Effect of Sex, Menstrual Cycle Phase, and Oral Contraceptive Use on Circadian Temperature Rhythms

The circadian rhythm of rectal temperature was continuously recorded over several consecutive days in young men and women on regular nocturnal sleep schedules. There were 50 men, 21 women with natural menstrual cycles [i.e., not taking oral contraceptives (OCs) (10 in the follicular phase and 11 in the luteal phase)], and 14 women using OCs (6 in the pseudofollicular phase and 8 in the pseudoluteal phase). Circadian phase and amplitude were estimated using a curve-fitting procedure, and temperature levels were determined from the raw data. A two-way analysis of variance (ANOVA) on the data from the four groups of women, with factors menstrual cycle phase (follicular, luteal) and OC use (yes, no), showed that temperature during sleep was lower during the follicular phase than during the luteal phase. Since waking temperatures were similar in the two phases, the circadian amplitude was also larger during the follicular phase. The lower follicular phase sleep temperature also resulted in a lower 24-h temperature during the follicular phase. The two-way ANOVA showed that temperature during sleep and 24-h temperature were lower in naturally cycling women than in women taking OCs. A one-way ANOVA on the temperature rhythm parameters from the five groups of subjects showed that the temperature rhythms of the men and of the naturally cycling women in the follicular phase were not significantly different. Both of these groups had lower temperatures during sleep, lower 24-h temperatures, and larger circadian amplitudes than the other groups. There were no significant differences in circadian phase among the five groups studied. In conclusion, menstrual cycle phase, OC use, and sex affect the amplitude and level, but not the phase, of the overt circadian temperature rhythm.     

Morphology of the digestive system of Antarctic nototheniid fishes Received: 24 November 1995/Accepted: 27 January 1996

 Although Antarctic nototheniid fishes are ecologically diverse, this survey of aspects of the anatomy and histology of the digestive system of 25 species showed little interspecific variation in the structure of this system. The gastrointestinal tract is illustrated and all but two species shared a similar pattern of intestinal coiling. The average number of pyloric ceca in most nototheniids was 6–7, with means ranging from 3.0 to 7.6. Reduction in the number of ceca was evident in both phyletically basal and derived species. Intraspecific variation in cecal number was nonexistent in some species, but in others ranged between 2 and 4 ceca. Numerous hepatic ducts, contained within the liver parenchyma, converged on the neck of the gall bladder. The bile duct penetrated the gut wall near the origins of the most dorsally located ceca. The terminal portion of the pancreatic duct paralleled, but did not join, the bile duct. The exocrine pancreas was diffuse and present in intercecal and splenic mesenteries, in the wall of the gall bladder and in tissue near the walls of the bile and pancreatic ducts. Unlike many other teleosts, the liver of nototheniids usually lacked pancreatic exocrine tissue. Nototheniids had a principal pancreatic islet (Brockmann body) and 2–3 accessory islets. Peritoneal melanism was a convergent feature of species living in the water column and probably served to screen the bioluminescence from gut contents.     

The Plaintiff's Attorney and Obstetrics

This paper was presented before a meeting of plaintiffs'' attorneys, including those who specialize in malpractice actions against physicians—the National Association of Claimants'' Compensation Attorneys (NACCA).Doctor Eastman is known internationally for his contribution in the field of obstetrics. In recent years his interests have led him into the field of forensic obstetrics, a complex and difficult subject. Some of these problems are explored by Dr. Eastman in this paper and his comments will be of interest to physicians and attorneys.It is to be hoped that NACCA members benefited by this accurate and scientific presentation.     

DNA repair in cells sensitive and resistant to cis-diamminedichloroplatinum(II): host cell reactivation of damaged plasmid DNA

cis-Diamminedichloroplatinum(II) (cis-DDP) has a broad clinical application as an effective anticancer drug. However, development of resistance to the cytotoxic effects is a limiting factor. In an attempt to understand the mechanism of resistance, we have employed a host cell reactivation assay of DNA repair using a cis-DDP-damaged plasmid vector. The efficiency of DNA repair was assayed by measuring the activity of an enzyme coded for by the plasmid vector. The plasmid expression vector pRSVcat contains the bacterial gene coding for chloramphenicol acetyltransferase (CAT) in a configuration which permits expression in mammalian cells. The plasmid was transfected into repair-proficient and -deficient Chinese hamster ovary cells, and CAT activity was subsequently measured in cell lysates. In the repair-deficient cells, one cis-DDP adduct per cat gene was sufficient to eliminate expression. An equivalent inhibition of CAT expression in the repair-proficient cells did not occur until about 8 times the amount of damage was introduced into the plasmid. These results implicate DNA intrastrand cross-links as the lesions responsible for the inhibition of CAT expression. This assay was used to investigate the potential role of DNA repair in mediating cis-DDP resistance in murine leukemia L1210 cells. The parent cell line L1210/0 resembled repair-deficient cells in that about one adduct per cat gene eliminated expression. In three resistant L1210 cell lines, 3-6-fold higher levels of damage were required to produce an equivalent inhibition. This did not correlate with the degree of resistance as these cells varied from 10- to 100-fold resistant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Renal glomerular evolution in Antarctic notothenioid fishes

