Relations between axon length and axon caliber: Is maximum conduction velocity the factor controlling the evolution of nerve structure?

A search was made for any existent relationship between the length of a nerve fiber and the caliber of its axon. This was done in the hope of defining morphological parameters useful for assessing conduction time.Four fiber populations were examined: (1) phrenic fibers in rat and rabbit during different phases of body growth; (2) phrenic fibers of mature animals of greatly different body size including mouse and cow; (3) rat intercostal nerves which vary in length by a factor exceeding 5 due to the funnel-shape of the thorax; and (4) ventral root fibers of the cow.In all of these fiber populations, there was no evidence for a direct relationship between the length of a fiber and its caliber. Rather, a tendency was noted for fiber caliber to approach certain ceilings independent of length.These data, seen in conjunction with other information on fiber structure, cast serious doubt on the widely accepted concept that maximum conduction velocity is the factor controlling nerve structure. A much more likely factor controlling the structure of myelinated nerve fibers is the capacity to modulate information by frequency coding of impulses.     

Microbiological investigations on cryopreserved human semen

Primary mycological contamination was studied in 565 random human ejaculates. After sperm preservation at low temperature, secondary mycological contamination of 55 of the ejaculates was investigated. 25 ejaculates were cryopreserved with and without antibiotics and examined bacteriologically before and after different phases of cryopreservation. Furthermore, semen samples of several donors were inoculated with suspensions of different concentrations of yeasts and with the test bacteria Escherichia coli K 12 and Staphylococcus aureus SG 511. Microbiological results were then compared before and after cryopreservation. The following results were obtained: 1.9.8% of samples showed primary mycological contamination (1.9% with Candida albicans). 2. Cryopreservation reduced the concentration of fungi by more than 90% on average. 3. Only one semen sample was contaminated with bacteria (Staphylococcus aureus haemolyticus and Streptococcus nonhaemolyticus). Non-pathogenic bacteria were found in 11 ejaculates (Micrococcus luteus in 5 samples and Staphylococcus epidermidis in 6 samples), and contamination was largely unaffected by cryopreservation, even in the presence of antibiotics. 4. Test bacteria inoculated into semen were not influenced by the addition of antibiotics to the cryoprotective medium.     

Urge incontinence in the elderly – supraspinal reflex incontinence

World Journal of Urology -     

Laser-assisted removal of a foreign body in the bronchial system of an infant

Background and Objective: Foreign body aspiration is an important cause of acute respiratory distress in children. Removal by use of rigid tracheo-bronchoscopy under general anesthesia is usually the treatment of choice, but this technique is sometimes unsuccessful. Thoracotomy in these instances often cannot be avoided. Study Design/Patients and Methods: Case report with review of the literature. The patient was 19 months old with an aspirated foreign body. A Neodym:YAG laser with a special small-size delivery system was inserted into the rigid “baby” bronchoscope. The NeodymiumrYAG laser with a wavelength of 1,064 nm and a Helium-Neon 630 nm light guide provided an aiming beam to weaken and cut the aspirated chicken bone. Results: The foreign body could be easily removed with a regular biopsy forceps. Conclusion: We discuss a patient in whom laser-assisted rigid tracheobronchoscopy obviated the need for thoracotomy. © 1995 Wiley-Liss, Inc.     

Selection of Filters and Evaluation In Vitro of the Selective Dual Filtration Artificial Kidney, SEDUFARK

Transport properties of different artificial kidney membranes have been studied employing substances with molecular weights ranging from 60 daltons (urea) to 62,000 daltons (dextran). The results from these studies were used to select filters for the SElective DUal Filtration ARtificial Kidney, SEDUFARK.
Selection criteria for filters to be used in long-term clinical trials with SEDUFARK were based on biological tests showing toxicity of large molecular weight substances in uremic blood plasma and clinical advantages of returning middle molecular weight substances to the patient. The filters selected were used for evaluation in vitro of the complete SEDUFARK system. The results confirmed a theoretical analysis of this system, demonstrating that selective removal of substances within given molecular weight ranges from uremic blood plasma is feasible with a combination of commercial filters. The efficiency of the system, however, is limited due to the "cut-off' characteristics and hydraulic permeabilities of membrane types currently available.     

Diprafenone for treatment of Wolff-Parkinson-White syndrome

Summary The effect of intravenous (1.5 to 2.0 mg/kg body weight) and oral (300 to 375 mg/d) diprafenone was studied in 15 patients with the Wolff-Parkinson-White syndrome and symptomatic supraventricular tachycardia. Intravenous application of diprafenone significantly increased atrioventricular nodal conduction time as well as the effective refractory periods of the right ventricle and the accessory pathway in both the antegrade and retrograde directions. Antegrade conduction block in the accessory pathway occurred in two patients after the dose was increased to 2.0 mg/kg body weight. Intravenous diprafenone suppressed the inducibility of supraventricular tachycardia in two patients, but the tachycardia cycle length was significantly increased in all other patients. Fourteen patients were treated with oral diprafenone, and 11 were asymptomatic during a 17-month follow-up, two of these after the dose had been increased to 375 mg/d. Oral therapy had to be withdrawn in two patients because of adverse gastrointestinal side effects and in one because of recurring bronchospasm.     

Buchbesprechungen

Ohne Zusammenfassung

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Buchbesprechungen

     

Bestimmung von Nitrosobenzol im Blute

Zusammenfassung Durch Extraktion mit Tetrachlorkohlenstoff, Diazotierung in Eisessig und Kupplung mit -Naphthyläthylendiamin konnten kleine Mengen von Nitrosobenzol im Blut photometrisch bestimmt werden.     

Resorption von Äthylenglykoldinitrat durch die Lunge

Zusammenfassung Die Aufnahme von Äthylenglykoldinitrat aus der Luft durch die Lunge wurde an Ratten mit radioaktivem Äthylenglykoldinitrat gemessen.Bei Konzentrationen von 133–428 mg Äthylenglykoldinitrat je m³ Luft wurden im Mittel 20% des mit der Atemluft in die Lunge eingebrachten Äthylenglykoldinitrats resorbiert.     

How disabled are patients with somatoform disorders?

The purpose of this study was to evaluate the level and quality of psychosocial disabilities in patients suffering from somatoform disorders (SFD). Of 221 patients referred for psychiatric and cognitive-behavioral inpatient treatment, 37 were diagnosed according to DSM-IV as having SFD, 56 as pain disorder, 70 met the criteria for the subsyndromal form of SFD called the “Somatic Symptom Index” (SSI). The control group consisted of 58 patients with other mental disorders. All patients completed the Dysfunctional Analysis Questionnaire (DAQ) which measures social, vocational, personal, familial, and cognitive disabilities on psychometric scales. The results showed substantial disabilities in all somatoform subgroups; however, the levels and patterns of dysfunction in these patients were not statistically different from those in the control group. Impairment was generally more severe when patients had a comorbidity of somatoform and affective disorders. It is concluded that SFDs are associated with marked psychosocial disabilities similar to those seen in other mental disorders. The strongest predictor for psychosocial dysfunction is the comorbidity of somatoform with affective disorders, but not with anxiety disorders.