Intracellular bacillary burden reflects a burst size for Mycobacterium tuberculosis in vivo

We previously reported that Mycobacterium tuberculosis triggers macrophage necrosis in vitro at a threshold intracellular load of ∼25 bacilli. This suggests a model for tuberculosis where bacilli invading lung macrophages at low multiplicity of infection proliferate to burst size and spread to naïve phagocytes for repeated cycles of replication and cytolysis. The current study evaluated that model in vivo, an environment significantly more complex than in vitro culture. In the lungs of mice infected with M. tuberculosis by aerosol we observed three distinct mononuclear leukocyte populations (CD11b⁻ CD11c^+/hi, CD11b^+/lo CD11c^lo/−, CD11b^+/hi CD11c^+/hi) and neutrophils hosting bacilli. Four weeks after aerosol challenge, CD11b^+/hi CD11c^+/hi mononuclear cells and neutrophils were the predominant hosts for M. tuberculosis while CD11b^+/lo CD11c^lo/− cells assumed that role by ten weeks. Alveolar macrophages (CD11b⁻ CD11c^+/hi) were a minority infected cell type at both time points. The burst size model predicts that individual lung phagocytes would harbor a range of bacillary loads with most containing few bacilli, a smaller proportion containing many bacilli, and few or none exceeding a burst size load. Bacterial load per cell was enumerated in lung monocytic cells and neutrophils at time points after aerosol challenge of wild type and interferon-γ null mice. The resulting data fulfilled those predictions, suggesting a median in vivo burst size in the range of 20 to 40 bacilli for monocytic cells. Most heavily burdened monocytic cells were nonviable, with morphological features similar to those observed after high multiplicity challenge in vitro: nuclear condensation without fragmentation and disintegration of cell membranes without apoptotic vesicle formation. Neutrophils had a narrow range and lower peak bacillary burden than monocytic cells and some exhibited cell death with release of extracellular neutrophil traps. Our studies suggest that burst size cytolysis is a major cause of infection-induced mononuclear cell death in tuberculosis.

Macrophages patrol the lung to ingest and destroy inhaled microbes. Mycobacterium tuberculosis, the bacteria causing tuberculosis, can survive within macrophages and use them as a protected environment for growth. Macrophages by themselves are poorly equipped to kill M. tuberculosis but may undergo programmed cell death (apoptosis) to limit bacterial replication. Virulent M. tuberculosis has evolved the capacity to inhibit macrophage apoptosis, thereby protecting the replication niche. In previous studies we showed that upon reaching a threshold intracellular number (burst size), virulent M. tuberculosis kills macrophages by necrosis and escapes for spreading infection. The present study was designed to test whether this mechanism seen in vitro operates during pulmonary tuberculosis in vivo. The distribution of M. tuberculosis numbers inside lung phagocytes of mice with tuberculosis conformed to predictions based on the burst size hypothesis, as did the appearance of dying cells. We identified four different types of phagocytes hosting intracellular M. tuberculosis. The distribution of M. tuberculosis load within individual phagocytes and between different types of phagocyte changed over the course of tuberculosis disease. These studies reveal the complexity of host defense in tuberculosis that must be considered as new therapies are sought.

Targeted progesterone supplementation improves fertility in lactating dairy cows without a corpus luteum at the initiation of the timed artificial insemination protocol

The objectives of this study were to determine the effect of supplemental progesterone on fertility in lactating dairy cows lacking a corpus luteum (CL) at the initiation of the timed artificial insemination (AI) program. Holstein cows were subjected to the 5-d timed AI program (d -8 GnRH, d -3 and -2 PGF2α, d 0 GnRH and AI). Cows had their ovaries scanned by ultrasonography on d -8 and those bearing a CL were considered to be in diestrus (DI; n=946). Cows that lacked a CL on d -8 were assigned to remain as untreated control (CON; n=234) or receive 2 controlled internal drug release (CIDR) inserts containing progesterone (2CIDR; n=218) from d -8 to -3, as a single insert has been proven insufficient to modulate fertility in cows without CL. Blood was analyzed for progesterone and estradiol concentrations. Pregnancy was diagnosed on d 34 and 62 after AI. Progesterone concentrations during the timed AI program were lowest for CON, intermediate for 2CIDR, and highest for DI. Supplementation increased progesterone concentrations between d -7 and -3 compared with CON (2.65 vs. 0.51 ng/mL). Ovulation to the first GnRH was not affected by treatment. However, a greater proportion of CON and 2CIDR cows had a new CL on d -3 compared with DI cows (66.7 vs. 61.9 vs. 52.0%). In cows with a new CL, the diameter of the ovulatory follicle was larger for CON than 2CIDR, and intermediate for DI (18.7 vs. 16.5 vs. 17.7 mm). Concentrations of estradiol on d -3 did not differ among treatments; however, DI cows had greater estradiol concentrations at AI compared with CON or 2CIDR cows. Pregnancy per AI was less for CON compared with 2CIDR or DI on d 32 (30.8 vs. 46.8 vs. 49.9%) and 64 (28.6 vs. 43.7 vs. 47.3%), indicating that supplementation with progesterone reestablished fertility in cows lacking a CL on d -8. A greater proportion of nonpregnant CON cows had a short reinsemination interval compared with 2CIDR or DI (11.1 vs. 3.5 vs. 5.7%). Treatment did not affect pregnancy loss between d 34 and 62 of gestation. A single ultrasound exam was effective in identifying a low-fertility cohort of cows based on the absence of CL at the first GnRH injection of the timed AI protocol. Progesterone supplementation with 2 CIDR inserts increased progesterone in plasma to 2.65 ng/mL and restored fertility in lactating dairy cows lacking a CL at the initiation of the timed AI program similar to that of cows in diestrus.

