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Biomedical subjects

P Tuohimaa

Publications and source records attributed to P Tuohimaa.

161 records · Page 9Linked to original sources
PubMed1972

Induction of avidin synthesis by RNA obtained from chick oviduct.

RNA was extracted from oviduct, shell gland, and liver of chicks treated with diethylstilbestrol and a combination of diethylstilbestrol and progesterone. Preparations containing 500 or 2500 mug of RNA were put in the oviductal lumen of diethylstilbestrol-treated chicks for 24 hr, and the avidin content of the oviduct was determined by measurement of [(14)C]biotin binding. The results of the present study demonstrate that oviduct RNA from chicks treated with progesterone induces synthesis of avidin in chick oviduct. In contrast, liver or shell gland RNA from chicks treated with progesterone, and liver or oviduct RNA from chicks treated with diethylstilbestrol are incapable of inducing avidin synthesis. The inducing capacity of oviduct RNA is destroyed when it is treated with ribonuclease. It is hypothesized that progesterone induces the synthesis of new species of oviduct RNA, which serve as messenger(s) for avidin synthesis. This hypothesis is offered in consideration of the findings: (i) that the residual amount of progesterone present as a contaminant in oviduct RNA from chicks treated with progesterone is far too low to account for the induced avidin synthesis; (ii) that such oviduct RNA from chicks treated with progesterone induces a slight synthesis of avidin in chick shell gland, which ordinarily does not produce avidin in response to progesterone administration and; (iii) that such RNA added in vitro to minces of oviductal tissues incubated in biotin-free medium for 24 hr induces synthesis of avidin.

Animals↗
PubMedDate not supplied

Induction of avidin in the chick oviduct by tissue damage. Effect of promethazine chloride, CaCl2 and hydrocortisone on local induction.

The local effect of the mechanical induction of avidin by ligature was studied in diethylstilbestrol-primed chicks. The highest induction of avidin was always found in the immediate vicinity of the silk ligature of the oviduct. The locality of the induction was highly dependent on the position of the ligature. The nonligated parts of the ligated oviduct also showed a slight avidin induction. These results indicate a strictly local effect of avidin induction by ligature. An antihistamine, promethazine chloride, has a potentiating effect on the avidin induction by ligature when administered after the ligature. On the other hand, membrane stabilization by hydrocortisone or CaCl2 did not influence the ligature-induced avidin synthesis. On the basis of these results it is concluded that the avidin induction is not mediated by histamine activation or membrane damage.

Animals↗
PubMedDate not supplied

Vitamin D and prostate cancer.

Our recent epidemiological study (Ahonen et al., Cancer Causes Control 11(2000) (847-852)) suggests that vitamin D deficiency may increase the risk of initiation and progression of prostate cancer. The nested case-control study was based on a 13-year follow-up of about 19000 middle-aged men free of clinically verified prostate cancer. More than one-half of the serum samples had 25OH-vitamin D (25-VD) levels below 50 nmol/l, suggesting VD deficiency. Prostate cancer risk was highest among the group of younger men (40-51 years) with low serum 25-VD, whereas low serum 25-VD appeared not to increase the risk of prostate cancer in older men (>51 years). This suggests that VD has a protective role against prostate cancer only before the andropause, when serum androgen concentrations are higher. The lowest 25-VD concentrations in the younger men were associated with more aggressive prostate cancer. Furthermore, the high 25-VD levels delayed the appearance of clinically verified prostate cancer by 1.8 years. Since these results suggest that vitamin D has a protective role against prostate cancer, we tried to determine whether full spectrum lighting (FSL) during working hours could increase serum 25-VD concentrations. After 1-month exposure, there was no significant increase in the serum 25-VD level, although there was a bias towards slightly increasing values in the test group as opposed to decreasing values in controls. There was no significant change in the skin urocanic acid production. The possibility to use FSL in cancer prevention is discussed. In order to clarify the mechanism of VD action on cell proliferation and differentiation, we performed studies with the rat and human prostates as well prostate cancer cell lines. It is possible that 25-VD may have a direct role in the host anticancer defence activity, but the metabolism of vitamin D in the prostate may also play an important role in its action. We raised antibodies against human 1alpha-hydroxylase and 24-hydroxylase. Our preliminary results suggest that vitamin D is actively metabolised in the prostate. Vitamin D appears to upregulate androgen receptor expression, whereas androgens seem to upregulate vitamin D receptor (VDR). This may at least partially explain the androgen dependence of VD action. VD alone or administered with androgen causes a suppression of epithelial cell proliferation. VD can activate mitogen-activated kinases, erk-1 and erk-2, within minutes and p38 within hours. Also, auto/paracrine regulation might be involved, since keratinocyte growth factor (mRNA and protein) was clearly induced by VD. Based on these studies, a putative model for VD action on cell proliferation and differentiation is presented.

Adult↗
PubMedDate not supplied

Prevalence of secretory otitis media in seven to eight year old school children.

One thousand two hundred and seven school children aged seven to eight years were examined in the spring of 1978 in order to determine the frequence of undiagnosed secretory otitis media (SOM). All children were without any subjective ear symptoms. Two and eight tenths percent of the children were found to have SOM. The relation between SOM and the appearance of allergy, the occurrence of earlier otitis media, the occurrence of repeated upper respiratory tract infections and the treatment of earlier middle ear infections are discussed.

Child↗
PubMedDate not supplied

Clinical efficacy and tolerance of bacampicillin and amoxycillin suspensions in children with acute otitis media.

A total of 97 children with acute otitis media were entered into a single-blind, parallel-group study to compare the efficacy and tolerance of suspensions of bacampicillin, given twice daily, with amoxycillin, given three times daily. The daily dosage was about 40 mg/kg body weight in each case and the duration of treatment was 10 days. Patients were examined before the start of treatment, at an early follow-up visit within 2-3 weeks after the start of treatment and at a late follow-up visit 4-6 weeks after the start of treatment. The initial bacteriology revealed a relatively high proportion of Branhamella catarrhalis and a low incidence of pneumococci. In total, 92 patients were evaluated for efficacy at early follow-up, where both bacampicillin and amoxycillin showed equal and good treatment results in approximately 90% of cases. Evaluation at the last valid visit showed that 80-90% of the patients were either cured or improved. The failure frequency tended to be somewhat higher with amoxycillin.

Acute Disease↗
PubMedDate not supplied

Contact allergy to various components of topical preparations for treatment of external otitis.

Patients suffering from chronic external otitis had developed contact allergies to one or more compounds of topical preparations in 40% of 142 tested patients. Neomycin and framycetin caused most of the allergic reactions (16.2%) followed by chinoform (7.0%), chloramphenicol and polymyxin (4.2%). Preservatives of the topical otic preparations such as benzethonium chloride (8.5%), benzalkonium chloride (6.3%) and thimerosal (merthiolate) (5.6%) were also common causes of allergic reactions. An epicutaneous test (patch test) using compounds in topical preparations should be done in cases of prolonged, treatment resistant external otitis.

Anti-Infective Agents, Local↗