Cytophotometry of DNA in serial sections]

DNA of leprosy cells in serial paraffine sections stained after Felgen were studied photometrically in scanning microscope SPM with electron computer Wang 720C. Significant differences in extinction values (up to 30--35%) between individual sections within the same series were revealed. Cumulative results of different series were rather uniform. It was concluded that photometric studies of serial sections should be carried out for reliable determination of DNA.     

Chronobiologic serial sections of several orders

The chronobiologic serial section is described. Its applicability to the analysis of nonequidistant data is emphasized. Its ability to detect and quantify multiple components is discussed and exemplified on simulated series with various amounts of additive Gaussian noise. This least-squares method is discussed in the context of a number of complementary procedures such as complex demodulation and linear-nonlinear least-squares rhythmometry.     

Interpretation of electron micrographs of single and serial sections

A method of securing serial sections for electron microscopy is described. Serial sections present certain anomalies of interpretation of a nature such that a complete and detailed three-dimensional reconstruction of the sectioned tissue cannot be made. These anomalies are discussed, as well as those which have been encountered in the interpretation of single sections. Observations of the following kinds have been made in an attempt to elucidate the interpretation of single and serial sections: differing methods of mounting adjacent sections, observation of the same section by high-angle stereoscopy, and examination of sections which have been shadowed prior to and subsequent to electron microscopy. It is found that the appearance of sections is independent of the choice of side to be placed against the formvar films. Stereoscopy shows that the appearance of fine structures is strongly dependent upon the direction of the penetrating electron beam with respect to the plane of the structures. Stereoscopy, combined with shadowing, shows quantitatively that extensive sublimation of polymer occurs upon normal exposure in the electron microscope. Observation of sections shadowed prior to electron microscopy indicates that varying amounts of material are removed between sections by the action of microtomy; i.e., it is probable that the sum of the thicknesses of several serial sections is considerably less than the total thickness of material removed from the block. It is believed that this effect, combined with the effect of sublimation, aids in explaining the failure of adjacent sections to exhibit continuity in their detailed structures.     

Topographical distribution of purine nucleoside phosphorylase in the human neuraxis

The activity of purine nucleoside phosphorylase was determined at various levels of the human neuraxis in 5 brains and 2 spinal cords, using the method of Lewis and Glantz. The determination is based on the decrease in optical density of guanosine at 252 nm and 40 degrees C, with conversion of this compound to guanine and ribose-1-phosphate by phosphorolysis. Our studies show a fairly uniform distribution of the enzyme in the human CNS, with an average value of 209 mumol of guanosine transformed/min/g of wet tissue. The lowest values are found in the spinal cord and cerebellar grey matter, and highest amounts in the occipital grey and white substance.     

Topographical EEG maps of human responses to odors

The physiological response to seven odors (birch tar, galbanum,heliotropine, jasmine, lavender, lemon and peppermint) was assessedby EEG recordings from 19 scalp loci from 16 young adult females.Topographic maps were constructed from the amplitude spectrain four frequency bands: delta (1–4 Hz), theta (4–8Hz), alpha (8–13 Hz) and beta (13–30 Hz). Eightseconds of representative and artifact-free EEG were selectedfor FFT analysis before onset of odor delivery, and at threetimes after stimulus onset. EEG was also quantified at 30 safter stimulus termination. Subjects differed in their subjective responses to the odors,with the most consistently arousing and strong odors being galbanum,lavender, lemon and peppermint. Heliotropine was notably weak.The most pleasant odors were lemon and peppermint, while birchtar, galbanum and lavender were consistently unpleasant. EEGmap changes occurred in one or more frequency bands in eachsubject in response to one or more of the odors. EEG map changessometimes occurred even with weak odors and even when the subjectseemed unaware of the odor's presence. This was most notablewith heliotropine. Across subjects, the most consistent responses to odors werein the theta band. Analysis of variance confirmed that certainodors caused statistically significant theta increases overthe left anterior group of electrodes. Both right hemispheregroups tended to have significant theta increases. The odorsthat caused the greatest increase in theta were birch tar, jasmine,lavender and lemon. On the other hand, during blank controltrials, theta activity diminished. There was also a significantodor by epoch interaction over the right posterior set of electrodes.Several of the odors caused increased theta at one or more epochs.Lemon caused an immediate increase in theta that abated withtime. Birch tar induced a delayed response that persisted afterthe stimulus was turned off. Jasmine and lavender tended toinduce theta sooner than birch tar, but the effect did not outlastthe stimulus. Increased theta was not associated with EEG signsof drowsiness. We conclude that all odors affected the EEG in at least somesubjects, and all subjects responded to at least some odors.Widespread increase in theta occurred in most subjects duringstimulation with such odors as birch tar, jasmine, lavenderand lemon.     

