Development of the independent function of fetal thyroid glands in the dog in connection with iodothyronine concentrations in pregnant bitches, fetal fluids, and fetal serum

Thyroxine (T₄) and triiodothyronine (T₃) concentrations in pregnant and nonpregnant bitches were measured. The allantoic and amniotic fluid samples were collected separately in the third week of pregnancy, and fetal blood samples were collected in the fourth week of pregnancy. There was no difference between T₄ results in the pregnant and nonpregnant animals, but the measured serum concentrations exceeded the healthy range for normal adults. Serum T₄ concentrations were lower in the fetus than those in adults (P < 0.01). Fetal T₄ concentrations continuously increased and reached 13.38 ± 6.19 nmol/L before birth. The fetal serum T₄ concentrations were lower than the T₄ concentrations in allantoic and amniotic fluid until the seventh week, and the fetal serum T₃ concentrations were lower than those in fetal fluids throughout the pregnancy (P < 0.01). Maximum T₃ concentrations in allantoic and amniotic fluid exceeded the concentrations in the fetal and maternal serum. It is conceivable that the considerable differences between maternal and fetal serum T₄ concentrations in healthy animals are explained by the T₄ impermeability of the placenta. Extremely high maternal T₄ (193.5 nmol/L) in 1 bitch was associated with T₄ concentrations under the detection limit in the fetal fluids and serum suggesting an inhibitory effect. The T₄ concentrations in all the fetal fluids and serum were under the detectable concentration that can be defined by 3.0 nmol/L in that bitch. We have demonstrated that fetal thyroid glands start functioning independently at the same time as thyroid cell formation in the dog, but the overproduction of maternal T₄ may have a suppressive effect on fetal iodothyronine production.

Comparison of the kidney fungal burden in experimental disseminated candidiasis by species of the Candida parapsilosis complex treated with fluconazole, amphotericin B and caspofungin in a temporarily neutropenic murine model

BACKGROUND

The efficacy of fluconazole (FLU), amphotericin B (AMB) and caspofungin (CAS) was tested against three Candida orthopsilosis, three C. metapsilosis and two C. parapsilosis sensu stricto isolates in neutropenic mice.

METHODS

Mice were immunosuppressed by 200 mg/kg cyclophosphamide. Five-day intraperitoneal treatment was started 24 h after infection. Kidney burden was analyzed using the Kruskal-Wallis test.

RESULTS

FLU 10 and 20 mg/kg as well as AMB 1 mg/kg significantly decreased the fungal burden (p < 0.05) for all eight isolates of the three species. CAS 2 and 5 mg/kg were efficacious against all C. orthopsilosis and C. metapsilosis isolates (p < 0.05), but only 5 mg/kg CAS was effective against C. parapsilosis isolates (p < 0.05).

CONCLUSIONS

The efficacy of FLU and AMB against the three species was comparable. Though the activity of CAS was higher against C. orthopsilosis and C. metapsilosis, the current treatment guidelines for C. parapsilosis sensu stricto seem to be applicable to other 'psilosis' species.

Efficacy of a single 6 mg/kg versus two 3 mg/kg caspofungin doses for treatment of disseminated candidiasis caused by Candida albicans in a neutropenic mouse model

We compared the efficacy of single six mg/kg and 2x3 mg/kg caspofungin doses to the traditional one mg/kg daily against C. albicans in a neutropenic murine model. In lethality experiments, all regimens improved survival (p<0.0014 for all three isolates); differences among the treated groups were not statistically significant. We calculated kidney fungal burdens on each study day for six days postinfection using two isolates in two experiments. In the first three days, only the six mg/kg dose produced significant decrease on all study days (p<0.05-0.001), but differences between the three treatment arms disappeared by 4-6 days postinfection (p<0.05 for all isolates on all days).

Immunohistochemical Detection of Progesterone and Cellular Proliferation in Canine Mammary Tumours

Immunohistochemical expression of progesterone and the cellular proliferation marker Ki-67 was assessed in formalin-fixed, paraffin wax-embedded samples from 43 canine mammary tumours. Benign tumours showed high surface membrane progesterone expression (mean 196.42+/-25.91 positively labelled cells per 500 tumour cells) and low cellular proliferation (52.14+/-16.73 positively labelled cells per 500 tumour cells), whilst malignant tumours had low progesterone expression (68.19+/-17.53 positively labelled cells per 500 tumour cells) and higher cellular proliferation (141.72+/-23.65 positively labelled cells per 500 tumour cells), the difference being statistically significant (P<0.005) in both cases. These findings suggest that the majority of progesterone receptors in canine mammary tumour tissue are not associated with bound progesterone. The progression towards malignancy in spontaneously arising canine mammary tumours therefore appears to be associated with a decrease in steroid hormone dependency. Progesterone expression was also noted in the cytoplasm of tumour cells where it may be associated with a cellular repair mechanism. This hypothesis is supported by the finding of significantly higher progesterone content in the cytoplasm of benign tumour cells.

[Different sensitivity to acid reaction of the AIDS virus and virus-producing cells: clinical conclusions]

Sensitivity of the cell-free human immundeficiency virus type 1 (HIV-1) and its producer cells was Studied in acidic media between pH 7.4 and 4.9 vitro. The cytopathic effect, reverse transcriptase activity and p24 antigen production by survived viruses were monitored in indicator cell cultures. It was established that, the cell-free HIV-1 particles are very sensitive to acidity. Between pH 7.4 and 6.0 they loose infectivity gradually, but this process is irreversible under pH 6.0 and subsequent neutralization cannot restore lost infectivity. However, viability, of virus producer cells is hardly affected between pH 7.4 and 4.9, but their ability to release infectious particles is lost gradually, similarly to the case of cell-free viruses. Neutralization of the media after treatment results in gradual restoration of releasing infectious viruses. These data explain that, cell-free HIV-1 looses infectivity in the acidic vagina or does on the skin, but infectivity is preserved in the blood, semen, rectum and breast milk being neutral or slightly alcalic. Virus carrier or producer lymphocytes by any route of infection can survive such protective mechanism of the body.