Ultrasound bone measurements in pre-adolescent girls: interaction between ethnicity and lifestyle factors

AIM

We obtained calcaneal ultrasound measurements in 198 girls between 7.5 and 11.7 y of age, representing ethnic groups (black [n = 80], white [n = 41], mixed ancestral origin [n = 77]) in South Africa.

METHODS

Anthropometry was assessed. Demographics, physical activity, habitual dietary calcium intake and pubertal development were quantified by questionnaires. Broadband ultrasound attenuation (BUA) and speed of sound (SOS) of the left calcaneus were measured. Girls in Tanner breast stage 5 and/or those menstruating were excluded from analysis.

RESULTS

Black girls were lighter than white girls (31.4 +/- 7.8 vs 34.8 +/- 7.5 kg; p < 0.05), and shorter than girls of mixed ancestral origin (1.29 +/- 0.08 vs 1.34 +/- 0.07 m; p < 0.001) and white girls (1.35 +/- 0.07 m; p < 0.001), after adjusting for age. Reported calcium intake scores were higher in black than white girls (21.6 +/- 11.1 vs 16.1 +/- 8.4; p < 0.01). Total peak bone strain score (TPBSS) was higher in white compared to black girls (6.8 +/- 4.8 vs 5.0 +/- 4.7; p < 0.05), while walking energy expenditure (MET h/wk) was higher in black girls compared to the other groups (p < 0.001). BUA and SOS were higher in the black girls (59.6 +/- 13.7 dB/MHz; 1575.1 +/- 22.6 m/s; p < 0.001) and girls of mixed ancestral origin (59.0 +/- 12.5 dB/MHz; 1567.8 +/- 26.1 m/s; p < 0.01) than in the white girls (50.4 +/- 8.7 dB/MHz; 1552.1 +/- 19.5 m/s). Co-varying for age and weight did not affect these results. Walking energy expenditure (r = 0.20) and calcium score (r = 0.17) were correlated (p < 0.05) with SOS for the whole group.

CONCLUSION

Ultrasound parameters were lower in the white compared to the black girls, who consumed more calcium on average, but who were lighter, shorter and performed less impact activity. This suggests that interactions between ethnicity and lifestyle factors determine bone quality in premenarcheal girls.

Toxicological evaluation of long-term intravenous administration of amitraz in horses

With the aim of determining the possible toxicity of amitraz after its prolonged use in horses, six English Thoroughbred horses received intravenous injections of amitraz (0.05, 0.10 or 0.15 mg/kg) weekly for four months, constituting the experimental group. Eight other animals (control group), via the same route following the same drug administration schedule and period of time, received the vehicle, dimethylformamide. At the end of this period, blood was collected from all the animals, and a comparison was made of the means of the values obtained for the various blood analyses: complete hemogram, alkaline phosphatase, gamma-glutamyltransferase, blood urea nitrogen, lactate dehydrogenase, aspartate aminotransferase, creatine phosphokinase, glucose, albumin, total protein, creatinine, Na+ , K+, Cl- and CO2. The results for the biochemical characteristics showed that only the mean value for urea of the animals submitted to treatment with amitraz was significantly different than the mean value obtained for the control group. The analyses of the hematological characteristics showed that no significant differences between groups were observed. Similarly, the measurement of blood electrolyte levels demonstrated that long-term treatment with amitraz did not cause significant changes in the variables analyzed. The results indicate that amitraz, given in the doses employed in this study, did not show signs of inducing toxic effects in vital organs, even after prolonged administration.

Treatment of murine cutaneous melanoma with near infrared light

Treatment of cutaneous melanoma (M-3 and B16-F10 implanted in mice) with rapidly-scanned, tightly-focused near infrared light elicits selective destruction of tumor tissue. A single laser treatment yielded complete eradication in >90% of B16-F10 tumors with thicknesses of approximately 3 mm; amelanotic M-3 tumors proved less responsive (ca 25% clearance rate). In addition to local tumor destruction, laser treatment of B16-F10 tumors in immunocompetent mice stimulated enhanced cytokine levels (interleukin-2 and interleukin-10) within treated tumor tissues and rejection of tumor cells upon a subsequent challenge dose. Such an antitumor immune response may lead to improved outcomes at both the treatment site and at sites of distant metastasis.

Field measurements of electromagnetic interference in hearing aids

This investigation was a preliminary field study to determine the acoustic and perceptual characteristics of hearing aid distortion generated by digital wireless telephones, the usability of the telephones under field conditions, and the extent of bystander interference under field conditions. A two-channel analog-to-digital converter was used to monitor voltages generated by an acoustic (real-ear) and electromagnetic probe. Digital recordings of interference and speech plus interference were made on a laptop computer. Fifty-three hearing aid wearers listened to interference and speech plus interference through personal communication service 1900 and time division multiple access digital wireless telephones and rated them in terms of annoyance experienced and usability of the wireless telephone. Ratings of annoyance were also done for the bystander condition. Approximately 80 percent of the sample rated the telephones as unusable; on the other hand, 70 to 90 percent experienced no annoying interference from telephones being used by another person seated nearby (bystander condition).

