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Biomedical subjects

A Karl

Publications and source records attributed to A Karl.

17 recordsLinked to original sources
PubMed2006

Lymphoscintigraphy in penile cancer: limited value of sentinel node biopsy in patients with clinically suspicious lymph nodes.

The staging lymph node dissection in patients with penile carcinoma is accompanied with a high morbidity. As many patients are free of nodal metastases the lymphoscintigraphic sentinel node biopsy is supposed to minimize perioperative morbidity in these patients. In the current study the accuracy of the lymphoscintigraphic sentinel node biopsy was verified against the gold standard of radical inguinal dissection. In particular, patients with enlarged lymph nodes have also been included since one half of these patients is known to have histologically negative lymph nodes. Between 2000 and 2004 fifteen patients with penile carcinoma were elected to undergo bilateral groin dissection, thus 30 inguinal areas have been dissected. Nine patients have had clinically palpable nodes. All patients underwent lymphoscintigraphy after injection of Tc99-nanocolloid subcutaneously into the peritumoral area. Intraoperatively the sentinel nodes were identified with the aid of a gamma ray detection probe and excised. Afterwards a standard groin dissection was performed and the different lymph nodes were histopathologically assessed separately. In all patients lymph nodes with high radioactivity uptake were detected bilaterally. In 10 out of 30 inguinal areas histopathologically positive lymph nodes were present. In four of them the sentinel node was positive for tumor but in six dissection areas lymph node metastases were found despite a negative sentinel node. These patients had clinically palpable lymph nodes in their histologically positive inguinal regions. If no palpable nodes were present dynamic sentinel biopsy detected the positive nodes. The current study showed that dynamic sentinel node biopsy in patients with clinically suspicious lymph nodes is of low value for detection of lymphatic spread in penile cancer. Therefore the gold standard in these patients remains the radical groin dissection. However, dynamic sentinel node biospy is still a promising strategy to identify lymphatic spreading in clinically N0 patients and therefore to prevent unnecessary groin dissection.

Adult↗
PubMed2006

Role of endocrine and inflammatory alterations in comorbid somatic diseases of post-traumatic stress disorder.

Since its first description in the Diagnostic and Statistical Manual for Mental Disorders, post-traumatic stress disorder (PTSD) has been characterized as a disorder of altered affective functioning which causes tremendous distress. In addition, it has been recognized that PTSD is not only accompanied by ''poor health'' but also by a number of specific and non-specific ''somatic'' pathologies, such as cardiovascular, autoimmune and physical complaints/chronic pain. It has been hypothesized that alterations of the hypothalamic-pituitary-adrenal (HPA) axis, the sympathetic-adrenal-medullary (SAM) and the immune system may mediate or facilitate these somatic conditions. The aims of this review are to summarize studies that report altered somatic functioning in PTSD and to review how endocrine and immune function differentially affect PTSD-related somatic malfunction. It is hypothesized that alterations of HPA axis and SAM system permit disinhibition of inflammatory mechanisms, which in turn foster the development of somatic diseases as well as self-reported physical complaints.

Adult↗
PubMed2001

Reorganization of motor and somatosensory cortex in upper extremity amputees with phantom limb pain.

Phantom limb pain (PLP) in amputees is associated with reorganizational changes in the somatosensory system. To investigate the relationship between somatosensory and motor reorganization and phantom limb pain, we used focal transcranial magnetic stimulation (TMS) of the motor cortex and neuroelectric source imaging of the somatosensory cortex (SI) in patients with and without phantom limb pain. For transcranial magnetic stimulation, recordings were made bilaterally from the biceps brachii, zygomaticus, and depressor labii inferioris muscles. Neuroelectric source imaging of the EEG was obtained after somatosensory stimulation of the skin overlying face and hand. Patients with phantom limb pain had larger motor-evoked potentials from the biceps brachii, and the map of outputs was larger for muscles on the amputated side compared with the intact side. The optimal scalp positions for stimulation of the zygomaticus and depressor labii inferioris muscles were displaced significantly more medially (toward the missing hand representation) in patients with phantom limb pain only. Neuroelectric source imaging revealed a similar medial displacement of the dipole center for face stimulation in patients with phantom limb pain. There was a high correlation between the magnitude of the shift of the cortical representation of the mouth into the hand area in motor and somatosensory cortex and phantom limb pain. These results show enhanced plasticity in both the motor and somatosensory domains in amputees with phantom limb pain.

Adult↗
PubMed2001

[The phantom and stump phenomena interview (PSPI)].