Ultrastructural reconstruction of Taenia ovis oncospheres from serial sections

The cellular organisation of Taenia ovis oncospheres is interpreted from ultrathin serial sections and transmission electron microscopy following high pressure freezing and freeze-substitution. The surface of a hatched, non-activated T. ovis oncosphere is covered by an oncospheral membrane below which is the tegument bearing microvilli. The basal lamina of the tegument is underlain by broad bands of peripheral somatic musculature. Three pairs of hooks and associated muscles are present in the somatophoric third of the oncosphere. Approximately 19 cells of seven different types were identified which include: (i) a quadri-nucleated syncytium of penetration gland type 1 containing two lateral pairs of cell bodies interconnected by narrow cytoplasmic bridges (PG1); (ii) a quadri-nucleated syncytium of penetration gland type 2 (PG2); (iii) a single-nucleated median mesophoric gland cell; (iv) 10 somatic cells; (v) two germinative cells; (vi) two nerve cells; and (vii) a pair of median somatophoric cells. This study provides a clear understanding of the morphology of T. ovis oncospheres and forms the basis for further investigations into the biology of taeniid oncospheres.     

A cytophotometric and electron-microscopical study on catalase activity in serial cryostat sections of rat liver

Summary The validity of the histochemical procedure for demonstrating catalase activity in cryostat sections of rat liver at the light-and electron-microscopical level was studied cytophotometrically. Incubations in the presence of 5 mm diaminobenzidine, 44 mm hydrogen peroxide and 2% polyvinyl alcohol performed on fixed cryostat sections resulted in the highest amounts of final reaction product precipitated in a fine granular form which was specific for catalase activity. Serial sections processed for electron microscopy indicated that the osmiophilic final reaction product was exclusively localized in the matrix and core of peroxisomes. The relationship between incubation time and the amounts of final reaction product generated by catalase activity as measured at 460 nm in mid-zonal areas of liver lobules showed non-linearity for the test-minus-control reaction because first-order inactivation of the enzyme occurred during incubation. Linearity of the test-minus-control reaction and section thickness was observed up to 8 m. Catalase in rat liver showed a K_m value of 2.0 mm for its substrate hydrogen peroxide when the diaminobenzidine concentration was 5 mm. It is concluded that the procedure for demonstrating catalase activity in serial cryostat sections of rat liver at the light- and electron-microscopical level is specific and can be applied to quantitative purposes. This approach may be useful in pathology, when only small biopsies are available, when the tissue is heterogeneous, and when other histochemical markers also need to be studied in the same material.     

Evolution of human serial pairbonding

Data on divorce taken for all available years between 1947 and 1981 from the Demographic Yearbooks of the United Nations on 58 peoples illustrate that divorce has a consistent pattern. Divorces exhibit a skewed distribution, characterized by the occurrence of the mode early in marriage (with a divorce peak on or around the fourth year) and a gradual, long-tailed decline following this peak. Divorce risk peaks in age category 25-29 for males and age categories 20-24 and 25-29 for females, the height of reproductive and parenting years, and divorce counts peak among couples with two or fewer children. These properties of divorce are unrelated to divorce rate; they occur in societies with both high and low divorce rates. Data on available horticultural and gathering/hunting societies illustrate that divorce also peaks among young couples early in marriage. Remarriage by divorced and widowed individuals of reproductive age is also common cross-culturally. It is proposed that the above four-year modal marriage duration among couples of reproductive age who divorce reflects a hominid reproductive strategy that probably evolved some time after the appearance of Homo in response to increased female "reproductive burden" and functioned to ensure the survival of the hominid infant through weaning. Serial pairbonding during the female's reproductive years had ancestral adaptive advantages, producing the modern cross-cultural pattern of serial pairbonding.