Effect of contraceptive pills on sexual activity in the luteal phase of the human menstrual cycle

The results of a double-blind placebo study reveal changes of sexual behavior of 51 women followed over three menstrual cycles. Differences in sexual activity during the luteal phase of the cycle (days 18 to 25) were noted. Sexual activity increased for women on contraceptive pills but not on placebo. After examination of the data, hypotheses were rejected that the difference was due to contraceptive pills directly affecting the woman's feeling state or overall activity level. The data are consistent, however, with the following: The presence of endogenous progesterone during natural cycles affects the male so that he does not desire coitus as frequently during the luteal phase. The absence of endogenous progesterone during pill cycles removes whatever restraint progesterone has on coitus. No other interpretation is consistent with the data derived from this study. The influence on the human male may operate via a pheromone as is the case with male rhesus monkeys.This research was supported by funds from the Carolina Population Center and the University Research Council.     

Development of fine structure of spinal cord in monkey fetuses. II. Pre-reflex period to period of long intersegmental reflexes

A series of 13 macaque fetuses of estimated ovulation ages 42 to 51 days (17 to 41 mm) was subjected to behavioral analysis with umbilical cord intact (in and out of the amnion), and to light and electron microscopic analysis of the cervical spinal cord. This period is a critical one in terms of onset and early development of spontaneous activity and of cutaneous reflexes. Behavioral criteria, reinforced by well-defined microscopic characteristics, suggested a grouping of specimens into three major stages, namely, a pre-reflex group (Stage 1: 17–22 mm); a group in the period of onset of primitive spontaneous activity and of precocious local cutaneous reflexes in the trigeminal-cervical region (Stage 2: 24 to 28 mm); and a group characterized by the development of more vigorous activity, spontaneous and otherwise, and of long intersegmental and crossed reflexes (Stage 3: 32 to 41 mm). The evidence suggests that junctional differentiation and occurrance of a cluster of agranular spheroid synaptic vesicles characterize the primitive synaptic knobs which appear on motoneuron dendrites coincident with earliest reflexes. Onset of active long intersegmental reflexes in Stage 3 is coincident with development of axosomatic synaptic knobs, and of F type (flattened) synaptic vesicles in a rapidly increasing fraction of all synaptic bulbs in the motoneuron neuropil. Total volume of all synaptic bulbs increases gradually as a fraction of the volume of the motoneuron neuropil until birth, but a steep increase in proportionate number of F type synaptic knobs occurs in Stage 3.     

A companion therapy program

Through a local community mental health clinic, and with the help of a participating university, volunteers are recruited to work with children from broken or unstable home situations. These Companions see the children once a week on a one-to-one basis for recreational activities. Regular clinic contact is maintained with both the Companion and parents, and the program has become accepted as a part of the clinic's total treatment program. Qualitative impression of results is presented along with some plans for quantification.     

Changes of n-hexane metabolites in urine of rats exposed to various concentrations of n-hexane and to its mixture with toluene or MEK

It is well known that n-hexane produces peripheral neuropathy, and 2,5-hexanedione, one of the metabolites of n-hexane, is thought to be the main causative agent. Recently, the metabolites of n-hexane in urine have been measured by gas chromatography, and 2,5-hexanedione was proved to be useful for the biological monitoring of n-hexane exposure. In the present experiment, we intended to clarify the change of n-hexane metabolites in the urine of rats exposed to various concentrations of n-hexane and to its mixture with toluene of MEK. In the first experiment, five separate groups of five rats each were exposed to 100, 500, 1000, or 3000 ppm of n-hexane, or fresh air respectively in an exposure chamber for 8 h a day. Urinary samples were gathered during exposure, 16, 24, and 40 h after exposure. Half of each sample was analyzed by gas chromatography after hydrolysis with acid and enzymes, and the other half was analyzed without hydrolysis. 2,5-Dimethylfuran, MBK, 2-hexanol, 2,5-hexanedione, and gamma-valerolactone could be identified as n-hexane metabolites in the urine. The main metabolites were 2-hexanol and 2,5-hexanedione. 2-Hexanol was mostly excreted during exposure, while most of the 2,5-hexanedione was excreted after the end of exposure. The amount of metabolites in the urine correlatively increased with the concentration of n-hexane from 100 to 1000 ppm, but the amount of metabolites scarcely increased when the concentration of n-hexane increased from 1000 to 3000 ppm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Age-related changes in the redox status of rat muscle cells and their role in enzyme-aging

