the article informs about four points: the skeletal structures of the middle cranial fossa, the basic divisions of the gland and their connections with the hypothalamus, its blood supply, and its development. The topographic part deals with the incorporation of the pituitary gland in the sella turcica, its relationship to the meninges, the subarachnoid cavity and other neighbouring structures, especially the sphenoidal sinus, the posterior ethmoidal cells as well as the chiasma opticum. With respect to the latter, the position of the fibres in the optic nerve, chiasma and optic tract and the consequences of lesions in characteristic areas are described. Finally, the variant structures of the cavernous sinus and the topography of its contents are discussed. Detailed data can be found about the course of the oculomotor nerves and the possible locations of their lesions.

Cavernous Sinus↗
PubMed1995

Topographic relationship of the ventromedial lymphatic bundle and the superficial inguinal nodes to the subcutaneous veins.

The relationships between lymph vessels and veins are of clinical importance for the prevention of injury to collectors and resulting edema after removal of veins. Injection preparations of the lymph vessels and veins showed that on the dorsum of the foot the collectors overcross the veins; however, in all remaining areas they undercross them. Only the great saphenous vein is overcrossed by lymph collectors. It also has accompanying lymph vessels but its vascular sheath, however, does not contain any lymph vessels. The position of the collectors depends on the thickness of the subcutaneous adipose tissue. On the dorsum of the foot the lymphatics are often closely bound up with the corium; on the lower leg, however, they are embedded in the adipose tissue. Some collectors are closely related to perforator veins. In the knee region the lymph bundle ascends dorsomedially to the medial condylus of the femur. On the thigh, where the subcutaneous fatty tissue is thick, the collectors from three layers. The superficial inguinal lymph nodes draining the leg and the external genitalia are situated around the saphenous opening and are closely related to the subinguinal venous star, so that in surgical intervention the collectors of this region are more exposed to danger than in other regions.

Aged↗
PubMed1995

Anatomic relationships along the low-middle convexity: Part I--Normal specimens and magnetic resonance imaging.

Sagittal sections of anatomic specimens and magnetic resonance images well display the individual gyri and sulci along the low-middle convexity. Those familiar with the typical pattern and with the common normal variations will be able to use sagittal magnetic resonance imaging to correctly localize lesions by identifying: (a) the five major rami of the sylvian fissure; (b) the subdivision of the triangular inferior frontal gyrus into the M-shaped partes orbitalis, triangularis, and opercularis by the anterior horizontal and anterior ascending rami of the sylvian fissure; (c) the zig-zag shape of the middle frontal gyrus, which characteristically angles sharply and inferiorly to fuse with the anterior surface of the precentral gyrus; (d) T-shaped bifurcation of the posterior end of the inferior frontal sulcus to form the inferior precentral sulcus; (e) separation of the central sulcus from the sylvian fissure by union of the opercular ends of the precentral and postcentral gyri to form the subcentral gyrus inferior to the central sulcus; (f) narrower sagittal dimension of the postcentral gyrus than the precentral gyrus; (g) horseshoe shape of the supramarginal gyrus perched atop the posterior ascending ramus of the sylvian fissure; (h) similar horseshoe shape of the angular gyrus perched atop the posterior end of the superior temporal sulcus; (i) commonly intercalated accessory presupramarginal and preangular gyri; and (j) the arcuate course of the intraparietal sulcus, which separates the superior from the inferior parietal lobules. The anatomic relationships described are more nearly constant anteriorly than posteriorly. When used as described, they prove helpful in correctly localizing pathology and in planning a surgical approach to lesions that may be difficult to localize on the basis of axial or coronal plane magnetic resonance images.

Brain↗
PubMed1992

Analgesic use in home hospice cancer patients.

BACKGROUND: Pain control in hospice patients in the home may be compromised by concerns about overuse of analgesics, particularly narcotics. METHODS: A retrospective chart audit of analgesic type and amount was performed on the medical records of 100 cancer patients receiving hospice care in the home. Different types and amounts of analgesics were converted to a common standard, an oral morphine equivalent (OME) relative to 1 mg of oral morphine sulfate. Descriptive statistics were used to characterize patient analgesic use during the entire course of hospice care and the last 5 days of life. Associations between analgesic use and select patient characteristics (age, sex, cancer site, metastases, and pain intensity at admission) were explored. RESULTS: Ninety-one percent of the sample had used analgesics at some time during hospice care. The proportion of patients using analgesics increased as death approached. The mean and median daily analgesic use over the entire period were 114 and 82 OMEs and during the last 5 days 140 and 84 OMEs, respectively. The range of mean daily analgesic use was between 10 and 735 OMEs. CONCLUSIONS: Individual variability in analgesic use was demonstrated. Not all patients required analgesics, and among those who did there was remarkable variation in the amount used. Large and even enormous doses of analgesics may sometimes be required to control cancer pain.

