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ABSTRACT. Phototherapy of newborn rats (NBR) resulted in a decrease in serum calcium and melatonin levels. Transcranial light penetrance in NBR increased with wavelength. Below 640 nm (penetrance = 6.9%), no hypocalcemic effect could be demonstrated. Shielding the occiput of NBR prevented a decrease in serum calcium during phototherapy and substantially reduced the decrease in melatonin found in unshielded NBR. Intraperitoneal injection of propranolol, an inhibitor of melatonin synthesis, caused a decrease in serum calcium in shaded NBR. In contrast, when melatonin was injected with propranolol a decrease in serum calcium did not occur. Additionally, intraperitoneal isoproterenol before phototherapy protected against a decrease in serum calcium. These data are consistent with an hypothesis that a decrease in serum calcium during phototherapy results from transcranial photic inhibition of melatonin synthesis. (Pediatr Res 22: [414][415][416]1987) Abbreviations NBR, newborn rats IP, intraperitoneal CAP, occipital shield Serum calcium concentration decreases in human infants and NBR exposed to white light at the energy level used in phototherapy for hyperbilirubinemia (5 pW/cm2/nm) (I, 2). This effect is not seen when the occiput is shielded (2), when blue light is used (2, 3), or, in NBR, when exogenous melatonin is given before light exposure (2). Transcranial illumination of the pineal inhibits melatonin synthesis (4), and we have hypothesized that the resultant decrease in serum melatonin might be responsible for the hypocalcemic effect of phototherapy (2).If this hypothesis is valid, it should be possible to demonstrate: 1) a relationship between the transcranial penetrance of light and its effect on calcium, 2) decreased serum melatonin concurrent with decreased serum calcium during phototherapy, and 3) changes in serum calcium after pharmacologic manipulation of melatonin synthesis.We determined transcranial light penetrance and serum calcium levels after exposure to light at 510 nm (blue), 545 nm (green), and 640 nm (yellow). We also measured serum melatonin and calcium in NBR during phototherapy with and without CAP; controls were shaded littermates.

When young rats are exposed to white fluorescent light the concentration of calcium in their serum decreases. This effect is prevented by shielding the occiput, by inhibiting corticosterone synthesis, and by exogenous melatonin. Furthermore, the expected hypocalcemic response to cortisol injection is prevented by melatonin. Light-induced hypocalcemia may result from increased calcium uptake by bone when the blocking effect of melatonin decreases after pineal inhibition by transcranial illumination.

The aim of the present study was to determine the progression rate of periodontal disease in patients treated for localized or generalized mild to moderate adult periodontitis. 52 patients with a mean age of 53.7 years (S.D. 12.6 years) were instructed in optimal home care procedures and exposed to initial periodontal therapy, before reconstructive therapy was initiated. Following completion of the prosthetic procedures, supportive therapy was offered to a limited extent and maintenance visits were irregularly scheduled corresponding to traditional dental care. Clinical periodontal parameters from 4 sites per tooth were assessed at the initial examination, at the time of reevaluation after initial therapy and at the re-examination after 8-years. Full sets of intraoral radiographs from the initial and the 8-year re-examination were analyzed with respect to changes in the radiographic alveolar bone height as a % of the total tooth length. As the result of the home care instructions, the mean plaque index (plaque control record) amounted to 21% at the end of initial periodontal therapy. 8 years later, the re-examination revealed a mean plaque index of 49% and a mean gingival bleeding index of 24%. At the initial examination, the 52 patients presented with an average of 18.7 teeth. During treatment, 26 teeth were sacrificed and 19 teeth were lost over the 8 years of supportive therapy. Bicuspids were the most frequent teeth to be lost over the observation period. As a result of initial therapy, the mean pocket probing depths decreased significantly. However, after 8 years, only minor differences were found when compared to the initial examination.(ABSTRACT TRUNCATED AT 250 WORDS)

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Gastric aspirate, collected from 79 infants within 30 minutes of birth, was subjected to the foam-stability test. The lecithin/sphingomyelin ratio was determined in 27. The results were compared with the incidence of respiratory-distress syndrome as determined independently by different investigators. Of the 59 infants with a positive foam-stability test on gastric aspirate, three had transient respiratory distress, and one the respiratory-distress syndrome; 17 of 22 had lecithin/sphingomyelin ratios greater than 2.0. Of nine infants who had intermediate test results, three were normal, four had transient respiratory distress, and two had the respiratory-distress syndrome. In all the 11 infants with negative foam-stability tests the respiratory-distress syndrome developed. The three gastric aspirates tested in this group had lecithin/sphingomyelin ratios of less than 1.5. These data indicate that the foam-stability test on gastric aspirate is a reliable index of fetal lung maturity in infants whose amniotic fluid is not available.

ABSTRACT. In human infants and newborn rats, white light at the intensity used to treat hyperbilirubinemia lowers serum calcium concentration. Occipital shielding or (in newborn rats) exogenous melatonin prevents this effect. Propranolol, by inhibiting melatonin synthesis, also causes hypocalcemia, which is preventable by melatonin. Metyrapone or adrenalectomy prevents hypocalcemia after light exposure or propranolol. Exogenous corticosterone lowers serum calcium; this is prevented by supplementary melatonin. In adult rats, the change in calcium after light, propranolol, or corticosterone is minimal. After parathyroidectomy or a diet with a high calcium/low phosphorus ratio, the hypocalcemic effect of these three agents is restored. Bone samples removed after light exposure or corticosterone administration show increased calcium uptake; this is blocked by supplementary melatonin in vivo or by addition of melatonin to the incubation medium. We postulated that the hypocalcemic effect of light or propran-0101 was due to an acute increase in corticosterone-mediated bone calcium uptake when circulating melatonin was decreased by reduction of the rate of melatonin synthesis. In our study, pinealectomized rats showed no change in serum calcium after light or propranolol; their hypocalcemic response to corticosterone was greater than that of shamoperated controls. Exogenous parathyroid hormone prevented light-induced hypocalcemia in newborn rats. (Pediatr Res 27: 571-573, 1990) Abbreviations AR, adult rats >I00 g NBR, newborn rats, 7-14 g Pnx, pinealectomized Rach, rachitogenic When human infants (1) and NBR (2) are exposed to white light at the intensity used in phototherapy for jaundice, serum calcium concentration decreases by 0.175-0.225 mmol/L. This can be prevented or reversed by shielding the occiput, but not by using blindfolds (2). In NBR, the hypocalcemic response is accompanied by a decrease in serum melatonin and an increase in serum corticosterone. When exogenous melatonin is given or when endogenous synthesis is sustained by isoproterenol (3) during light exposure, serum calcium does not change (4). Propranolol, which inhibits pineal melatonin synthesis (3), lowers serum calcium in shaded NBR unless exogenous melatonin is provided (4).Corticosterone administration lowers serum calcium concen- 5 tration in NBR; this effect is prevented by simultaneous melatonin administration (2). When corticosterone synthesis is inhibited by metyrapone, serum calcium does not fall during light exposure (2,4). Previous studies (5) have shown an acute increase in bone calcium uptake after corticosterone administration in vivo or addition of the steroid to bone incubation medium in vitro; in both situations, melatonin blocks the effect of corticosterone on bone calcium uptake.From these findings, we derive the hypothesis that hypocalcemia during phototherapy or propranolol administration results from a corticosterone-mediated shift of calcium from interstitial fluid into bone when photic or pharmacologic inhibition of melaton...