Murine Inter-Sex Difference in Methylcholanthrene Induced Tumor and its Correlation with NK Activity

Susceptibility to 3-methylcholanthrene (MC) induced tumor development between adult male and female C3H mice at 3–4 mo. old was examined. Animals that were injected (s.c.) with a tumorigenic dose (150 μg/mouse) of MC demonstrated a significant difference in the latent period of tumor development between both sexes. Female mice were more responsive and developed tumors at 3 wks after treatment, whereas, male mice were less responsive as indicated by the longer latent period (10 wks). In order to correlate these data with activity of natural killer (NK) cells, splenic NK activity was measured by 4 hr 51Cr-release assay. The results showed male mice having higher activity: 27 lytic units (LU) in comparison to female ones (3 LU). This was attributed to a decrease in the lytic effect of female NK cells (11%) compared to male mice (20%), since the binding capacity of effector cells to their targets was similar in both sexes (15%), as indicated by single cell assay. The possible role of an immunosuppressive factor (IF) in the sera of female mice was investigated. NK cells from young females demonstrated 33% suppression in activity post culture with sera from 3–4 mo. old female mice.

In conclusion, this study demonstrates a sex-linked tumor development by MC treatment, and correlates this phenomenon with differences of NK activity between young male and female mice as well as in the age-dependent decline of reactivity. A possible immunosuppressive mechanism may be operative in explaining as to why MC is more effective in tumorigenesis in female mice as opposed to males.

A report on emergent uranyl binding phenomena by an amidoxime phosphonic acid co-polymer

XAFS investigations of uranyl binding by an adsorbent polymer reveal different coordination modes than anticipated from previous small molecule studies.

The effects of acidification on human milk's cellular and nutritional content

OBJECTIVE

Fortification of human milk for preterm infants is necessary and a common newborn intensive care practice. Currently, acidified human milk as part of a human milk fortifier is being fed to preterm infants. However, there are little data on the acidification effects on mother's milk. The aim of this study is to determine the effects of acidification on human milk's cellular and nutritional composition.

STUDY DESIGN

One hundred milk samples were collected from eight mothers who had infants in the neonatal intensive care unit. All milk samples were frozen at 4 °C. The frozen samples were thawed and divided into two equal aliquots, control and acidified. The control milk sample had its pH determined while the other sample was acidified to pH 4.5. Each milk sample was examined for pH, white cells, total protein, creamatocrit, lipase activity and free fatty acids.

RESULT

Mean pH of the human milk control was 6.8 ± 0.1 (M ± s.d.) with the acidified milk at 4.5 ± 0.1. Acidification caused a 76% decrease in white cells, a 56% decrease in lipase activity and a 14% decrease in the total protein but a 36% increase in the creamatocrit.

CONCLUSION

Acidification of human milk causes significant changes of the milk's cellular and nutritional components that may not be beneficial to preterm infants.

Effectiveness and cost-effectiveness of sentinel lymph node biopsy compared with axillary node dissection in patients with early-stage breast cancer: a decision model analysis

Background:

Sentinel lymph node biopsy (SLNB) is less invasive than axillary lymph node dissection (ALND) for staging early breast cancer, and has a lower risk of arm lymphoedema and similar rates of locoregional recurrence up to 8 years. This study estimates the longer-term effectiveness and cost-effectiveness of SLNB.

Methods:

A Markov decision model was developed to estimate the incremental quality-adjusted life years (QALYs) and costs of an SLNB-based staging and management strategy compared with ALND over 20 years’ follow-up. The probability and quality-of-life weighting (utility) of outcomes were estimated from published data and population statistics. Costs were estimated from the perspective of the Australian health care system. The model was used to identify key factors affecting treatment decisions.

Results:

The SLNB was more effective and less costly than the ALND over 20 years, with 8 QALYs gained and $883 000 saved per 1000 patients. The SLNB was less effective when: SLNB false negative (FN) rate >13% 5-year incidence of axillary recurrence after an SLNB FN>19% risk of an SLNB-positive result >48% lymphoedema prevalence after ALND <14% or lymphoedema utility decrement <0.012.

Conclusion:

The long-term advantage of SLNB over ALND was modest and sensitive to variations in key assumptions, indicating a need for reliable information on lymphoedema incidence and disutility following SLNB. In addition to awaiting longer-term trial data, risk models to better identify patients at high risk of axillary metastasis will be valuable to inform decision-making.