Ageing and the mismatch repair system

Age-related accumulation of mutations has been extensively documented, and it has been proposed as one of the prominent causes of malignancies in old age. The present review is focused on the particular case of DNA mismatch repair system (MMR), that has drawn increased attention for its possible relevance to malignancy. We also report on our own observations on an age-associated genomic instability that develops with age in the MMR system. Our study was performed on DNA samples that were prepared from peripheral blood cells, obtained at a 10-year interval from young and old human subjects. The two DNA samples from each individual were examined comparatively. The older individuals showed a significantly higher rate of microsatellite instability (MSI) in several loci examined, whereas no difference was found between the paired samples of any of the young subjects. We suggest that this increase in MSI with age may indicate an overall genomic instability in the elderly.     

Laser cryptolysis for the treatment of halitosis.

OBJECTIVE: To evaluate the tonsils as a source of halitosis and to assess the efficacy of laser CO(2) cryptolysis for the treatment of oral bad breath caused by chronic fetid tonsillitis. METHODS: Fifty-three patients with halitosis originating from chronic fetid tonsillitis, who completed laser cryptolysis were enrolled in the study. The origin of halitosis was demonstrated by Finkelstein's tonsil smelling test, which included massaging the tonsils and smelling the squeezed discharge. All patients were treated by laser cryptolysis, an office procedure done under topical anesthesia. Subjective and objective postoperative assessment was based on self-and-family report and clinical assessment. Patients were reexamined 4 to 6 weeks post-treatment, and when the need for further laser treatment was determined. RESULTS: Complete elimination of halitosis required one session in 28 patients (52.8%), 2 sessions in 18 patients (34%), and 3 sessions in 5 patients (9.4%). Follow-up period ranged from 3 to 36 months (mean, 20.8 +/- 8.5 months). No adverse effects or complications were encountered. CONCLUSIONS: After excluding dental or periodontal, sinonasal, oral, pulmonary, or gastroenterological diseases as the origin of halitosis, chronic fetid tonsillitis remains a common cause of halitosis. Patients suffering from halitosis should be treated relying on their examination including Finkelstein's tonsil smelling test. Laser CO(2) cryptolysis is an effective, safe, and well-tolerated procedure for the treatment of halitosis.     

Treatment of severe, drug resistant obsessive compulsive disorder with the 5HT1D agonist sumatriptan

The serotonergic system has been implicated in both the aetiology and pharmacological treatment of obsessive compulsive disorder. In pharmacological challenge tests, mCPP, a 5-HT agonist, with an affinity for 5HT_2C as well as 5HT_1A and 5HT_1D, receptors, was associated with a transient exacerbation of obsessive compulsive symptoms. Chronic administration of mCPP was found to bring about some relief of these symptoms. Sumatriptan is an antimigraine agent, which interacts most potently with 5HT_1D receptors. In the cases to be presented, we report the effects of chronic administration of Sumatriptan to three severe, treatment resistant, OCD patients. Following chronic administration of sumatriptan, these patients, who have been resistant to any former pharmacological treatment, responded with an improvement in their depression and a modest reduction in their obsessive compulsive symptoms.     

Functional changes in platelets during extracorporeal circulation.

An in vitro trauma test was conducted to determine the effects of extracorporeal circulation on platelet count and function. Fresh human blood was circulated in two identical in vitro circuits for six hours at a rate of 500 ml per minute (500 recirculations). One circuit included a G.E.--Peirce membrane lung and the other was a control. Platelet aggregation induced by adenosine diphosphate (ADP), epinephrine, or collagen was studied before and after six hours of perfusion. No important drop in platelet count occurred in the control circuit (Control-C) following bypass, but there was a 20% drop for the lung circuit (Lung-C). Platelet aggregation was reduced by about 30% for the control circuit and 65% for the lung circuit. The large decrease in platelet function accompanied by only a moderate decrease in platelet count is discussed in terms of loss of the youngest and most active platelets, platelet inhibition due to ADP released by red blood cell lysis, and platelet trauma.     