RESEARCH QUESTION: A structured German-language interview was developed for the assessment of painful and non-painful phantom and stump phenomena after amputation. The aim was a thorough assessment of the quality, quantity and time course of these phenomena, which is of scientific as well as therapeutic relevance. METHODS: Each phenomenon was assessed using visual analogue scales as well as qualitative descriptors adapted from the McGill Pain Inventory and from literature reports. The factor structure and psychometric properties of the interview were evaluated in a sample of 139 upper and lower limb amputees. Test-retest coefficients were obtained in a subset of 20 amputees. RESULTS: As expected, all pain-related scales showed a two-dimensional internal structure with the factors "affective pain" and "sensory pain". For the non-painful phantom sensations, three factors "general/kinesthetic phantom sensations", "phantom movements" and "paresthesias" were obtained, while for non-painful stump sensations only one general factor emerged. The internal consistency was high with respect to the pain-related scales and was still satisfying for the scales that cover nonpainful phantom and stump phenomena. All scales have sufficient validity. Test-retest coefficients suggest a satisfactory stability of all scales that assess present phenomena, while the stability of the retrospective scales is markedly lower and in some cases insufficient. CONCLUSIONS: The phantom and stump phenomena interview is a highly reliable and valid instrument to assess present perceptual phenomena after amputation. Only the included retrospective scales apparently show low stability scores over time. This raises the more general question of the validity of retrospective pain reports.

Adult↗
PubMed2001

The relationship of perceptual phenomena and cortical reorganization in upper extremity amputees.

In this study 16 unilateral upper extremity amputees participated in a comprehensive psychophysiological examination that included the assessment of painful and non-painful phantom and stump sensations, thermal and electric perception as well as two-point discrimination thresholds, the detailed analysis of referred sensation and the measurement of reorganizational changes in primary somatosensory cortex using neuroelectric source imaging. Reorganization of the primary somatosensory cortex was associated with increased habitual phantom limb pain, telescoping, non-painful stump sensations and painful referred sensation induced by painful stimulation. It was unrelated to non-painful phantom sensations, non-painful referred sensation elicited by painful or non-painful stimulation, painful referred sensation elicited by non-painful stimulation, perception thresholds and stump pain. These data substantiate the hypothesis that painful and non-painful phantom phenomena are mediated by different neural substrates.

Adaptation, Physiological↗
PubMed2001

Psychophysiological reactivity of aggressive drivers: an exploratory study.

In the United States, motor vehicle accidents are the leading cause of accidental death and injury. Aggressive driving, which has been identified as a major risk factor for motor vehicle accidents by transportation authorities, is thus an important topic of study. This study compared the physiological reactivity of self-referred aggressive and nonaggressive drivers. Heart rate, blood pressure, facial muscle activity, and skin resistance were monitored as participants listened to idiosyncratic vignettes of driving and fear-provoking scenarios, as well as during a standard stressor task (mental arithmetic). The results were that aggressive drivers exhibited significant increases in muscle tension and blood pressure during the driving vignettes, relative to controls. They also responded to the fear vignette and mental arithmetic in a qualitatively different fashion from that of controls. The aggressive drivers responded to these stimuli with less overall heart rate and electrodermal reactivity, but increased blood pressure and muscle tension. In contrast, the controls responded to the fear vignette and mental arithmetic primarily with increased heart rates and decreased skin resistance. The findings suggest that both physiological hyperarousal as well as differential responses to stressful stimuli may contribute to aggressive driving. Implications for interventions with this population are discussed.

Accidents, Traffic↗
PubMed2000

A neural substrate for nonpainful phantom limb phenomena.

Activity in the cerebral cortex associated with non-painful phantom limb sensation was studied in 14 upper extremity amputees. In four subjects, repetitive tactile stimulation of the digits or the lower corner of the mouth elicited non-painful phantom sensation in the amputated limb, in the remaining 10 patients no sensation could be evoked. Neuroelectric source imaging revealed significantly elevated activity in SI and posterior parietal cortex, and significantly decreased activity in ipsilateral SII cortex when referred sensations were present. However, nonpainful referred phantom sensations were not associated with a shift of the cortical representation of the mouth into the hand region, as previously suggested. Nonpainful phantom limb experiences seem to have widely distributed neural networks in multiple cortical regions.

Adult↗
PubMed1997

Interaction of GLP-I and leptin at rat pancreatic B-cells: effects on insulin secretion and signal transduction.

