Chemicals in laboratory room air stimulate olfactory neurons of female Bombyx mori.

Laboratory air contained odorants that elicited electrophysiological responses in female Bombyx mori antennae. Air entrainments on charcoal filters, extracted with CS(2) and subsequently with acetone, were analyzed by coupled gas chromatography (GC)-electroantennogram (EAG) as well as by GC-mass spectrometry. The CS(2) extract contained 12 EAG-active peaks from which benzaldehyde, octanal, limonene, 1,8-cineol, methyl benzoate, nonanal, decanal and geranyl acetone were identified. In the acetone extract we identified eight EAG-active peaks as phenol, nonanal, 2-ethylhexanoic acid, octanoic acid, benzoic acid, nonanoic acid, decanoic acid and dimethyl phthalate. The concentrations of benzoic acid and benzaldehyde present in laboratory air were determined. The origin of the substances and importance of such odorants in laboratory air for the interpretation of physiological experiments on the olfactory system is discussed.

The major histocompatibility complex and the chemosensory signalling of individuality in humans.

The chemosensory identity of mice and rats is determined partly by polymorphic genes of the major histocompatibility complex (MHC). In inbred strains of mice, as well as in seminatural populations, MHC-associated mating preferences selectively influence reproductive success, thus serving to promote heterozygocity in the MHC. In order to determine whether MHC-associated chemosignals are present in humans, two studies were conducted. In a first study, olfactory identification of MHC-associated chemosignals was conducted on 12 trained rats' responses to the urine odors of humans. In a second study, MHC-associated olfactory cues in humans were analyzed by means of gas chromatography. The results indicate that the urine odors of humans are associated with the MHC and demonstrate that the profile of volatile components in the urine odors shows some association with the MHC. Furthermore, results show that a profile of some specific components, as well as a few ubiquitous volatiles, constitutes MHC-associated odor signals in humans.

Fractionation and bioassay of human odor types.

Human urine samples were fractionated to examine the contribution of volatiles to the individual body odor. The samples were obtained from 4 male donors and fractionated using a vacuum technique. The volatiles from the chemical fractions were analyzed using the CLSA technique and gas chromatography. Thereafter, these fractions were tested in a computer-controlled olfactometer by trained rats. Although the rats were able to discriminate the distillation residue, they could not recognize the urine odor in the distilled fraction. The results of gas chromatography indicate a continuous release of volatile constituents in the distillation residue.

GC profiles of volatile constituents from human urine obtained by closed loop stripping, purge and trap technique and simultaneous stem distillation-extraction.

Different techniques like "closed loop stripping" [CLSA], "purge and trap" [PTI], and continuous steam distillation extraction [SDE] were used to establish GC profiles of major histocompatibility complex-associated volatile constituents of human urine and statistically evaluated for reliability. Of the three methods investigated, PTI appeared to be superior for the detection of very volatile substances, whereas SDE was the most efficient one with respect to yield. A number of short to medium-chain ketones, 4-hydroxy-3-methoxy-styrene, menthol and nicotine were identified in preliminary analyses.

[Rabies in cattle]. / Zur Tollwut beim Rind.

Diagnostic results of the post mortem examinations of the brains of 99 rabies-suspected--but actually not infected--cattle are reported. In 19 cases listeria encephalitis was stated. Furthermore non-purulent encephalitis 9 X, including 1 X malignant catarrhal fever of cattle and 2 X mucosal disease; purulent encephalitis 1 X; corticocerebral necrosis 1 X and arterial sclerosis 1 X were diagnosed. 68 cases proved to be no cerebral disease. By means of the presented diagnostic results and literature, peculiarities of rabies in cattle are discussed in view of differential diagnosis, and practical hints are given.

[Differential postmortem diagnosis of rabies in cats]. / Beitrag zur postmortalen Differentialdiagnose der Tollwut bei Katzen.

300 cats, sent in for rabies diagnosis, which were obviously not infected, have been further examined with regard to their causes of disease and death. Traumata, uremia and panleucopenia have been observed most frequently. As expected, affections of the central nervous system often have been stated. The results of our investigations have been compared with autopsy statistics on rabies-unsuspected cats, published in literature. Furthermore the preliminary reports have been examined and compared with the anamnesis of 214 rabies-positive cats. The information of preliminary reports on rabies-negative cats and their pathological diagnosis has been discussed in the context of differential diagnosis.