Comparison of Directigen Group A Strep Test with a traditional culture technique for detection of group A beta-hemolytic streptococci.

The Directigen Group A Strep Test (DGAST), a new rapid method of detecting group A beta-hemolytic streptococci directly from throat swabs, was compared with a traditional culture technique for the detection of group A beta-hemolytic streptococci. Five hundred oropharyngeal swabs from pediatric and adult patients were cultured and then processed by using the DGAST. Of the 144 specimens positive by culture, 131 were DGAST positive (sensitivity, 90.9%). Of the 356 specimens negative by culture, 353 were DGAST negative (specificity, 99.2%). Twelve of the 13 false-negative DGAST results were from pediatric patients. One hundred isolates of non-group A beta-hemolytic streptococci were recovered, primarily groups C, F, and G. The DGAST is easy to perform, rapid, sensitive, and very specific for detection of group A beta-hemolytic streptococci directly from swabs. Supplementing the DGAST with a culture on a 5% sheep blood agar plate would enhance detection of group A beta-hemolytic streptococci, especially in pediatric patients.     

Über Krampfpotentiale in Hypothermie

Zusammenfassung Form, Entstehungsort und Ausbreitung der bei Hypothermie spontan entstehenden Krampfaktivität wurden mit der Methode des isolierten Katzenkopfes, der von einer Spenderkatze durchströmt wird, untersucht.Bei fortschreitender Hypothermie traten bei den mit Hexobarbital bzw. Pentobarbital narkotisierten Gehirnen die ersten Krampfpotentiale vorwiegend als Krampfspitzen oder Steilwellen im Rhinencephalon bei einer mittleren Gehirntemperatur von 34° bzw. 35° auf. Beim nichtnarkotisierten Gehirn waren die abgeleiteten Krampfpotentiale vorwiegend polyspike-wave-Komplexe, die ebenfalls zuerst nur im Rhinencephalon bei einer signifikant tieferen mittleren Gehirntemperatur von 31° auftraten.Bei einer mittleren Gehirntemperatur von 30°–18° waren bei den mit Hexobarbital und bei einer mittleren Temperatur von 31°–18° bei den mit Pentobarbital narkotisierten Gehirnen Krampfpotentiale generalisiert über allen corticalen und subcorticalen Strukturen abzuleiten; bei den nichtnarkotisierten Kontrollgehirnen dagegen bei mittleren signifikant differenten Gehirntemperaturen von 28°–16°. Die Generalisierung begann zunächst bei einer oder einigen nicht zum Rhinencephalon gehörenden Strukturen und breitete sich bei weiterer Temperaturerniedrigung bald auf alle corticalen und subcorticalen Strukturen aus. Die in den Versuchen mit Barbituraten signifikant höheren mittleren Gehirntemperaturen für den ersten Beginn von Krampfentladungen im Rhinencephalon und für den Beginn des Stadiums der Generalisierung weisen auf eine durch Barbiturate verursachte Erregbarkeitssteigerung.Bei den narkotisierten Gehirnen waren vorwiegend polyspike-wave-Komplexe und deren Varianten, ferner Krampfspitzen und Steilwellen und deren Formvarianten vorhanden; bei den nicht narkotisierten Gehirnen waren vorwiegend nur polyspike-wave-Komplexe vorhanden.Innerhalb des Stadiums der Generalisierung waren mit einer Häufung zwischen 25° und 20° bei den narkotisierten und unnarkotisierten Gehirnen sowohl isolierte Entladungsserien im Hippocampus und/oder Nucl. amygdalae wie auch generalisierte Entladungsserien über allen untersuchten Stellen des Cortex und Subcortex abzuleiten.Die in Normothermie im Hippocampus zu registrierenden Verletzungspotentiale waren manchmal noch bis zu einer Temperatur von 35°–33° vorhanden. Erst bei weiterer Temperatursenkung traten im Rhinencephalon die anders geformten, durch Hypothermie ausgelösten, ersten Krampfpotentiale auf, die dann bei noch weiterer Temperatursenkung generalisierten.In ergänzenden Versuchen am Ganztier konnte gezeigt werden, daß die durch Hypothermie am isolierten Kopf ausgelöste Krampfaktivität prinzipiell in gleicher Weise beim ganzen Organismus vorhanden ist.Die Ursache für die Auslösung von Krampfpotentialen allein durch Hypothermie kann sowohl eine Erregbarkeitssteigerung wie ein zunehmender Ausfall von hemmenden Vorgängen sein. Beide Mechanismen würden zunächst nur das Rhinencephalon betreffen und bei weiterer Temperaturerniedrigung generalisiert in Erscheinung treten. Ein O₂-Mangel ist als Ursache für die Entstehung der in Hypothermie auftretenden Krampfpotentiale auszuschließen.