The incretin effect is reduced in NIDDM, although a corresponding attenuation of incretin hormone secretion does not occur. We characterized the direct interaction of GLP-I, an important incretin hormone, and leptin on insulin secretion and signal transduction in B-cells. Leptin inhibited GLP-I stimulated insulin release from the isolated perfused rat pancreas. Both phases of the biphasic insulin secretory response were inhibited. GLP-I receptor binding and GLP-I induced cAMP generation remained unchanged. Leptin reduced the GLP-I mediated increase of cytosolic Ca2+ concentration. It had similar effects on calcium elevations induced by forskolin. The effect was more pronounced during the plateau phase than during the initial peak. These effects could help to explain leptin's inhibitory effects on insulin secretion. The inhibition of GLP-I's insulinotropic effects by leptin may be an interesting aspect in the pathophysiology of NIDDM. The existence of an "adipo-insular axis" is suggested, in which leptin represents a negative feed-back signal from the adipose tissue to the endocrine pancreas.

Animals↗
PubMed1991

[A new procedure for lymphocyte depletion of thrombocyte concentrates with immunomagnetic beads].

In a series of pilot experiments we depleted platelet concentrates from contaminating leukocytes by use of immunmagnetic beads. The beads were coated with monoclonal antibodies directed against the leukocyte/lymphocyte antigens CD 2, CD 19 or CD 45. The amount of isolated cells depended on the dose of the used beads and was analogous to the observed decrease of leukocytes in platelet concentrates. The total amount of necessary beads for a complete leukocyte depletion depends on the grade of leukocyte contamination, which shows a high variation among different platelet preparations.

Antibodies, Monoclonal↗
PubMed1991

[Chlorine coatings on skin surfaces. II. Parameters influencing the coating strength].

Although active chlorine compounds have been used for more than 140 years (Semmelweis, 1848) as a skin disinfectant the phenomenon of the "chlorine covers" not earlier than 1988 has been described for the first time (Hyg. + Med. 13 (1988) 157). It deals with a chemical alteration of the uppermost skin layer which comes apparent in an oxydizing action against aqueous iodide. Its origin is chlorine covalently bound in the form of N-Cl functions to the protein matrix of the horny skin. Since the chlorine covers exhibit a persistant disinfecting activity which might be important for practice, the factors influencing their strength have been established. The most important are: the kind of the chlorine system, the concentration (oxydation capacity), pH, temperature and the volume of the used solution, the time of action, the application technique and the state of the skin. Variations of the latter can be observed at different skin areas of one and the same person as well as at the same areas of different persons, and result in differences of the cover strength up to 100%. The stability on dry skin is very good, showing a decomposition rate of approximately 1.2% per hour. However on skin surfaces moistened by sweat (e.g. hands covered by surgeons gloves) the chlorine cover is disingrated much more faster (decomposition rate: 40-50% per hour). Washing with soap as well as the action of alcohols cause virtually no decrease in the cover strength, while wetting by solutions of reducing agents (e.g. thiosulfate, cysteine, iodide) provokes a fast decomposition suitable for removing the chlorine covers.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohols↗
PubMed1990

[Chlorine covers on skin surfaces. I. Determination of the covering strength with the DPD cuvette method].

A new photometric micro method for the quantitative determination of "chlorine covers" on skin surfaces is presented. It is based on the formation of the dye emerging from the reaction of the bound chlorine with iodide and diethyl-p-phenylene diamine (DPD). In contrast to the already described "glove-method" (Hyg. + Med. 13 (1988) 157) it can be applied to all regions of the body and enables a valuation of the specific chlorine cover (micrograms Cl2/cm2). Further features of the method are a small demand of time and work, and--on grounds of the high sensitivity--only a small measuring area (approximately 1.5 cm2) which allows repeated measurements for improving the statistical safety. However, since the different skin areas take up variable amounts of chlorine this can be done only at limited areas. Founded upon a comprehensive error analysis a precision (calculated variation coefficient) of +/- 3-4% for flat and +/- 8-9% for curved (finger tips) skin areas with not too small chlorine covers (greater than 0.3 microgram Cl2/cm2) has been evaluated. Failing a reference method resp. standard areas with known chlorine covers the accuracy of the method could not exactly be ascertained. Owing to an estimation of the most important systematic errors the method might yield results slightly to low (deviation from the true value: approximately -5 to -10%). In spite of this restriction the DPD-cuvette-method is a very useful analytical procedure and the chlorine cover measured herewith and expressed as microgram Cl2/cm2 represents a new skin related parameter, which not only allows an estimation of persistent bactericidal effects on skin surfaces, but also might be useful as an indicator for the roughness of the skin.

Chlorine↗
PubMed1989

[HLA compatibility and susceptibility to habitual abortion. Results of histocompatibility testing of couples with frequent miscarriages].

