Phenotypic mixing between reticuloendotheliosis virus and avian sarcoma viruses.

Coinfection of chicken embryo fibroblasts with reticuloendotheliosis virus (REV) and avian sarcoma virus leads to the formation of avian sarcoma viral pseudotypes which carry envelope determinants of REV. These pseudotypes can be neutralized by REV antiserum, have a host range which is different from that of any known avian sarcoma virus, and are unable to form foci in cells preinfected with REV. The REV stocks used in these experiments were plaque-purified. They were free of avian leukosis virus detectable in the COFAL tests, and their ability to form pseudotypes with avian sarcoma virus was neutralized with specific REV antiserum.     

Progestagen-releasing vaginal rings--an update

Marketing of an intravaginal ring that releases a progestagen at low dosage willbegin in 1985. The device is a silicone rubber toroidal ring 55.6 mm in diameter. Its active constituent is 5 mg of levonorgestrel, with an in vivo release rate of 20 mcg/day. The device is left in the vagina for 3 months, at which point a new ring is fitted. The device largely acts locally on the genital tract, altering cervical mucus so that it is relatively inpenetrable to sperm. Over 50% of cycles in device acceptors are ovulatory; 19% have inadequate luteal function and 29% are anovulatory. In a social acceptability study involving 27 ring users, all participants asserted at the 8 week follow up that the ring was the best method they had used and indicated an interest in continuing to use the device. Over 50% cited health reasons for this choice. The ring was viewed as less invasive than the IUD and more convenient than the diaphragm. The greatest criticism of the ring resulted from changed menstrual patterns; in most cases, however, it was the unexpectedness of the change rather than the change itself that concerned the user. Clinical trials have suggisted that the ring is viable in terms of its safety, efficacy, and overall acceptability. The pregnancy rate in 5500 woman-months of experinence stands at 3%, and there has been no evidence of an increased incidence of actopic pregnancy. Although 20% of women experienced expulsion of the device, only 2% discontinued use for thes reason. The continuation rate of 60% after 1 year's use compares favorably with other methods of hormonal contraception.     

Chemonucleolysis. A ten-year retrospective study

An 11.8-year median follow-up evaluation of 42 "ideal" patients who had chemonucleolysis was obtained by examination, questionnaire, and roentgenograms. The excellent and good rating of this group was 81%, as compared to the total of 135 patients previously evaluated at 42 months and showing 85.2%. No complications were noted. Disc space rewidening, after initial narrowing, was observed in eight patients and 26% of all discs injected. While all who showed rewidening had excellent results, widening was not necessary to achieve an excellent rating. Marked narrowing and sclerosis of intervertebral margins were seen in many excellent and good clinical results. Chemonucleolysis represents a viable option as definitive treatment for a herniated nucleus pulposus in carefully selected patients.     

Correction to: Factor Structure and Equivalence of Maternal Resources for Care in Bangladesh,Vietnam, and Ethiopia

Maternal and Child Health Journal - The article “Factor Structure and Equivalence of Maternal Resources for Care in Bangladesh, Vietnam, and Ethiopia”, written by Sulochana Basnet,...     

Relationship of reproductive success and median longevity to food intake, in the captive female spider Frontinella pyramitela

Two biological phenomena (prolongation of life span with dietary restriction, and life shortening with reproductive activity) have been described in several species but treated separately. For captive female bowl and doily spiders (Frontinella pyramitela), data reported by Austad were analyzed in terms of food consumed. "Reproductive success" was defined; its rate of change could be directly equated to food intake. To describe life span, the specific rate of change of median longevity was noted to be negatively proportional to the specific rate of change of food intake. Both reproductive success and changes in median longevity are coupled to food intake in these female spiders, and can be described by quantitative expressions.     