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Summary The form, point of origin, and spread of epileptic electrical potentials, which arises spontaneously from the brain during hypothermia, have been investigated using the method of the isolated cat's head perfused by a donor animal of the same species.During progressively increasing hypothermia under hexobarbital and pentobarbital anesthesia the first seizure potentials were preponderantly spikes and sharp waves which arose from the rhinencephalon with an average brain temperature of 34° and 35° C, respectively. In non-narcotized heads the seizure potentials were preponderantly poly-spike and wave complexes, which also arose first from the rhinencephalon at a significantly deeper average brain temperature, namely 31° C.Generalized epileptic potentials were recorded from all cortical and subcortical structures during an average brain temperature of 30° C to 18° C during hexobarbital and 31° to 18° C during pentobarbital anesthesia. In the non-narcotized control brain similar diffuse electrical discharges were observed at a significantly lower average brain temperature, namely 28° to 16° C. The generalization of the epileptic electrical activity begann by spread to one or several areas outside the rhinencephalon and then with further lowering of the temperature to the entire brain. Because the first seizure discharges developed in the rhinencephalon and began their spread to the entire brain at significantly higher average brain temperature during barbiturate narcosis than in non-narcotized brains, it is felt that the barbiturate increased the excitability of the brain.The predominant poly-spike and wave complexes and their variants, and various forms of spikes and sharp waves were present in the narcotized brain. In the non-narcotized brains the poly-spike and wave complexes predominated; the sharp wave variants were infrequent.During the periods when generalized electrical activity was recorded from all parts of the brain, and especially when the brain temperature was between 25° and 20° C in both narcotized and non-narcotized brains, isolated bursts of electrical activity were observed from the hippocampus and/or amygdaloid nucleus and generalized bursts from the entire brain.The injury potentials which developed in the hippocampus in normothermia were sometimes present until the brain temperature had dropped to 35° to 33° C. When the temperature was reduced further the epileptic discharges produced by hypothermia alone, and described before, arose first from the hippocampus and after further reduction in temperature from the entire brain.In supplementary experiments it was uniformly observed that epileptic activity, similar in all ways to that produced in isolated heads by hypothermia, could be produced in intact animals by hypothermia.The cause of release of epileptic discharges by hypothermia alone can as well be explained by an increase in irritability as by a decrease of inhibitory events. Both mechanisms would primarily be concerned only with the rhinencephalon, but with further lowering of the temperature apply to the entire brain. Anoxia does not appear to be the explanation of the epileptic electrical potentials produced by hypothermia.

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Mit 5 Textabbildungen

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.

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Auszugsweise vorgetragen auf dem 12. Internationalen Kongreß der physiologischen Wissenschaften, Leiden 1962 (Proc. Internat. Union Physiol. Sciences, Vol. II, 706; Internat. Congress Series Nr. 48 Excerpta Medica Foundation, Amsterdam 1962).     

Local production of IgA- and IgM-rheumatoid factors in adult periodontal disease

The enzyme-linked immunospot assay was used to enumerate both the number and the frequency of spontaneous IgG, IgA, and IgM immunoglobulin-secreting cells and IgA- and IgM-rheumatoid factor (RF)-producing cells present in the gingivae and peripheral blood of adult periodontitis patients. Cells from 29 patients were incubated on plates coated with human IgG, Fc, or F(ab)₂ fragments and on plates coated with class-specific antihuman antibodies and secreted antibodies were subsequently visualized by means of an immunoenzymatic procedure. The data indicate that (1) IgA-RF- and IgM-RF-secreting cells are frequently present in the gingiva of adult periodontitis patients; (2) production of RF in gingivae of adult periodontitis patients occurs in the absence of demonstrable RF production by simultaneously obtained peripheral blood mononuclear cells, suggesting that local autoimmune reactions may occur in this disease; and (3) lack of correlation between IgA-RF and IgM-RF production in diseased gingiva suggests that the two RF isotypes are regulated independently of each other.     

Caloric compensation in hypothalamic obese rats

The present study explored the influence of pelleted diets on adjustment to caloric dilution in hypothalamic obese rats. Medial hypothalamic lesioned and normal rats were maintained on a high fat diet until the static stage of hyperphagia was reached. They were given three pelleted diets which consisted of undiluted Noyes pellets and Noyes pellets diluted 25 or 50 percent with kaolin. In contrast to previous reports that hypothalamic obese rats do not compensate for caloric dilution of their diet, the obese animals showed as large an increase in food intake on the dilute pelleted diets as did the control animals. These results were interpreted by viewing texture as a dimension of palatability which influences food intake in hypothalamic obese rats.     

Hydrogen sulfide exposure without loss of consciousness: chronic effects in four cases

Adverse effects of acute exposure to hydrogen sulfide (H2S) are well documented, but long-term effects of occupational exposure to low levels of the gas are not. To evaluate effects of such exposure we performed physical, neurologic, psychiatric, and chemosensory (smell and taste) examinations of four workers who were present but did not lose consciousness when the gas was accidentally released at a construction site. None of the four workers tested positive for functional problems, but all met diagnostic criteria for at least three, and up to eight, H2S-induced neuropsychiatric clinical disorders and from zero to two subclinical disorders. All four had abnormal P300 evoked responses (electrical neurophysiologic tests of brain waves). Our data indicate that exposures to even relatively low concentrations of H2S are hazardous. A rigorous epidemiologic investigation of persons who work with H2S is warranted.     

Audiologic findings after stereotactic radiosurgery in nine cases of acoustic neurinomas.

Nine cases of acoustic neurinoma were treated by stereotactic radiosurgery between 1969 and 1974. The follow-up period can now be regarded as sufficiently long for a preliminary evaluation of the results. An arrest of growth or shrinkage of the tumour was observed in 8 of the 9 cases. In one case open surgery was performed 2 years after irradiation and histological examination showed regressive changes of the type expected after irradiation. Audiological examination revealed that in the majority of cases radiosurgery could be performed without causing serious damage to the hearing function. The average hearing loss present before treatment increased on average only 20.0 dB in the most successful 7 cases. None of the patients suffered facial nerve involvement. In small and medium-sized acoustic tumours this method offers a satisfactory therapeutic alternative worthy of consideration.