Comparative analyses within Gyrodactylus (Platyhelminthes: Monogenea) mitochondrial genomes and conserved polymerase chain reaction primers for gyrodactylid mitochondrial DNA.

In this study, we describe the complete mitochondrial genomes of Gyrodactylus brachymystacis and Gyrodactylus parvae infecting rainbow trout (Oncorhynchus mykiss) and the invasive topmouth gudgeon (Pseudorasbora parva), respectively. The two circular genomes have a common genome organization found in other Gyrodactylus species. Comparative analyses of mitochondrial genomes from six Gyrodactylus species were carried out to determine base composition, codon usage, transfer RNA and ribosomal RNA genes, major non-coding regions, and nucleotide diversity within the genus. We also provide the first universal models of the secondary structures of rrnS and rrnL for this group thereby promoting utilization of these genetic markers. Universal primers provided herein can be used to obtain more mitochondrial information for pathogen identification and may reveal different levels of molecular phylogenetic inferences for this lineage.

Surface waves and crustal structure on Mars.

We detected surface waves from two meteorite impacts on Mars. By measuring group velocity dispersion along the impact-lander path, we obtained a direct constraint on crustal structure away from the InSight lander. The crust north of the equatorial dichotomy had a shear wave velocity of approximately 3.2 kilometers per second in the 5- to 30-kilometer depth range, with little depth variation. This implies a higher crustal density than inferred beneath the lander, suggesting either compositional differences or reduced porosity in the volcanic areas traversed by the surface waves. The lower velocities and the crustal layering observed beneath the landing site down to a 10-kilometer depth are not a global feature. Structural variations revealed by surface waves hold implications for models of the formation and thickness of the martian crust.

African hot spot volcanism: small-scale convection in the upper mantle beneath cratons.

Numerical models demonstrate that small-scale convection develops in the upper mantle beneath the transition of thick cratonic lithosphere and thin oceanic lithosphere. These models explain the location and geochemical characteristics of intraplate volcanos on the African and South American plates. They also explain the presence of relatively high seismic shear wave velocities (cold downwellings) in the mantle transition zone beneath the western margin of African cratons and the eastern margin of South American cratons. Small-scale, edge-driven convection is an alternative to plumes for explaining intraplate African and South American hot spot volcanism, and small-scale convection is consistent with mantle downwellings beneath the African and South American lithosphere.

Dawn arrives at Ceres: Exploration of a small, volatile-rich world.

On 6 March 2015, Dawn arrived at Ceres to find a dark, desiccated surface punctuated by small, bright areas. Parts of Ceres' surface are heavily cratered, but the largest expected craters are absent. Ceres appears gravitationally relaxed at only the longest wavelengths, implying a mechanically strong lithosphere with a weaker deep interior. Ceres' dry exterior displays hydroxylated silicates, including ammoniated clays of endogenous origin. The possibility of abundant volatiles at depth is supported by geomorphologic features such as flat crater floors with pits, lobate flows of materials, and a singular mountain that appears to be an extrusive cryovolcanic dome. On one occasion, Ceres temporarily interacted with the solar wind, producing a bow shock accelerating electrons to energies of tens of kilovolts.

Bimodality electrophysiologic evaluation of brainstem in sleep apnea syndrome.

Previous electrophysiologic studies in the sleep apnea syndrome (SAS) have used only a single modality (brainstem auditory evoked responses [BAERs]) and yielded conflicting, inconsistent, and inconclusive results. We utilized both BAERs and somatosensory evoked responses in 12 patients with SAS and found normal central conduction times in all patients. These data argue against a significant structural alteration in both rostral and caudal brainstem, insofar as the auditory and somatosensory pathways are concerned, in patients with SAS.

Comparison of testing saliva and serum for detection of antibody to human immunodeficiency virus in Jamaica, West Indies.

BACKGROUND: In Jamaica the reported incidence of AIDS increased from 0.1/100000 in 1985 to 20.2/100000 in 1995. Here there is great reluctance to have voluntary blood testing and, indeed, any blood testing. Since only enzyme-linked immunoassay (EIA) was available for screening serum HIV-1 and 2 antibody, it was considered that a non-invasive saliva screening EIA could be an advantageous alternative. OBJECTIVE: this study was designed to evaluate the OraScreen HIV Rapid Test, a new, simple saliva screening EIA for anti-HIV-1&2 and to compare its sensitivity and specificity with a standard serum anti-HIV screening EIA in current use in Jamaica. STUDY DESIGN: specificity and sensitivity of HIV antibody assays were compared in matched serum and saliva samples obtained from 257 volunteers from a family planning clinic and from visa applicants, representing a low risk population (Group I), and from 52 volunteers known to be HIV infected (Group II). RESULTS: in Group I, 257 volunteers of unknown HIV status, one was positive for anti-HIV-1 in both serum and saliva. One other was seropositive but negative on saliva testing; confirmatory Western Blot (WB) testing on this serum was negative and this subject was tabulated as blood HIV negative. Fifty-one of the known seropositive volunteers (Group II) were saliva antibody positive. One saliva sample was inadequate and this individual was excluded from the study. Serum samples from three others in Group II were grossly haemolysed but their saliva samples were antibody positive. CONCLUSION: With the exclusion of one subject whose saliva sample was inadequate, the OraScreen HIV Rapid Test showed 100% specificity identifying 256/256 HIV antibody negative individuals, and 100% sensitivity by identifying 52/52 infected individuals as HIV antibody positive.

