Nonspecific effect of Mycograb on amphotericin B MIC.

Mycograb C28Y is a recombinant human antibody fragment thought to target HSP-90 and potentiate amphotericin B (AMB). Absence of in vivo efficacy led us to reevaluate its in vitro activity. Interactions between AMB and Mycograb were investigated using a checkerboard design. Addition of Mycograb or various unrelated proteins, including human serum, resulted in similar decreases in the MIC of AMB. Potentiation of AMB by Mycograb appears to be a nonspecific protein effect.

Endocrine patterns of the estrous cycle and pregnancy of wildebeest in the Serengeti ecosystem.

Despite the importance of the western white-bearded wildebeest (Connochaetes taurinus mearnsi) to the Serengeti-Mara ecosystem, surprisingly little is known about the reproductive physiology of this keystone species. A longitudinal, non-invasive endocrine study was conducted on female wildebeest captured from the Serengeti-Mara migration and maintained for approximately 16 months in large fenced enclosures within the species' natural range. An intact bull was introduced to a female subgroup (n=5), while remaining females (n=10) were unexposed to a male. Fecal progestagen patterns reflected ovarian activity and pregnancy. In non-pregnant animals, luteal and inter-luteal baseline progestagen values differed (p<0.001) over time, thereby allowing identification of recurrent estrous cycles. The average durations of the luteal phase, estrous cycle, gestation, and post-partum anestrus were 14.3+/-0.5, 22.6+/-1.0, 240.8+/-11.7, and 104.1+/-15.6 d, respectively. Annual reproductive patterns indicated a distinctive period of ovarian activity that extended from 13 May through 3 December (203.5+/-29.9 d) with all unmated females displaying from one to 14 estrous cycles. Progestagens were higher (p <0.001) in pregnant (n=4) than non-pregnant (n=10) cows. These data (1) reveal the value of fecal hormone monitoring for establishing the first ever endocrine profiles of female wildebeest in semi-free-living conditions in their native range, and (2) indicate that the species is a seasonal breeder that is polyestrous and a spontaneous ovulator.

Synchronization of oestrous cycles in sable antelope.

Techniques for manipulating the oestrous cycle of sable antelope, Hippotragus niger, were evaluated in a captive population of 24 females maintained at the Smithsonian Institution's Conservation and Research Center in Front Royal, VA, USA. A secondary objective was to demonstrate the effectiveness of fecal steroid monitoring techniques as a non-invasive method of tracking experimental manipulations. Controlled Internal Drug Releasing (CIDR) devices designed for cattle (type B, reduced in length by 5 cm to fit the sable antelope's smaller reproductive tract) were more effective than CIDR devices designed for goats (type G) at delivering progesterone into circulation, and maintained serum progesterone at levels up to 86.1+/-7.8% of normal luteal concentrations in females whose spontaneous ovarian activity had been inhibited with melengestrol acetate. Serum progesterone and fecal progestagen measurements were highly correlated (P<0.05). Synchronization treatments of prostaglandin (PG) F2alpha alone and in combination with modified CIDR-B devices (12-day insertion interval) were both effective in inducing synchronized ovulation, however the PGF2alpha/modified CIDR-B treatment resulted in more precise synchrony and a shorter latency to ovulation than did PGF2alpha alone. In a separate experiment to characterize the temporal relationship between synchronization treatment, behavioral oestrus and ovulation, onset of behavioral oestrus occurred 34.1+/-5.7 h following PGF2alpha/modified CIDR-B treatment. Mean duration of the induced oestrus was 24.9+/-4.3 h. The first detectable rise in fecal progestagens occurred 5.1+/-1.0 and 4.1+/-1.0 days following PGF2alpha/modified CIDR-B treatment in groups of females housed with and without an adult male, respectively, indicating that the presence of a male did not accelerate the onset of the induced cycle.

Genetic effects on the longevity of cultured human fibroblasts. I. Werner's syndrome.

Fibroblast cultures were established from skin biopsies from 4 male Werner's syndrome patients, aged 45-50. Several subcultures were obtained from each primary outgrowth and these were passaged to the end of their in vitro lifespan. Their average longevity was significantly less than control skin fibroblasts, but there was extreme variability amongst parallel cultures. In the most thoroughly studied case, the longevity of 19 subcultures derived from a single biopsy varied from 5 to 26 passages, showing that there was considerable heterogeneity in the growth potential of the cells in the primary culture. Moreover, the growth rate from any one culture was not uniform, since long periods of slow growth were sometimes succeeded by much more rapid proliferation. These features of Werner's syndrome fibroblast populations are not seen in cultures from normal individuals. The longevity of fibroblasts from one progeria patient was also shown to be much shorter than controls. Metaphases from 3 Werner's patients demonstrated a much higher frequency of chromosome abnormalities than in normal fibroblasts and also provided evidence of subclones containing a characteristic 'marker' chromosome.

Genetic effects on the longevity of cultured human fibroblasts. II. DNA repair deficient syndromes.