Comparing costs of monitoring glaucoma patients: hospital ophthalmologists versus community optometrists

OBJECTIVES: To compare the costs of monitoring stable glaucoma patients by community optometrists and hospital ophthalmologists. METHODS: A cost analysis was conducted alongside a randomised controlled trial which compared the accuracy and acceptability of measurement in each form of care. The viewpoints of the health service and of patients were considered. Costs were assessed using a number of different methods. Sensitivity analysis was conducted for key variables. RESULTS: The baseline analysis reflected heavily the different length of time between follow-up in the two arms of the trial (10 months (average) for hospital, 6 months for optometrists). It showed annual cost per patient for hospital ophthalmologists varied from 14.50 pounds to 59.95 pounds, and community optometrist costs varied from 68.98 pounds to 108.98 pounds. Assuming a 6-month follow-up interval for the hospital ophthalmologists, costs varied from 24.16 pounds to 99.92 pounds. CONCLUSIONS: Recommendations about the least costly form of follow-up must depend on the context in which the decision is being taken and the scale of change envisaged. If the aim is to recoup resources from hospitals in order to pay for monitoring in the community, community monitoring is unlikely to be the least costly option.     

Dynamic assessment of the electrocardiographic QT interval during citrate infusion in healthy volunteers.

OBJECTIVE--To investigate changes in the electrocardiographic QT interval during rapidly induced, sustained hypocalcaemia in healthy volunteers. DESIGN--Serial rate corrected QT measurements were made during and after a variable rate trisodium citrate infusion designed to "clamp" the whole blood ionised calcium concentration 0.20 mmol/l below baseline for 120 min. SUBJECTS--12 healthy teetotallers aged 19- 36 years who were not receiving medication known to influence calcium homoeostasis. MAIN OUTCOME MEASURES--Whole blood ionised calcium concentration and QaTc intervals (onset of the Q wave to T wave apex divided by the square root of the RR interval). RESULTS--Mean (SD) ionised calcium concentration decreased from 1.18 (0.03) mmol/l preinfusion to values close to target (0.98 mmol/l) between 10 and 120 min. The QaTc interval lengthened from a baseline of 0.309 (0.021) to a maximum 0.343 (0.024) s0.5 at 10 min before returning to a stable level from 15 to 120 min (0.334 (0.023) and 0.330 (0.023) s0.5 respectively). The change from baseline of both variables expressed as a ratio (delta QaTc/ delta [Ca2+]) was greater during rapid induction of hypocalcaemia (at 5 and 10 min) than at other times during and after the infusion (P < 0.02). CONCLUSIONS--The disproportionate prolongation of QaTc interval during prompt induction of hypocalcaemia suggests rate dependency which can be represented by a hysteresis relation between (ionised calcium, QaTc) coordinates. This finding may have clinical implications.     

Strategies to assess validity of self-reported exposures during the Persian Gulf War. Portland Environmental Hazards Research Center

Research in the area of Persian Gulf War Unexplained Illnesses (PGWUI) is heavily dependent on self-reports of exposures. The Portland Environmental Hazards Research Center (PEHRC) conducted a population-based case-control study utilizing techniques to measure the magnitude of potential error in self-reports of exposure. While it is impossible to verify most exposures in the Persian Gulf War (PGW), results of our study reveal significant overreporting of exposures that can be verified based on the time period served in the Persian Gulf. Test-retest reliability estimates indicate inconsistency in frequency and rate of self-reported exposures during the PGW. Unexplained illness in PGW veterans has received much political and scientific attention. Self-reported exposures in surveys returned preceding and following media reports on particular exposure such as nerve gas or pesticides are presented. These results are useful in the interpretation of findings related to the PGWUI and in the design of future investigations.     

Variation in dental service provision among adult migrant public-funded patients

OBJECTIVE: To examine type of care, oral health status and service patterns by country of birth and language. METHODS: A random sample of public-funded patients (n = 6, 109) was surveyed in 1995-96. RESULTS: Emergency care was highest among overseas-born patients who spoke a non-English language at home; edentulism was highest among Australian-born/English only patients; while a higher percentage of Australian-born persons were in the periodontal health category (chi 2; p < 0.05). Differences in caries experience were generally small (ANOVA; p < 0.05). Service provision varied by country of birth/language after controlling for socio-demographic characteristics, type of care, and oral health status in six service areas (logistic regression; p < 0.05). CONCLUSIONS: Service patterns may reflect behavioural and cultural factors of patients or providers operating independently of socio-demographic and oral health status variables. IMPLICATIONS: Variation and potential inequality in service patterns related to cultural factors existed within a group of disadvantaged patients.