Epidemiological investigation for arboviruses in Jamaica, West Indies.

Arbovirus investigation in Jamaica was undertaken between 1960 and 1975. Serological studies showed that antibodies to dengue type virus and St. Louis encephalitis virus (SLE) were prevalent throughout the island for several years. In urban communities, the incidence of dengue antibody was higher than for SLE; however, in children under 10 years of age antibody to both viruses was rarely present. In rural areas, SLE was prevalent in adults and children. This virus was isolated fom Culex nigripalpus (mosquitoes) and from a nestling Mockingbird, Mimus polyglottos, in the same rural area. Dengue type 3 and type 4 were isolated from the sera of patients in an urban area, during two epidemic periods, 1963 and 1968. No other group B arbovirus was encountered on the island. Group A arbovirus was virtually absent prior to the eastern equine encephalomyelitis outbreak of 1962. That virus was isolated from brain tissue of humans and equines. Two strains of Cache Valley virus from mosquitoes, Anopheles grabhami, one strain from Aedes taeniorhynchus, and a strain of Wad Medani virus from a tick, Amblyomma cajenense, were also isolated.

Laboratory investigations on rotavirus in infantile gastroenteritis in Jamaica.

Between March 1982 and March 1983 rotaviruses were detected in faecal specimens from 193 (19%) of 1020 Jamaican children under 5 years old with acute gastroenteritis. The excretion of rotaviruses in a control group of non-diarrhoeal children was only 1.4%. Rotaviruses were detected more frequently in the cooler months of the year; the prevalence ranged from 1.7% in August to 46% in January. In a comparison of the ELISA technique and electron microscopy for investigating rotavirus infections, the ELISA was demonstrated to be more sensitive especially for weakly positive cases. Because of its relative simplicity, low cost and rapidity the ELISA appears to be more suitable for use in developing countries.

A radiographic technique for measuring the powder packing density in the cavities of trabecular bone.

An X-ray technique has been developed to enable reproducible and quantitative data to be obtained from radiographs taken by a diagnostic X-ray machine. Careful attention has been paid to the alignment of the specimen and the diagnostic tube and to operating conditions. The choice of X-ray spectrum is described together with the experimental geometry used to minimize the scattered radiation incident on the film. The resultant scattered radiation intensity achieved is about 4% of the unattenuated direct radiation. Careful calibration procedures using objects the same size as the unknown specimen are necessary to avoid the need for complicated corrections for the resulting variation in scatter across the film. The LiF powder packing density is determined as 1-32 g cm-2 with a standard error of 0-52%. Values of projected bone thickness as a function of position in the bone are given. The average percentage of bone in the trabecular specimen is determined as 12-7 +/- 0-5, which is in close agreement with measurements of the same parameter determined from an optical scanning technique. The relationship between average packing density or rho y and the percentage of bone at different positions in the specimen packing density increase in percentage of bone, as would be expected.

Experimental surface or volume deposition of radionuclides in post-mortem specimens of trabecular bone.

Techniques are described that have been developed to contaminate post-mortem specimens of human trabecular bone uniformly and artificially with three different radionuclides, 14C, 45Ca and 32P, so as to produce either a uniform volume deposition of radionuclide through the bone matrix or an 'infinitely' thin layer of radionuclide on the trabecular surfaces. Uniform volume depositions of 45C and 32P were produced by neutron activation and the 14C volume distribution was successfully achieved by rehydrating the bone matrix with 14C-labelled urea solution. Surface depositions of isotope were attempted by introducing a radionuclide into solution. Surface depositions of isotope were attempted by introducing a radionuclide into solution which was in equilibrium with trabecular bone and depositions approximating to an 'infinitely' thin layer of isotope were achieved for 32P and 14C using adenosine triphosphate-labelled molecules. Ionic calcium penetrates the bone matrix very rapidly and the best 45Ca surface deposition that could be produced penetrated the trabecular surface to an average depth of about 10 micrometer. The uniformity of deposition was analysed by autoradiography and the thickness of the 'surface' layer of radionuclide was estimated using microdensitometer scans across selected strands of the autoradiograph and comparing the film density profiles thus produced with calculations.