The lifespan of fibroblasts from genetic syndromes with reduced DNA repair or chromosome stability has been measured. Cells from Bloom's syndrome, Cockayne's syndrome, Fanconi's anaemia and 2 out of 3 cases of ataxia telangiectasia had a significantly reduced growth potential in comparison to controls. In each case the longevity of several parallel populations was measured and the greatest variability in lifespan was observed with Cockayne's syndrome cells. The fibroblasts from 1 ataxia telangiectasia patient and a Friedreich's ataxia patient grew to the passage levels seen in control cultures. The results suggest that repair processes are necessary for cells to achieve their maximum in vitro lifespan, and support the error theory rather than the programme theory of ageing.

Genetic effects on the longevity of cultured human fibroblasts. III. Correlations with altered glucose-6-phosphate dehydrogenase.

The level of heat-labile glucose-6-phosphate dehydrogenase (G6PD) has been measured in skin fibroblast cultures from premature ageing or DNA repair deficient genetic syndromes. The short in vitro longevity of Werner's syndrome, progeria, Cockayne's syndrome, ataxia telangiectasia, Fanconi's anaemia, and Bloom's syndrome cultures was correlated with the appearance of a significant fraction of heat-labile enzyme. Long-lived control cultures contain a low level of altered enzyme until they become senescent. The evidence that heat-labile G6PD molecules are derived from errors in synthesis, or from other causes, is critically assessed. It is shown that normal cells grown in medium containing the antibiotic, paromomycin, which is known to reduce the fidelity of ribosomal translation, produce a significant fraction of altered G6PD.

Genetic effects on the longevity of cultured human fibroblasts. IV. Enhanced growth potential of cystic fibrosis cells.

The in vitro longevity of skin fibroblasts in several parallel cultures from each of 4 cystic fibrosis (CF) patients and 3 control patients was measured by serial passages. The control cultures reached 51-56 passages before growth ceased. 1 CF strain achieved an average of 69 passages and another 64 passages. Both of these longevities are significantly greater than the controls. 2 CF strains had significantly shorter longevities than the controls. The results indicate that the CF gene is expressed in cultured fibroblasts and provide further evidence that there may be more than one form of the disease.

Female-female interactions and social stress in prairie voles.

Trios of prairie voles (Microtus ochrogaster) composed of either two estrous sibling or nonsibling females and one male were monitored via time-lapse videotaping over 72 hr. Social and sexual behaviors were analyzed as a function of trio type (sibling or nonsibling) and fate (survivor or nonsurvivor) across 12-h time blocks. Within nonsibling trios, females that were able to maintain prolonged physical contact with the male within the first 3 days of trio formation later survived and successfully produced litters; females that did not maintain male contact later died of undetermined causes, presumably related to social stress. Frequencies of sexual behavior were similar in both trio types and both surviving and nonsurviving females received equivalent amounts of copulatory stimulation from the male. Sibling groups exhibited higher levels of female-female side-by-side contact; nonsibling groups exhibited greater amounts of female-initiated anogenital sniffing, and female-initiated aggression. Female-female social interactions may be determined by prior familiarity and/or relatedness and may play a dominant role in determining the social organization and mating system of this species.

The susceptibility of Werner's syndrome and other human skin fibroblasts to SV40-induced transformation and immortalization.

In attempts to transform and immortalize human cell cultures, skin fibroblasts from normal donors of different ages, from patients with the premature ageing diseases Werner's syndrome (WS) and progeria (PR), and from donors with the cancer-prone diseases ataxia telangiectasia (AT), Bloom's syndrome (BS) and Fanconi's anaemia (FA), were infected with SV40 virus and their growth monitored thereafter. Lesch-Nyhan (LN) fibroblasts were also infected. SV40-infected cultures from two normal and from WS, AT and LN donors attained a spectrum of transformed properties, high mitotic activity at confluence, presence of T-antigen, anchorage independence and altered morphology. Most of these pretransformed cultures died in the crisis period. However, two cultures from the WS and LN patients survived the crisis period and have now been grown to more than 200 passages. For the LN culture the crisis period was at least 200 days. Both permanent lines retain the properties of pretransformed cells, but differ in their modal chromosome number and ability to grow in methionine-free medium. It can be concluded from these experiments that transformation by SV40 to permanent lines is a rare event in human skin fibroblasts, even when these cells were taken from patients predisposed to form cancers.

Characterization of estrous cyclicity in the sable antelope (Hippotragus niger) through fecal progestagen monitoring.

Fecal progesterone metabolite monitoring techniques were validated for the sable antelope and used to characterize ovarian cycle dynamics and reproductive seasonality in a captive population at the National Zoological Park's Conservation and Research Center. Hormone was homogeneously distributed within fecal samples. Longitudinal fluctuations in fecal progesterone metabolites were consistent with typical luteal phase patterns and corresponded closely with changes in serum progesterone. The lag time from an im injection of progesterone to peak excretion in feces was 16 h. The pattern of births showed a slight peak in the summer (May-July), but year-round endocrine monitoring of six nonpregnant females showed no evidence of seasonality in ovarian activity. Females exhibited 11-14 estrous cycles per year, averaging 24.2 +/- 0.9 days in length. Luteal and interluteal phases were 18.4 +/- 0.9 and 5.8 +/- 0.4 days in length, respectively. Although only a small number of hippotragine antelope species have been studied, data indicate that they exhibit considerable interspecific variability in estrous cycle length and reproductive seasonality and thus may be a useful group for further investigation of factors regulating fertility.