A multicouple probe for temperature gradient measurements in biological materials

An easy-to-make, sensitive, thin, flexible, multisensor probe for in vivo tissue temperature profile measurement is described. It is essentially a multijunction thermocouple (i.e., a multicouple) of type-T composition. Enamel-insulated copper wires (38 gauge) were soldered 5 mm apart to one common uninsulated constantan wire (36 gauge) and introduced into a polyethylene tube sealed at one end. The total outside diameter of the multicouple probe is less than 1 mm, and the maximum number of junctions using the specified wire sizes is approximately 16. This design permits the instantaneous measurement of a tissue temperature profile at 5-mm intervals over a distance of approximately 8 cm. An extensive calibration for the thermal conductivity effect (k effect) along the multicouple wires by means of a limb model is presented. The results show that the temperature readings of the individual junctions are significantly affected by the k effect when a thermal gradient exists along the multicouple, as is usually the case during tissue temperature measurements. However, calibration of the multicouple for the k effect yields a measurement accuracy of +/- 0.1 degree C under a wide range of gradients. This probe can be implanted in tissues to measure thermal gradients under different physiological conditions.     

Cyclic intramuscular temperature fluctuations in the human forearm during cold-water immersion.

The purpose of the present study was to investigate the intramuscular temperature fluctuations in the human forearm immersed in water at 15 degrees C. Tissue temperature (Tt) was continuously monitored by a calibrated multicouple probe during 3 h immersion of the forearm. The probe was implanted approximately 90 mm distal from the olecranon process along the ulnar ridge. Tt was measured every 5 mm, from the longitudinal axis of the forearm (determined from computed tomography scanning) to the skin surface. Along with Tt, rectal temperature, skin temperature and heat loss of the forearm were measured during the immersions. Five of the six subjects tested showed evidence of cyclic temperature fluctuations in the forearm limited to the muscle tissue. The first increase of the muscle temperature was observed 75 (SE 6) min after the onset of the immersion, and the duration of the cycle averaged 36 (SE 3) min. The maximum increase of the muscle temperature, which ranged between 0.4 degrees C and 1.0 degrees C, was measured at the axis of the forearm, and was inversely correlated to the circumference of the subject's forearm (P less than 0.05). No corresponding increases of the skin temperature and heat loss of the forearm were observed for the complete duration of the immersion. These data support the hypothesis of a significant contribution of the muscle vessels during cold-induced vasodilatation in the forearm.     

Further studies on the relationship of adrenal and gonadal steroids in pubertal development in female rats.

Surgical adrenalectomy or the administration of aminoglutethimide, corticosterone (B), and androstenedione (delta 4) to the immature female rat had no effect on the timing of vaginal membrane opening. Dehydroepiandrosterone (DHA) and estrone (E1) significantly hastened vaginal patency. Aminoglutethimide increased pituitary LH content while FSH content was decreased. An anti-17 beta-E2 antibody increased pituitary LH content and plasma concentration suggesting enhanced synthesis and release of LH. Pituitary FSH content was unaltered while plasma FSH decreased. Aminoglutethimide increased adrenal and ovarian but not pituitary weight while the antibody had no effect. Since little DHA is present in rat plasma and adrenal and since only estrogens have any effect on the onset of puberty, it is likely that the adrenal is not directly involved in pubertal development in the female rat.     

Ultrastructural Features of the Oral Region of Amicronucleate Paramecium tetraurelia in Autogamy1

ABSTRACT Amicronucleate Paramecium tetraurelia fails to develop an oral apparatus but resorbs the pre-existing one in the sexual cycle. Previous cytological studies have revealed the presence of a shallow, oral depression with a few scattered basal bodies after autogamy or conjugation. The present ultrastructural study of the ectoplasm beneath the oral depression revealed only the presence of a disorganized filamentous reticulum and small blocks of cytopharyngeal ribbons. In addition, beneath the oral depression, a large number of discoidal vesicles were found, similar to but larger in diameter than those normally associated with the cytopharynx of vegetative cells. The oral structures found in amicronucleates in autogamy might be remnants of the pre-existing oral apparatus, but the possibility that they were newly developed was not excluded. The morphogenetic interest of these structures was discussed. It is evident that amicronucleates in autogamy do not develop an extensive oral ultrastructural organization.     

Comparing genetic variants detected in the 1000 genomes project with SNPs determined by the International HapMap Consortium

Single-nucleotide polymorphisms (SNPs) determined based on SNP arrays from the international HapMap consortium (HapMap) and the genetic variants detected in the 1000 genomes project (1KGP) can serve as two references for genomewide association studies (GWAS). We conducted comparative analyses to provide a means for assessing concerns regarding SNP array-based GWAS findings as well as for realistically bounding expectations for next generation sequencing (NGS)-based GWAS. We calculated and compared base composition, transitions to transversions ratio, minor allele frequency and heterozygous rate for SNPs from HapMap and 1KGP for the 622 common individuals. We analysed the genotype discordance between HapMap and 1KGP to assess consistency in the SNPs from the two references. In 1KGP, 90.58% of 36,817,799 SNPs detected were not measured in HapMap. More SNPs with minor allele frequencies less than 0.01 were found in 1KGP than HapMap. The two references have low discordance (generally smaller than 0.02) in genotypes of common SNPs, with most discordance from heterozygous SNPs. Our study demonstrated that SNP array-based GWAS findings were reliable and useful, although only a small portion of genetic variances were explained. NGS can detect not only common but also rare variants, supporting the expectation that NGS-based GWAS will be able to incorporate a much larger portion of genetic variance than SNP arrays-based GWAS.     

Borrelia burgdorferi infection in Ixodes ricinus from habitats in Denmark

A total of 2647 ticks of the genus Ixodes was sampled by flagging the vegetation in thirty-one sites in eastern Jutland, Denmark. All ticks were identified as Ixodes ricinus Linnaeus. A total of 317 ticks (202 nymphs and 115 adults) from three different sites were examined for the spirochaete Borrelia burgdorferi Johnson et al. by indirect fluorescent antibody staining; the frequency of infection varied from 7% to 22%. It is concluded that I. ricinus, known to be the most common tick in Denmark, is the vector largely responsible for the transmission of B. burgdorferi in this country.     

Phyllotaxis in the Oil Palm: Arrangement of Male/Female Spikelets on the Inflorescence Stalk

The geometry of spikelet arrangement along the massive maleand female inflorescences of this monoecious palm is investigatedthrough techniques of phyllotaxis measurement (Equivalent phyllotaxisindex or E.P.I. Essentially there is little apparent differencewhether E.P.I. values from male inflorescences or female areconsidered. In both sexes E.P.I. estimates vary in a curvilinearmanner along the inflorescence length, higher values being obtainedtoward the broad base. Based on this pattern one value-over-allinflorescence E.P.I. is suggested to compare bunches emanatingfrom different treatment or genetic sources. It is also shownthat over-all bunch (inflorescence) E.P.I. varies systematicallywith palm age, being low in young palms and rising to asymptoticlevels in c. 11-year-old palms. Some physiological explanationsfor this latter observation are put forward, and some possibleapplications in cultural and genetic studies are suggested.Attention is also given to describing the results in terms ofFibonacci contact parastichy systems.