Resonator with Ultrahigh Length Stability as a Probe for Equivalence-Principle-Violating Physics.

In order to investigate the long-term dimensional stability of matter, we have operated an optical resonator fabricated from crystalline silicon at 1.5 K continuously for over one year and repeatedly compared its resonance frequency f_{res} with the frequency of a GPS-monitored hydrogen maser. After allowing for an initial settling time, over a 163-day interval we found a mean fractional drift magnitude |f_{res}^{-1}df_{res}/dt|<1.4×10^{-20}/s. The resonator frequency is determined by the physical length and the speed of light and we measure it with respect to the atomic unit of time. Thus the bound rules out, to first order, a hypothetical differential effect of the Universe's expansion on rulers and atomic clocks. We also constrain a hypothetical violation of the principle of local position invariance for resonator-based clocks and derive bounds for the strength of space-time fluctuations.

Delayed behavioural aging and altered mortality in Drosophila beta integrin mutants.

The genetic basis for aging is being intensely investigated in a variety of model systems. Much of the focus in Drosophila has been on the molecular-genetic determinants of lifespan, whereas the molecular-genetic basis for age-related functional declines has been less vigorously explored. We evaluated behavioural aging and lifespan in flies harbouring loss-of-function mutations in myospheroid, the gene that encodes betaPS, a beta integrin. Integrins are adhesion molecules that regulate a number of cellular processes and developmental events. Their role in aging, however, has received limited attention. We report here that age-related declines in locomotor activity are ameliorated and that mean lifespan is increased in myospheroid mutants. The delayed functional senescence and altered mortality in myospheroid flies are independent of changes in body size, reproduction or stress resistance. Our data indicate that functional senescence and age-dependent mortality are influenced by beta integrins in Drosophila.

Dihydrotestosterone activates sexual behavior in adult male hamsters but not in juveniles.

The effect of an androgenic metabolite of testosterone, dihydrotestosterone (DHT), on reproductive behavior and brain androgen receptor (AR) immunoreactivity was compared in juvenile and adult male Syrian hamsters. Prepubertal and adult animals were castrated and treated with 0, 500, or 1000 microg of DHT daily for 1 week and then tested for their ability to engage in mating behavior. The 1000-microg dose of DHT activated intromissions in adult but not prepubertal males. Brains were collected immediately after the behavioral test to investigate whether the lack of a behavioral response to DHT prior to puberty is associated with fewer AR-immunoreactive (AR-ir) cells in the forebrain nuclei that mediate male sexual behavior. In four of the five nuclei within the behavioral circuit that were examined, the number of AR-containing cells was similar in prepubertal and adult males treated with 1000 microg of DHT. Only in the anterior medial amygdala (MeA) was there a greater number of AR-ir cells in adults. These data indicate that (1) DHT does not activate components of male reproductive behavior prior to puberty and (2) the lack of behavioral responsiveness to DHT in prepubertal males is most likely not related to an overall reduction in ARs within the forebrain circuit that mediates mating behavior.

Prospective and retrospective analysis of colonoscopy findings in patients with a history of colorectal carcinoma in first-degree relatives.

The frequency of colorectal neoplasia was assessed by colonoscopy in 48 patients with a history of colorectal cancer in a first-degree relative. Twelve of these patients were found to have polyps in the colon, including 1 who had invasive cancer. Patients with multiple first-degree relatives who have a history of colorectal cancer were found to be at increased risk, 56% having colonoscopic findings positive for polyps. Of the 12 patients with positive colonoscopic findings, 5 (42%) had multiple lesions. These findings are similar to those reported in recent pedigree studies and further support a genetic basis for common colorectal cancer. First-degree relatives of patients with colorectal cancer should be considered a high-risk group for colorectal neoplasia. Screening with colonoscopy is recommended.

Heredity and colorectal cancer. A prospective, community-based, endoscopic study.

The frequency of colorectal neoplasia was assessed through colonoscopy in 114 patients with a family history of colorectal cancer. In over 90 percent of patients, a first-degree relative was affected. Twenty-one percent of patients who were studied endoscopically were positive for neoplastic disease, including two invasive cancers. Twenty-eight percent of patients had adenomas beyond the splenic flexure. Multiple primary relatives further increased risk with 36 percent positive for neoplasia. Neoplasia was common in young patients, with 25 percent under the age of 40 years positive for adenomas. These findings are identical to recent pedigree studies and further support a genetic basis for common colorectal cancers. First-degree relatives of patients with colorectal cancer should be considered at high-risk for colorectal neoplasia. Screening and surveillance with colonoscopy is recommended.

The osteoclast-type giant cell tumor of the pancreas.

We present a case report of osteoclast-type giant cell tumor of the pancreas and review the literature concerning this rare neoplasm, the histogenesis of which is uncertain. Electron microscopic features have suggested stromal, histiocytic, and epithelial origins to different investigators. Analysis of the present case supports and epithelial origin, with positive immunocytochemical staining for carcinoembryonic antigen and for low molecular weight keratin in the mononuclear and in some osteoclastlike giant cells. These tumor cells did not stain for mesenchymal markers (lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, S100 protein). Zymogen granules, desmosomes, and zonulae occludentes were identified ultrastructurally and further support an epithelial derivation.

Hemoccult test as a routine screening procedure for colorectal disease in the private clinic setting.

Increased attention is being focused on the earlier detection of malignant and premalignant colorectal lesions in an attempt to increase the survival rate of patients with these diseases. This study evaluates the use of the Hemoccult test as a screening procedure in a private clinic. A protocol for its implementation is presented. Of the 631 patients entered into the study, 514 (81.5%) returned completed slides. In 14 (2.7%) of these 514 patients, the slides gave positive results, and 10 of the 14 patients underwent thorough investigation. No malignant tumours were found as a result of the test. Six (1.2%) of the 514 patients had one or more benign polyps.

The anterior interosseous nerve syndrome.

A review of the literature pertaining to the anterior interosseous nerve (AIN) syndrome revealed that the diagnostic criteria for this syndrome need to be defined. The authors describe the etiology of the AIN syndrome and use two cases of their own and 52 cases reported in the English literature to draw up a definition of the diagnostic criteria. The recommended criteria are: (a) demonstrable weakness of muscles innervated by the anterior interosseous nerve; (b) electromyographic findings of marked denervation potentials and decreased or absent voluntary motor unit potentials of these muscles; (c) operative evidence of entrapment of, or injury to, the anterior interosseous nerve; and (d) improved power in the muscles and reversal of the electromyographic changes on follow-up after operation.