Practical information for audiologists on access to wireless telephones

Analog cellular telephone service is being phased out in favor of digital wireless services, which are less accessible to people with hearing loss. As a result, audiologists can expect to receive an increasing number of inquiries from clients about using wireless telephones with hearing aids and other assistive technologies. In this article, the underlying transmission technology, telephone handset, roaming, and current solutions to accessibility problems are described. Public policy affecting the accessibility of wireless telephones to people with hearing loss is explained. Alternatives to wireless voice services are explored, and resources for information in a quickly changing industry are provided.

Effect of amitraz and xylazine on some physiological variables of horses

The effect of the intravenous injection of amitraz (0.1mg/kg) to horses on cardiac activity, respiratory rate, intestinal motor activity, rectal temperature, sweating and masticating was evaluated and compared to the effect of intravenous administration of xylazine (1mg/kg, iv) on heart rate, respiratory rate and intestinal activity. Amitraz caused a significant decrease in heart activity, respiratory rate and intestinal movements, but these effects were not as pronounced as those caused by xylazine. Amitraz also caused a significant relaxation of the rectal smooth muscle, and an apparent increase in sweating and in the frequency of horses found masticating hay. Rectal temperature was not influenced by amitraz. The results indicated that amitraz, at the dose used, did not cause severe side effects in horses.

Treatment of adult varicella with sorivudine: a randomized, placebo-controlled trial

The antiviral and clinical efficacy of sorivudine in adults with varicella was evaluated in a double-blind, placebo-controlled randomized trial. A total of 186 patients were hospitalized for isolation and treatment within 96 h of rash onset. The diagnosis of varicella was confirmed in 184 patients with paired sera. Patients were randomly assigned to receive 10 or 40 mg of sorivudine or an identical placebo once a day for 5 days. Treatment with 40 mg of sorivudine (compared with placebo) shortened the mean time to 100% crusting from 6.6 to 5.8 days (P = .004) and reduced the mean days that new lesion formed from 3.9 to 3.1 (P = .014). Mean days of cutaneous viral shedding were reduced from 3.3 in the placebo group to 2.6 in the 40-mg sorivudine group (P = .002). The effectiveness of therapy was not affected by the duration of rash before initiation of therapy. Sorivudine is a promising new agent for the treatment of varicella-zoster virus infections.

A fragment of substance P with specific central activity: SP(1-7)

Amino-terminal fragments of substance P (SP), SP(1-7) and SP(1-8), were found to produce naloxone-reversible antinociception in the mouse similar to that produced by SP. Similar to SP, these peptides produce antinociception only within a narrow dose range. They have no activity on smooth muscle or blood pressure. These results suggest that contrary to peripheral effects of SP, which are mediated by receptors which recognize the carboxy-terminal part of the SP molecule, certain central actions of SP are mediated by receptors which recognize the amino-terminal part of the SP molecule. SP may be metabolized to this active fragment prior to its action at these receptors.

Catechol-O-methyl transferase and monoamine oxidase activities in brains of mice susceptible and resistant to audiogenic seizures

The activities of catechol-O-methyl transferase (COMT), monoamine oxidase (MAO), and a methanol forming enzyme were studied in whole brain homogenates and in livers obtained from DBA/2J, C57B1/6J, and F1 hybrid mice. DBA/2J mice are extremely susceptible to audiogenic seizures, whereas C57B1/6J mice are resistant to sound-induced convulsions. C57B1/6J mice were found to have significantly higher brain levels of COMT, while MAO activities were not different in animals of these genotypes. No methanol forming activity was detected in animals of either strain. No differences were found in hepatic activities of either COMT or MAO. Pyrogallol was shown to protect DBA/2J animals against audiogenic seizures.

Induction of neuronal functions: acetylcholine-induced acetylcholinesterase activity in mouse neuroblastoma cells

Addition of acetylcholine to growing cultures of mouse neuroblastoma cells induced a 37-fold increase in the specific activity of acetylcholinesterase (EC 3.1.1.7). Morphological changes, consisting of neurite-extensions, were also observed during the logarithmic phase of growth of cells stimulated with acetylcholine. A histochemical procedure for localization of acetylcholinesterase was used with the following results: (a) Cells differentiating by growth inhibition in serum-free medium do not stain positively for acetylcholinesterase, except when they have extended neurites, whereas all cells induced with acetylcholine, with or without neurites, stain positively for the enzyme. (b) The inverse relation between cell growth and induction of enzyme activity was demonstrated in nondividing cells at the center of a colony that do not incorporate thymidine into DNA and that stain positively for acetylcholinesterase, whereas actively dividing cells on the periphery of the colony do not stain for the enzyme. However, by addition of acetylcholine we were able to dissociate inhibition of cell growth from biochemical and morphological differentiation in mouse neuroblastoma cells.