In Vitro Production of Mouse Mammary Tumor Virus in a Mouse Mammary Tumor Ascites Line

An ascites line derived from a spontaneous mouse mammary carcinoma produces, on explantation and cultivation in vitro, large amounts of oncornavirus particles. The biochemical, biophysical, and electron microscopic characteristics of the virions are described. Molecular hybridization and immunological methods identify these virions as mouse mammary tumor virus.     

Periosteal osteosarcoma--a European review of outcome

Periosteal osteosarcoma is a rare primary malignant bone tumour. Treatment is by surgical excision, but controversy remains about the value of chemotherapy. The members of the European Musculo Skeletal Oncology Society (EMSOS) collaborated to produce a dataset of 119 patients. The predominant site for the tumour was the femur, followed by the tibia. All but 2 patients underwent surgery, with 9 requiring amputation and the others having limb salvage. A total of 81 patients had chemotherapy, of whom 50 had neoadjuvant chemotherapy. There was no standard chemotherapy regime, but all patients receiving chemotherapy were given doxorubicin combined with at least one other agent. The overall survival was 89% at 5 years and 83% at 10 years. Eight patients developed local recurrence, of whom 5 died. Survival was related to appearance of local recurrence (P < 0.0001) but no other single factor. The use of chemotherapy was not shown to be a prognostic factor, but was used in two-thirds of the patients in this study.     

The reduced folate carrier gene is a novel selectable marker for recombinant protein overexpression

Folate cofactors are one-carbon donors essential for the biosynthesis of purines and thymidylate. Mammalian cells are devoid of folate biosynthesis and are therefore folate auxotrophs that take up folate vitamins primarily via the reduced folate carrier (RFC). In this study, we showed that the human RFC (hRFC) gene can serve as a novel selectable marker for the overproduction of recombinant proteins. Toward this end, a hemagglutinin (HA) epitope tagged hRFC (hRFC-HA) was introduced into a bicistronic vector (pIRES2-EGFP), upstream of an enhanced green fluorescent protein (EGFP) reporter gene. Chinese hamster ovary cells deficient in RFC activity were isolated and transfected with this construct, followed by gradual deprivation of leucovorin, the sole folate source in the growth medium. Only cells with hRFC-HA overexpression were able to take up leucovorin and thereby survive these selective conditions. Western blot and immunofluorescence analyses confirmed that the hRFC-HA was overexpressed at extremely high levels, properly glycosylated and sorted out to the plasma membrane. This resulted in a approximately 450-fold increase in [3H]methotrexate influx and approximately 100-fold increased sensitivity to methotrexate, relative to untransfected RFC-deficient cells. Flow cytometric analysis consistently revealed that EGFP was overexpressed approximately 100-fold above the autofluorescence level. Overproduction of hRFC-HA and EGFP was stably maintained for at least 2 months in a constant concentration of leucovorin. These results establish a novel RFC-based metabolic selection system for the efficient overexpression of recombinant proteins. Furthermore, the possible implications to subcellular transporter localization and restoration of MTX sensitivity in drug-resistant tumors by RFC-based gene therapy are discussed.     

The Impact of Structured Laboratory Routines in Computerized Medical Records in a Primary Care Service Setting

Inappropriate laboratory ordering is a problem affecting medical systems worldwide. An intervention was called for as a result of increasing laboratory costs. Thus, we aimed to assess the impact of introducing computerized laboratory routines to a computerized primary care setting. The study included 380 primary care physician practices of Clalit Health Service (HMO) southern district (CHS-SD) in Israel, caring for 470,000 members. Consensus laboratory routines order sets were electronically introduced into all physicians’ computerized medical record (CMR) software, after consensus and internal marketing process. The primary findings were that a previously observed annual increase in laboratory test utilization was stopped, a 2% reduction in total number of tests and a 4% reduction in the total number of tests per age adjusted person was observed. In conclusion the wide use of CMRs and communication technology combined with an appropriate organizational process can be used to increase appropriate utilization of laboratory tests.