Photoelectron enhancement of the absorbed dose from X rays to human bone marrow: experimental and theoretical studies.

A technique is described by which lithium fluoride powder is introduced into the marrow cavities in specimens of human trabecular bone to determine the excess photoelectron dose to marrow, when bone is irradiated by X rays of energies between 20 keV and 140 keV. Three specimens of trabecular bone, containing respectively 10, 15 and 25% bone by volume, were investigated and the results compared with those derived on the basis of earlier calculations for mono-energetic electrons by Whitwell. Reasonable agreement was found between the experimental and theoretical results, although there was some indication that scatter influenced the practical measurements at the higher photon energies. Theoretical calculations are then used to derive photoelectron dose enhancements for complete bones from the measured results on the bone specimens, and mean enhancements of the marrow dose for the whole human skeleton are calculated for subjects aged 44, 9 and 1.7 years.

Measurements of endosteal surface areas in human long bones: relationship to sites of occurrence of osteosarcoma.

Using techniques of bone scanning and ashing, the areas of the endosteal surfaces in cortical and trabecular bone have been determined for the proximal, mid and distal thirds of each of the six long bones of an adult human subject. The relative frequency of occurrence of bone sarcomas, scored as to site, has been analysed in relation to these measured areas. Data on tumour occurrence have been drawn from three sources: radium-case data from Rowland and Keane (33 cases), naturally-occurring cases from series by Sissons (139 cases) and by Dahlin (473 cases). A strong correlation is demonstrated between tumour frequency and trabecular area, but correlation with cortical area is poor. By comparing the tumour frequency in the mid thirds of the bones with the total recorded it has been possible to show that the probability of tumour occurrence per unit area of cortical bone, relative to that of trabecular bone, is 0.16 +/- 0.06. Analysis of the available dose data for the radium cases shows that in this instance dose has not contributed to the observed correlations. The results lend support to the thesis that tumour occurrence depends on surface area, i.e. on the number of cells at risk.

The absorbed dose to bone marrow in the treatment of polycythaemia by 32P.

This paper reports the determination of absorbed dose to bone marrow in the treatment of polycythaemia by 32P, based on the measurement of activities in bone and marrow biopsies taken at various times from 1 to 27 days after injection of the radionuclide. Activities were measured in the cortex, trabeculation and marrow of biopsies taken from the iliac crest, and slso in sternal marrow. The biological half-life of 32P in marrow from the iliac crest was found to be nine days; that derived for sternal marrow was lower, but the difference was not statistically significant; the value for trabecular bone was 27 days. The biological half life for 32P in the body, as measured by whole-body counting, was 39 days. Calculations of the dose-rate to trabecular marrow have been made by a method based on that of Whitwell and Spiers (1971), but modified to allow for the presence of32P in the marrow as well as in trabecular bone. The dose-rates follow a single exponetial decay with a half-life of 6.7 days. The intergrated dose including that during the first day is 24 rad per mCi injected.

Symptomatic and asymptomatic chlamydial non-gonococcal urethritis in Jamaica: the potential for HIV transmission.

To determine the contribution of Chlamydia trachomatis to non-gonococcal urethritis (NGU) in men attending sexually transmitted disease (STD) clinics in Jamaica we studied men with NGU (n=339), and control groups including asymptomatic men who were STD contacts (n=61), asymptomatic men who were not STD contacts (n=32) and men with gonococcal urethritis (GU) (n=61). Urethral specimens were examined for C. trachomatis and Neisseria gonorrhoeae. Serological tests for syphilis (STS) and HIV-1 infection were also performed. C. trachomatis accounted for 63% of cases of NGU but high prevalences were also found in asymptomatic STD contacts (59%), asymptomatic STD non-contacts (78%) and men with GU (48%). The prevalence of C. trachomatis in men with GU differed significantly from that in men with NGU and asymptomatic STD non-contacts (P<0.05). C. trachomatis infection in men with NGU was associated with multiple sex partners (71% vs 58%; chi2=4.78; odds ratio (OR)=1.76; P<0.05) and previous history of gonococcal infection (83% vs 42%; chi2=59.8; OR=6.8; P<0.0001). Concomitant infection with HIV-1 occurred in 5.2% of cases of NGU and 50% and 90%, respectively, of the HIV-positive men had chlamydia or reactive STS. As a cost effective strategy in the control of STD and HIV we recommend presumptive treatment for C. trachomatis in men seeking STD treatment in Jamaica.

An assessment of the variability of early scalp-components of the somatosensory evoked response in uncomplicated, unshunted carotid endarterectomy.