The redox status of three biological components capable of undergoing oxidation-reduction reactions, glutathione, NAD and NADP, were determined in muscle tissues of young and old rats. A considerable increase in the relative concentration of the oxidized form, at the expense of the reduced one was found in the old tissue reflecting a significantly less reducing environment than in young cells. The effects of varying the ratio of reduced/oxidized glutathione in vitro on the activity of the enzyme glyceraldehyde-3-phosphate dehydrogenase extracted from young and old animals were compared. It was found that concentrations of GSSG as found in old muscle tissue do not affect enzyme samples extracted from young muscle. The accumulation of oxidized glutathione observed in old cells does not, therefore, directly cause the age-related activity loss of this enzyme.     

Histological and radiographic evaluation of polymethylmethacrylate with two different concentrations of barium sulfate in a sheep vertebroplasty model

Percutaneous vertebral augmentation with PMMA has been widely performed and usually provides good pain relief and stabilization of fractured vertebrae. Adequate visualization of PMMA during injection is desirable to minimize cement extravasation, so contrast agents such as barium sulfate are commonly added to the PMMA. The aim of this study was to evaluate the differences of histology and radiographic visualization when different concentrations of barium sulfate are mixed with PMMA. Six sheep were utilized in this study. Three vertebrae of each animal were exposed via retroperitoneal approach, and a cavity was created and then filled with either 10% or 30% BaSO4/PMMA, or left empty. Vertebrae were harvested and analyzed radiographically and histologically 12 and 90 days after surgery. Average CT value of the 30% BaSO4/PMMA group was 2.4-fold higher than that of the 10% BaSO4/PMMA group. Foreign-body giant cells were recognized around BaSO4particles at 90 days in the 30% BaSO4 group, whereas few particles were recognized in the 10% group at 90 days, or in either group at 12 days. A very mild giant-cell reaction is induced by a higher concentration of BaSO4 in PMMA, but the marked improvement in cement visualization by increased BaSO4 may be important to minimize more serious complications of cement extravasation during PMMA injection.     

Properties of an indirect composite material polymerized with two different laboratory polymerizing systems

The purpose of the current study was to evaluate the performance of two laboratory light polymerization systems used to polymerize an indirect composite (Sinfony). A two-step polymerization system (Visio-Alfa and Beta) and a halogen-metal halide unit (Twinkle MIII) were assessed. The composite was polymerized either with the Visio units or with the MIII unit for different exposure periods. Knoop hardness, water sorption, and solubility in water of the composite polymerized with the following modes were determined: Visio, 15 minutes; MIII, 30, 60, 90, 120, and 180 seconds. Extension of light exposure time to the MIII unit improved the hardness of the composite from 30.5 (30 s) to 40.7 (180 s), whereas hardness obtained with the Visio units resulted in 24.8 (15 minutes). Water sorption and solubility of the composite were greater when it was polymerized with the Visio units than with the MIII unit.     

Application of a preliminary light-curing unit for enhanced bonding between a gold alloy and veneering materials

PURPOSE: To evaluate the effectiveness of a preliminary light-curing unit when it was used in a procedure to bond veneering material to metal. METHODS: Two light-activated composite materials (Artglass and Cesead II) were separately placed onto gold alloy disks (Pontol LFC), and polymerized using one of the following three methods: (1) exposure with a high-intensity laboratory light-curing unit (Hyper LII) for 90 seconds; (2) exposure with a preliminary light-curing unit (Targis Quick) for 20 seconds, followed by exposure with the high-intensity unit for 90 seconds; and (3) exposure with the preliminary unit for 90 seconds, followed by exposure with the high-intensity unit for 90 seconds. Shear bond strengths were determined and compared by analysis of variance and post-hoc multiple comparison intervals. The curing depths of the two materials polymerized with the two curing units were determined using a scraping technique described by the International Organization for Standardization (ISO) 4049 with the aim of evaluating the difference in curing performance between the two units. RESULTS: The group polymerized using the preliminary unit for 90 seconds showed statistically improved bond strengths over the group polymerized without the preliminary unit (P < 0.05) regardless of the materials. Regarding the Cesead II material, both groups polymerized using the preliminary unit also indicated significantly improved bond strength compared with the group polymerized with high-intensity only. Also, curing depth results revealed that the high-intensity unit demonstrated greater curing performance than the preliminary unit for both types of materials examined.