Labial Stem Cell Extract Mitigates Injury to Irradiated Salivary Glands.

Stem cell-based therapies could provide a permanent treatment for salivary gland (SG) hypofunction caused by ionizing radiation (IR) injury. However, current challenges for SG stem cells to reach the clinic include surgical invasiveness, amount of tissue needed, cell delivery, and storage methods. The objective of this study was to develop a clinically less invasive method to isolate and expand human SG stem cells and then to obtain a cell-free extract to be used as a therapy for IR-injured SGs. Human labial glands were biopsied, and labial stem cells (LSCs) were expanded by explant culture. The LSC extract (LSCE) was obtained by releasing the cellular components after 3 freeze-thaw cycles and 17,000g force centrifugation. LSCE was injected intravenously into mice that had their SGs injured with 13-Gy IR. Positive (non-IR) and negative (IR) control mice received injections of saline (vehicle control). Three pieces of labial glands (0.1 g weight) could expand 1 to 2 million cells. LSCs had a doubling time of 18.8 h; could differentiate into osteocytes, adipocytes, and chondrocytes; and were positive for mesenchymal stem cell markers. Both angiogenic (FGF-1, FGF-2, KGF, angiopoietin, uPA, VEGF) and antiangiogenic factors (PAI-1, TIMP-1, TSP-1, CD26) were detected in LSCE. In addition, some angiogenic factors (PEDF, PTX3, VEGF) possessed neurotrophic functions. Mice treated with LSCE had 50% to 60% higher salivary flow rate than saline-treated mice at 8 and 12 wk post-IR. Saliva lag time measurements also confirmed that LSCE restored SG function. Histologic analyses of parotids and submandibular glands reported comparable numbers of acinar cells, blood vessels, and parasympathetic nerves and cell proliferation rates in sham IR and LSCE-treated mice, though significantly lower in saline-treated mice. An explant culture method can harvest a large number of LSCs from small pieces of labial glands. LSCE showed clinical potential to mitigate IR-injured SGs.

Estimation and correlation of IC50 for the inhibition of human erythrocyte acetylcholinesterase by cis-diamminediaquaplatinum (II).

The present work addresses the estimation and mode of aquiring fifty per cent inhibition of human erythrocyte membrane-bound acetylcholinesterase (AChE, EC 3.1.1.7) by cis-diamminediaqua-platinum II (DDP), which is presently in clinical trials for use as an antineoplastic drug. It has been recently reported that cisplatin itself has the ability to inhibit the AChE activity in vitro [Al-Jafari, et al, 1995; Kamal and Al-Jafari, 1996]. Therefore, this study was focused on the estimation of the IC50 of AChE inhibition by DDP, and its correlation with reaction times. It was found that 0.0-20.0% and 53.8-94.5% AChE inhibition takes place at 3.0 to 60 minutes after 0.025 and 0.40 mM DDP administration, respectively. The IC50 was proportional to the reaction period, and gave values of 0.057 to 0.918 mMat reaction times ranging from 3.0 to 60.0 minutes, respectively. The DDP has 1025 and 67 times higher inhibitory potency than cisplatin for human erythrocyte AChE at 3.0 and 60.0 minutes reaction time respectively. In the light of these findings, particular attention should be paid to DDP in tumor therapy and its inhibitory effect on AChE must be considered during the decision whether to use it as an antineoplastic drug.

Prevalence of toxoplasmosis in Saudi Arabian camels (Camelus dromedarius).

Serum samples from 227 Saudi Arabian camels were examined for Toxoplasma gondii antibodies by the indirect haemagglutination test, using a microtitre technique. Agglutinations (greater than 2+) occurring at 1:64 dilution were considered positive. A total of 36 (16%) camels were serologically positive for toxoplasmosis, giving titres ranging between 1:64 and 1:8192. The prevalence was much higher in female compared to male camels and in adults compared to young individuals.