Although many publications deal with the usefulness of the SER in CEAs, the criteria of calling a SER abnormal during a CEA are largely arbitrary. One way to define the limits of normalcy for SERs during the CEA will be to analyze the SER tracings obtained during unshunted and uncomplicated (intra- and postoperative) CEAs. In 23 such CEAs (10 right, 13 left; clamptime 10-23 mins.), data analysis at the ipsilateral parietal electrode, on stimulation of the contralateral median nerve (square pulse -5.1/sec, 10-30 V, 200 microseconds; bandpass-30-3000 Hz trials-500 stimuli), revealed that (1) latency fluctuations of the N20 (21.4 msec) were narrowest, being less than 1.5 msec different during and after clamping compared to the preclamp latency in all 23 CEAs, whereas those of P25 (27.4 msec) and N35 (38.5 msec) were greater than 2.0 msec different from the preclamp latency in 3 and 8 CEAs respectively, and (2) the amplitudes of N20, P25 and N35 measured from the preceding peak of opposite polarity, fell to less than 75% of the preclamp value on 3, 4 and 7 CEAs respectively. It is concluded that N20 was the most stable of the first three short-latency components in the SER and should perhaps be most relied upon to predict abnormality of the SER during CEAs.

Electrophysiologic validation of two categories of dementias--cortical and subcortical.

Recently, the dementias have been classified into 2 categories-Cortical (CD) and Subcortical (SD). Some studies have questioned this classification. We attempted to validate the classification on electrophysiologic grounds. Fourteen of 15 patients with SD had relatively normal EEGs as compared to only 3 of 15 patients with CD, matched for age, sex and severity of dementia (p greater than 0.01). SER test results were often abnormal in the SD group but always normal in CD patients. These preliminary data appear to validate the classification of dementias into SD and CD categories.

Preventing morphological disturbances in burn-scarred children wearing compressive face garments.

Continuous external compression in the form of elasticized garments is a well-accepted and substantiated form of management for postburn hypertrophic scarring. Children who have sustained deep partial thickness and/or full skin thickness burns to the face and head are frequently prescribed elasticized compressive face garments in the post-acute stage of their recovery. Recurrent concerns expressed by parents prompted investigation into the frequency of sleep disturbances, such as snoring subsequent to the application of face garments, and the possibility of changes to the developing dentition. This preliminary study utilized a single case design to demonstrate the effectiveness of a bimaxillary mouthguard in circumventing such problems.

The role of chickens in the epidemiology of eastern equine encephalomyelitis virus in Jamaica.

Since 1962, when Jamaica experienced its first and only outbreak of eastern equine encephalomyelitis (EEE), surveillance for the causative virus has been in progress. Wild birds, rodents, mosquitoes, sandflies and sentinels (domestic chickens, guinea pigs, mice and hamsters) have been constantly examined for EEE virus and serological conversion. In essence, only negative results have been obtained. Since June 1976, domestic chickens have been investigated as a possible reservoir and several have been found to have haemagglutinating antibodies, with titres ranging from 1:10 to 1:160. These titres fell rapidly, eg, from 1:160 to 1:10 within 60 days. These results incriminate the domestic fowl as a major reservoir for the virus, and suggest that the life of immunoglobulins against EEE is short in birds. Thus, the large number of negative serological tests found in previous investigations might be misleading since positive sera might have been missed between intervals of capture and recapture of the birds. The results indicate that investigators could usefully modify their procedure by bleeding wild birds as early as one to two weeks after initial capture. The importance and duration of the dominant avian anti-EEE virus immunoglobulins should be investigated.

An outbreak of influenza in Jamaica (1986).

An outbreak of febrile illness at the Police Training Academy in St. Catherine, Jamaica in October, 1986 is described. Influenza A similar to type A/Taiwan/86 (H1N1) was confirmed serologically in 33 cases, and Influenza B similar to type B/Ann Arbor/86 in 1 case. Clinical findings included upper respiratory symptoms (97%) headache (74%), fever (68%), joint pains (39%) and retro-orbital pain (26%). The role of vaccination and chemoprophylaxis in the prevention of influenza is discussed, and the importance of surveillance is stressed.

Chlamydial infections in selected populations in Jamaica.

The importance of Chlamydia trachomatis as a cause of genital tract infection in Caribbean countries is largely unknown. Two hundred and sixteen cervical and urethral specimens were collected from patients with cervicitis and urethritis attending a Sexually Transmitted Diseases (STD) Clinic, a Gynaecology Clinic and a Family Planning Clinic in Kingston. Specimens were tested for chlamydiae by direct immunofluorescence and cell culture methods. They were also investigated for N. gonorrhoeae infections. Seventy-two of 138 patients (52.2%) at the STD Clinic were positive for chlamydiae; 28 of 50 (56.0%) from the Gynaecology Clinic and 11 of 28 (39.3%) from the Family Planning Clinic were positive. The prevalence of C. trachomatis (52.3%) was higher than that of N. gonorrhoeae (11.1%) in all groups. The results indicate that C. trachomatis is a common cause of genital tract infections in Jamaica.