Light and electron microscopy were used to document the degree of glomerular development in 10 species of Antarctic notothenioid fishes. When combined with results of previous studies, data revealed that 16 of 20 species inhabiting subzero sea water were aglomerular. One subantarctic and two temperate species were pauciglomerular, and an additional temperate species had a moderate number of glomeruli. Renal corpuscles were variable in number and diameter among the pauciglomerular species, and most had few patent glomerular capillaries. Radiolabelled markers indicated that the glomerular filtration rate was low in the pauciglomerular Notothenia angustata , ranging from 0.005 to 0.124 ml h⁻¹ kg⁻¹ in eight specimens. Arterial perfusion of Microfil demonstrated that arteries supplying aglomerular and pauciglomerular kidneys were confined largely to the periphery of the organ, and glomerular capillaries were absent or few in number. As ancestral notothenioids probably had glomerular kidneys, data from 20–25% of the fauna suggest that there has been an evolutionary loss of glomeruli in many species. The pattern of glomerular reduction is consistent with the hypothesis that the selective advantage of aglomerularism is in the urinary conservation of small molecular weight antifreeze glycopeptide compounds that are vital to survival in sub-zero Antarctic waters.     

Extensive deletions in the Q region of the mouse major histocompatibility complex

By use of Southern blot analyses and low copy number probes, the fine structure of the Q region of the mouse major histocompatibility complex was studied in more detail. With a probe recognizing the even-numbered genes Q4, Q6, and Q8, it was evident that Q4 and/or the regions flanking Q4 are polymorphic, whereas Q6 and Q8, and their flanking regions are nonpolymorphic. Perhaps the most noteworthy finding is that at least two strain haplotypes, H-2 ^k and H-2 ^f, possessed extensive deletions in the Q region. The most striking deletion was found in the H-2 ^f haplotype, where the QI through Q9 genes appear to be missing. Because of these extensive deletions the functional importance of the Q region is questioned.     

Reevaluation of interaction of cis-dichloro(ethylenediamine)platinum(II) with DNA

Intrastrand cross-links represent the majority of modifications in DNA resulting from interaction with the cancer chemotherapeutic drug cis-diamminedichloroplatinum(II) (cis-DDP). These adducts were recently characterized although several discrepancies remained to be resolved. In these studies, [3H]-cis-dichloro(ethylenediamine)platinum(II) (cis-DEP) was used because of the convenience of the radiolabel; this analogue produces adducts at identical sites in DNA as cis-DDP. Both drugs platinate the following sequences in DNA: GG, 65%; AG, 25%; GNG, 6%. The adduct at AG sequences invariably has adenine on the 5'-terminus of the dimer. The present enzyme digestion protocol included P1 nuclease, which produced complete digestion rather than as previously reported. The frequency of platination at GG was too high to be explained by an initial monofunctional platination at any guanine. However, direct bifunctional attack preferentially at GG was obviated because monofunctional adducts could be trapped with thiourea at short time periods. After short incubations, with cis-DEP and removal of unreacted drug, the monofunctional adducts slowly rearranged to bifunctional adducts. It is suggested that this evolution of adducts may result from the drug "walking" along the double helix, a phenomenon that does not appear to occur in single-stranded DNA.     

The role of DNA repair in resistance of L1210 cells to isomeric 1,2-diaminocyclohexaneplatinum complexes and ultraviolet irradiation

Resistance to cisplatin in several murine leukemia L1210 cell lines is due to enhanced DNA repair. Other platinum complexes, particularly those containing 1,2-diaminocyclohexane (DACH) are of interest as they effectively kill both sensitive (L1210/0) and cisplatin-resistant (L1210/DDP) cell lines. An L1210/DACH cell line has been developed that is preferentially resistant to DACH-Pt complexes. In the current experiments, we investigated the role that DNA repair has in resistance to DACH-Pt compounds. The DACH ligand exists in 3 isomeric forms which exhibit markedly different activities in the various resistant cell lines. Generally, R,R-DACH-Pt was the most effective isomer. DNA repair was assayed by host-cell reactivation of platinated pRSVcat. DNA damage induced by all the isomeric DACH-Pt-SO4 complexes markedly reduced CAT expression in sensitive L1210/0 cells. One adduct per transcribed strand of the cat gene inhibited CAT expression demonstrating that the sensitive cells exhibited no detectable DNA repair. All the resistant cell lines reactivated the plasmid DNA whether damaged with cisplatin or any of the 3 DACH-Pt isomers. Therefore, resistance to both cisplatin and DACH-Pt appears to be mediated by enhanced DNA repair, but the level of reactivation of the transfected plasmid did not correlate with the toxicity of each analogue. These results suggest that some additional event(s) is responsible for the substrate specificity of repair of genomic DNA. These resistant cell lines also exhibited resistance to UV irradiation but this was much less than, and did not correlate with the degree of resistance to either cisplatin or DACH-Pt. However, there was a good correlation between resistance to UV irradiation and reactivation of UV-damaged plasmid DNA. This enhanced reactivation suggests that enhanced repair may be the sole reason for the resistance to UV irradiation.     

Transitory acidification of semen as a potential method for the inactivation of some pathogenic microorganisms. Effect on fertilization and development of ova in superovulated heifers

The fertilizing capacity of transitorily acidified semen was investigated with respect to using acidification as a method for destroying or inactivating acid labile pathogenic microorganisms in semen prior to freezing. Ejaculates diluted 1:1 with phosphate buffered saline (PBS) were acidified to pH 5.0 for 2 or 5 minutes before being returned to their original pH. They were then frozen by commercial methods and used to artificially inseminate superovulated heifers. A total 739 ova and embryos was collected from 119 inseminated donors. The fertilization rate was 88%, and 78% of the embryos were of transferable quality. Semen acidification had no apparent effect on the post-thaw percentage of intact acrosomes.