We have performed class I HLA antigen testing in 42 women with recurrent habitual abortions and in their husbands. The main criterion for inclusion in this group was a frequency of more than two abortions without the known reasons for abortion and without a living child. 29 couples with a least two healthy children and no abortion in the clinical history served as a control group. The data were evaluated in respect to the association of HLA and disease as well as to the level of histocompatibility within the couples. In our results we did not find any significant association between HLA-A, B, C phenotypes and the habitual abortion. On the other hand, we observed a significantly higher level of histocompatibility in the couples with habitual abortions in comparison to the control couples. The frequency of identity in one and more histocompatibility antigens was in the patient group significantly higher than in the control group and as it could be expected by chance, calculated on the basis of antigen distribution within the loci A, B, C in the population in the southern part of the GDR. In no case we have revealed lymphocytotoxic antibodies as a possible cause for miscarriage. Our results are in favour of the hypothesis that a higher level of histocompatibility could be an immunological explanation for the habitual abortions. In addition, this hypothesis was supported by the successful immunotherapy with leukocytes derived from the husband or nonrelative donors.

Abortion, Habitual↗
PubMed1986

Effect of inspiratory volume on intrathoracic pressure generated by an L-1 maneuver.

Since each muscle has an optimal length at which it can generate the maximum tension, an optimal inspiratory volume may exist for producing the maximum intrathoracic pressure during the L-1 maneuver. Intrathoracic pressures were measured in eight healthy men after they inspired various volumes of air and performed the L-1 straining maneuver in a 1-G environment. Both the peak and mean intrathoracic pressures increased at greater inspiratory volumes, except for the mean intrathoracic pressure at the highest volumes. The ability to increase intrathoracic pressure with larger inspiratory volumes may improve +Gz tolerance.

Adult↗
PubMed1983

Activity of myo-inositol-1-phosphate synthase in the epididymal spermatozoa of rams.

Studies of six 8-9-month-old rams showed that the specific activities of myoinositol-1-phosphate synthase (EC 5.5.1.4) were highest in epididymal spermatozoa, intermediate in testis and lowest in epididymal tissue. The activity per spermatozoon decreased from caput to cauda. The levels of activity of myo-inositol-1-phosphate synthase in ejaculated spermatozoa from four 3-year-old rams and the seminal vesicles of two 3-year-old rams were insignificant, but in pooled Sertoli cells from the testes of young lambs, the specific activity was much lower than in epididymal spermatozoa although activity per cell was of the same order of magnitude. We conclude that epididymal spermatozoa contain a significant, if not the major, amount of myo-inositol-1-phosphate synthase activity of the epididymis.

Animals↗
PubMed1968

Shope fibroma virus growth curve in suspended tissue culture.

As a tumour-producing agent, Shope's rabbit fibroma virus (a member of the myxoma-fibroma subgroup of the poxviruses) is endowed with potentialities which differ from those of vaccinia virus. This work attemps to find, by the technique of the one-step growth curve in suspended cells, if the virus replication scheme is similar to other poxviruses. Fibroma virus seems to multiply rather slowly and to a limited level, but the pattern is characteristic of the poxviruses: eclipse phase, exponential multiplication, reduced release of virus in the medium are the main features.

Animals↗
PubMedDate not supplied

[Clinical and immunologic results of immunotherapy with pooled buffy coat transfusions in females with habitual abortion].

In a multicenter study we have evaluated the effect of immunotherapy with pooled buffy coats on women with habitual abortions. 21 women were selected under the same criteria with respect to clinical, immunological and blood banking conditions. All women have had at least two miscarriages with the same partner and no living child (except one case). Additionally, all well-known reasons for abortions were excluded. The couples were tested for HLA-A, B and C antigens as well as for the presence of HLA-antibodies. The couples with recurrent spontaneous abortions suggested a significantly higher compatibility in two or more antigens in comparison to the control couples with children and without any abortion. Before treatment there was no case with cytotoxic HLA antibodies. 10 women received each two pooled buffy coats intravenously before pregnancy at time intervals of 3 weeks. 15 women were treated in early pregnancy until the 28th week of gestation at the same application intervals. In the meantime 10 of 15 women have delivered at term a healthy and mature child with normal weight. Four of 15 are still pregnant in the third trimester of pregnancy. In one case the pregnancy resulted in an abortion. The buffy coat transfusions were well tolerated and led in no case to the formation of antierythrocytic antibodies. 12 of 21 women treated developed HLA antibodies at various time intervals during immunotherapy, mainly with a low titre. In 7 of 10 cases the antibodies occurred in the treatment period before pregnancy, in 5 of 15 cases during pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Habitual↗