Microsatellite evidence for obligate autogamy, but abundant genetic variation in the herbaceous monocarp Lobelia inflata (Campanulaceae).

Although high levels of self-fertilization (>85%) are not uncommon in nature, organisms reproducing entirely through selfing are extremely rare. Predominant selfers are expected to have low genetic diversity because genetic variation is distributed among rather than within lineages and is readily lost through genetic drift. We examined genetic diversity at 22 microsatellite loci in 105 individuals from a population of the semelparous herb Lobelia inflata L. and found (i) no evidence of heterozygosity through outcrossing, yet (ii) high rates of genetic polymorphism (2-4 alleles per locus). Furthermore, this genetic variation among lineages was associated with phenotypic traits (e.g. flower colour, size at first flower). Coupled with previous work characterizing the fitness consequences of reproductive timing, our results suggest that temporal genotype-by-environment interaction may maintain genetic variation and, because genetic variation occurs only among lineages, this simple system offers a unique opportunity for future tests of this mechanism.

Off-line automated sample preparation--experience in a clinical drug investigation unit.

The authors describe an evaluation of the Du Pont Prep. off-line automatic centrifugal sample processing system, used in the authors' Drug Investigation Unit over the past two years. In comparison to liquid-liquid extraction, the authors found that assay precision has generally been improved, absolute recovery was quantitative, reliability has been good and the use of the system has resulted in notable labour saving. However, the cost per test based on a seven-year amortization of capital cost shows that the system is more expensive. Assays for urinary opiates, serum tricyclic antidepressants, serum isoxicam, serum valproate, serum metoclopramide and serum pindolol are presented and the merits of the method are compared with those for manual liquid-liquid extraction procedures.

A method for the postmortem evaluation of an in situ total hip replacement.

A method was developed for the post-mortem evaluation of a total hip replacement retrieved in situ. The hip replacement had been implanted for six years. The evaluation procedure employed existing techniques in a logical sequence such that earlier tests would not compromise results from subsequent ones. These techniques included the measurement of range of motion, aspiration of the joint for analysis of debris, radionuclide arthrograms for determination of looseness of the components, gross and histological inspection of the capsule and synovial tissue, serial sectioning of the femoral component, determination of some mechanical properties of the bone and femoral stem, and scanning electron microscopy of the articulating surfaces of the prosthetic components. Positive findings in the specimen studied were: excessive wear of the articulating surface of the acetabular component, and associated polyethylene debris in the aspirate and surrounding synovial and granulation tissue.

Treatment of subacute sepsis of the hip by antibiotics and joint replacement. Criteria for diagnosis with evaluation of twenty-six cases.

Total hip replacement fixed with acrylic cement can be successful despite past or present hip infection. Recovery of the infecting organism must be vigorously pursued, either by repeated aspirations or open biopsies. Staging the reconstruction is determined by the pathogenicity of the infecting organism, gram stain, frozen section, and above all the surgeon's observations of the condition of the wound. If in doubt, treatment of infection must take precedence over the reconstruction. Adequate antibiotic coverage should begin as soon as the diagnosis is certain and the organism identified. Antibiotics should be continued postoperatively for one month intravenously, followed by 4--8 months oral therapy, though the length of oral antibiotics could be debated. A number of authors have based their diagnosis of hip infection on clinical, roentgenographic, laboratory and bacteriologic studies. However, they have not given specific guidelines for the determination of deep hip infection. The application of the criteria outlined in this paper can distinguish superficial from deep hip infection as illustrated in 40 cases with no evidence of recurrence of infection. For the present only relative guidelines may be drawn for the treatment of subacute or recently arrested sepsis of the hip. Considering some 80,000 total hip replacements done in the U.S. in the past year, a significant number of patients will require treatment of this type and appropriate programs should be established for the welfare of the patients.