Aged↗
PubMed1988

Unanswered questions concerning the indication for cochlear implant.

In a discussion of the function of cochlear implant (CI), the following criteria should be mentioned: (1) If possible, all deaf persons (including the prelingually deaf and children) should benefit from CI. (2) Since the number of patients with late deafness is doubtlessly decreasing with better prevention and medical care (elimination of ototoxic damage, decrease of iatrogenic deafness), the percentage distribution of the deaf will be displaced in favor of the prelingually deaf. At present, the ratio of cases of late deafness to those of prelingual deafness among our CI candidates is 1:3. (3) The objective of CI must be to provide the advantage of the procedure to children as early as possible. This means that under certain circumstances a technique that is as low in risks as possible and with a handy implement should already have been used in patients at the age of 3 to 4 years.

Adaptation, Psychological↗
PubMed1986

Anatomy of the veins of the dorsum pedis with regard to their suitability as vascular grafts in reconstructive microsurgery.

Attempts to locate veins suitable as micro-surgical vascular grafts were carried out in 16 preparations of the subcutaneous venous network of the dorsum pedis. For this reason the length, diameter, valve distances and frequency of longitudinal veins were especially examined. Four types of veins were defined as being suitable for transplantation and it was established that they are situated in the medial half of the dorsum pedis in the so-called microsurgical area in all cases. Collecting and conducting veins can be distinguished by means of the location of the valves, which are generally bicuspidal. In most cases, the level of the opening spaces of both the segment and the opening valves lies parallel to the surface of the skin.

Humans↗
PubMed1986

Extracochlear sixteen-channel electrode system.

This article summarizes 10 years of work by the Cologne-Düren Research Group. The purpose of our research was to develop a noninvasive operation technique and to avoid opening the inner ear cavities (extracochlear technique). On the basis of empiric experience, a 16-channel electrode system was developed. The electrodes were fixed on a "hedgehog" contact plate with an arrangement corresponding to the projection of the cochlea. A microprocessor, which enables individual programmability in the different groups of deaf persons (prelingual, postlingual deafness), was integrated into the speech processor. Experience to date was summarized in statistical data. Not only the results of the psychoacoustic tests, but also the applicability of the cochlear implant as seen by the patients were considered. We next plan to miniaturize the system.

Adolescent↗
PubMed1985

Extracochlear eight-channel electrode system.

The Cologne-Düren research group has developed a new extracochlear eight-channel electrode system. The first observations on six cases have shown encouraging psychoacoustic results.

Acoustic Impedance Tests↗
PubMed1985

CLS 2210, hyaluronidase and the cardiac lymphatic system.

Earlier studies have shown that hyaluronidase exerts a potent influence upon the lymphatic system of the myocardium and that it reduces the size of myocardial infarcts after coronary occlusion. In this study we compared, in mongrel dogs, the effect of intravenous hyaluronidase or CLS 2210 upon the cardiac lymphatic vessels. We observed that in CLS 2210-treated animals the number of visualized cardiac lymphatic vessels was significantly higher than in the hyaluronidase-treated control group. We have previously demonstrated a cardioprotective effect of hyaluronidase in the treatment of acute myocardial infarction. The present experimental data indicate that intravenous CLS 2210 may have a definite role in the management of acute coronary occlusion. Further studies are needed to confirm these preliminary findings.

Animals↗
PubMed1984

Our extra-scalar operating method of cochlear implantation. Experience with 46 cases.

We attempted to elaborate an operating method, whereby the electrodes could be placed without opening the scale tympani or vestibule. In this respect the medial wall of the tympanic cavity, i.e. the bony cochlear wall provides the most favourable means of access. It is easy to reach surgically and provides adequate access to the cochlea.

Cochlea↗