Abstract P1-14-10: Final results of neoadjuvant trial of bevacizumab (B) and trastuzumab (T) in combination with weekly paclitaxel (P) as neoadjuvant treatment in HER2-positive breast cancer: A phase II trial (AVANTHER)

Background: B in combination with T has shown meaningful activity in patients (pts) with metastatic HER2-positive breast cancer. Pathological complete response (pCR) was defined as the absence of invasive disease at the time of histological study and there is a relationship between pCR and disease-free survival (DFS) and overall survival (OS). The complete pathological response rate is between 9 to 34% of patients receiving primary treatment prior to surgery with chemotherapy and when the Herceptin was administrated, a pCR of 39% was reached.

AVANTHER is a Phase II trial of preoperative systemic therapy combining B with T and P in a weekly regimen in HER2 positive breast cancer to assess safety and efficacy of the combination.

Methods: Pts with centrally-confirmed HER2− positive (IHC 3+ or FISH positive) breast cancer (stage II or III including locally advanced) received neoadjuvant chemotherapy (NC) with weekly P (80mg/m2/week) for 12 weeks in combination with weekly T (4mg/kg loading dose and 2 mg/kg maintenance) and B (15mg/kg every 3 weeks) for 4 cycles. After surgery all pts received T (1 year) and liposomal doxorubicin plus cyclophosphamide every 3 weeks (4 cycles); primary endpoint was rate of pathological complete response (pCR) in breast and axilla. For all patients, a tissue sample at baseline as well as at surgery was collected for biomarker analyses.

Results: A total of 44 pts have been enrolled. Median tumor size: 3.9 cm. Nine (21%) pts had stage IIA; 19 (45%) stage IIB; 10 (24%) stage IIIA and 4 (10%) stage IIIB. Twenty-nine (69%) pts had estrogen positive receptors.

Data from surgery of 42 patients from a total of 44 patients enrolled were presented in this abstract, but the final results will be present in the symposium. pCR was achieved in 18 (42.9%) pts. Safety and tolerability were good, with rare adverse events of grade 3 [1 (2.4%) episode of severe hypertension, 1 (2,4%) mucosal inflammation].

We presented the results of relationship between magnetic resonance imaging (MRI) and pCR that is one of the secondary objectives of the study.

100% of the patients without pathologic response had stable disease at resonance imaging. Of all patients who had pCR only 55.6% had complete radiological response.

Conclusions: These data show that the combination of P with T and B without an anthracycline for 12 weeks is very effective as NC in HER2 positive breast cancer pts with a high rate of pCR and minimal side effects.

And the MRI is useful for identifying the persistence of residual disease however it only predicts half of the complete pathological responses

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-14-10.

Medication use in a dual pathology program: Observational study

Introduction

Polyfarmacy is frequent in patients with dual diagnosis.

Aims

To quantify the number and describe the treatments prescribed in a cohort of outpatients with dual diagnosis.

Material and methods

A descriptive and transversal study was performed. Patients with dual diagnosis treated at an Outpatient Drug Treatment Center from January 2005 to December 2009 were included. Data from demographic, clinical and therapeutical variables were gathered once. The instruments used for the diagnosis were EuropASI y SCID-I. The number and type of prescript drugs were related with protocol variables.

Results

The study sample included 80 patients (71,6% men, average age 37,2 ± 9). Psychotic disorders (46.8%) and cocaine dependence/abuse (34.6%) were the most frequent comorbid psychiatric illnesses found. 40.8% of patients were polydrug users. The mean of prescript drugs was 3,06 ± 1,4 and only 14% of patients were on monotherapy. The frequency of drugs prescribed was: 68,4% antidepressant, 63,3% antipsychotic, 55,7% antiepileptic and 36,7% anxiolytic drugs. Older patients ( > 45years) took a major number of prescripted drugs (3,88 ± 1,1). Patients with psychotic disorders took the 43.9% of drugs prescripted (p = 0,042). Patients with benzodiazepine abuse took higher number of prescription drugs (5 ± 1,4;p = 0,003) compared with patients with other dependence or abuse.

Conclusions

Patients with dual diagnosis take high quantity of drugs. Older patients, diagnosis of psychosis and benzodiacepine abuse were related with polydrug prescription. Quantification of medication is recommended for treatment optimisation and avoiding yatrogenic.