The asymmetric pincer and snapper claws in the snapping shrimp differ in external morphology and musculature. The snapper is a massive claw used for displays and defense; the pincer is small and slender, used for feeding and burrowing. The snapper has only slow muscle fibers; the pincer has both slow and fast. Removal or denervation of the snapper claw induces transformation of the contralateral pincer to a snapper type of claw at the subsequent molt. A removed claw regenerates as a pincer type, as long as the innervation of the remaining claw is intact. Fast muscle fibers, found exclusively in the pincer claw, normally degenerate completely within 10 d after the moult, which transforms the pincer to a snapper. Morphological transformation of the pincer following removal of the snapper claw can occur even if the pincer claw is denervated. Denervation of the pincer, however, delays degeneration of the fast fibers, increasing the estimated half-time of muscle degeneration, for 4.4 +/- 0.2 to 19.5 +/- 0.8. d after the transforming moult. Neural influences therefore are involved both in the determination of the morphology of the claw and in the induction of degenerative changes during the remodeling of an existing claw.

Animals↗

PubMedDate not supplied

Bioassayable cholecystokinin in the brain of the goldfish, Carassius auratus.

Cholecystokinin (CCK)-gastrin peptides are shown to be present in the brain of all the species ranging from coelenterates to mammals. Differentiation between CCK and gastrin, presumed to be evolved from a common ancestral cerulein-like peptide, has been suggested to occur at the level of the amphibians. We examined the presence of bioassayable CCK, as determined by its potency to stimulate enzyme secretion from isolated rat pancreatic acini, in the brain of the goldfish Carassius auratus, a more primitive vertebrate than the amphibian. Among the various regions tested, the brain stem, telencephalon and spinal cord possess the highest levels of bioassayable CCK followed in decreasing order by gustatory lobes, optic tectum and duodenum. No detectable levels of CCK were found in the cerebellum. The observed bioactivity was not due to gastrin because: radioimmunoassay of the brain homogenates for gastrin revealed very low or nondetectable levels of gastrin; amylase release dose-response curves for standard CCK8 and the brain homogenate were identical; and proglumide, a competitive antagonist of CCK8, inhibited homogenate CCK-induced enzyme release with a parallel rightward shift in the dose-response curve. These observations provide evidence for the distinct presence of CCK in the brain of the goldfish suggesting that the differentiation of CCK as a distinct neuropeptide, from that of gastrin, occurs at the level of Osteichthyes (bony fish).

Amino Acid Sequence↗

PubMedDate not supplied

Opacification of artificial intraocular lens: an electron microscopic study.

This paper describes the usefulness of electron microscopy in the investigation of the cause of opacification of an intraocular artificial lens (IOL), which affected both the anterior and posterior surfaces of the IOL. The explanted lenses were remarkably similar and were uniformly opaque, with "reticulated" surfaces under dissecting and ordinary light microscopes. TEM showed that the surfaces of the explanted lenses were irregular, and there was a layer of electron-dense granular deposits that extended to a depth of approximately 5 microm into the lens substance. SEM showed a "cerebriform" lens surface with elevated areas alternating with depressed crevices, which corresponded nicely to the TEM appearance. Energy-dispersive x-ray analysis showed that the deposit was composed of calcium, oxygen, and phosphorus, which was later shown to be calcium hydroxyapatite by x-ray diffraction study. Electron microscopy has proven to be an essential tool in the investigation of the cause of this mysterious outbreak of opacification of the surfaces of the artificial lenses. Apart from directly visualizing the lens surfaces in a 2- and 3-dimensional manner, it also provides information on the elemental composition of the deposit. Such findings enable the clinicians and manufacturer to search for the underlying pathogenesis of the abnormal calcium hydroxyapatite crystals deposit.

Calcinosis↗

PubMedDate not supplied

Aluminum does not accumulate in teenagers and adults on prolonged parenteral nutrition containing free amino acids.

Prolonged total parenteral nutrition (TPN) with solutions containing hydrolyzed casein has been associated with aluminum accumulation in patients with bone disease. We investigated the effects of free amino acids in TPN solution on plasma, urine, and bone aluminum in six patients, five of whom had symptoms of bone disease or documented demineralization. No evidence of aluminum accumulation was found. TPN with free amino acids, containing 42 micrograms aluminum per liter or less, does not lead to aluminum loading in adolescents or adults.

Adolescent↗

PubMedDate not supplied

Survey of home nutritional support patients.

Patients receiving home parenteral nutritional services from a major corporate provider were surveyed using a written questionnaire. The survey questioned the patients about use of home parenteral nutritional services and the quality of life while receiving home parenteral therapy. Patient satisfaction with home nutritional support services, and the impact home therapy has on patient medical, financial and psychosocial status were examined. Life satisfaction measures were compared with that of end stage renal disease patients and the overall United States population. Of the 1140 patients sent the written questionnaire, 347 (30.4%) returned the survey. Half the patients had been placed on home parenteral nutrition services because of short bowel syndrome. The mean length of time respondents had been receiving home parenteral nutrition services was 35 months, reporting approximately one hospitalization per year due to complications of their home parenteral nutrition. Blood infection with catheter as focus was most frequently reported as being responsible for hospitalization. The number of hospitalizations due to complications of home parenteral nutrition therapy was positively correlated with length of time on the program. Overall, respondents were satisfied with their home nutrition services, but were less satisfied with life as a whole when compared to the overall United States population and to end stage renal disease patients.

Adolescent↗

PubMedDate not supplied

EGF-receptor and extracellular matrix changes in mouse pulmonary carcinogenesis.

Malignant Balb/c mouse lung cell clones related to alveologenic carcinoma exhibited low levels of epidermal growth factor (EGF) receptor activity compared to nonmalignant cell clones. Immunoprecipitation of cell homogenates and immunohistochemistry on urethane-induced lung tumors suggest that the absence of activity reflects decreased amounts of EGF receptor protein. Low levels of EGF receptor alone cannot cause neoplastic transformation, since a nonneoplastic cell cone, B5D3, exhibited low levels of EGF receptor despite its nontransformed phenotype. The reduced levels of EGF receptor in malignant clones have been mimicked by long-term (12 h) treatment of a nontransformed cell clone with 200 nM phorbol dibutyrate. The detection of mutated ras oncogene in the transformed cell lines, taken together with the EGF receptor findings, suggests that more than one alteration in the signal transduction pathway may be necessary for transformation in alveologenic adenoma and carcinoma cell systems. A further phenotypic feature of transformation, reduced expression of the extracellular matrix proteins fibronectin and laminin, may be mediated at the transcriptional level.

Animals↗

PubMedDate not supplied

Comparisons between active vs. passive end-range assessments in subjects exhibiting cervical range of motion asymmetries.

OBJECTIVE: To compare cervical range of motion values following active (nonpractitioner-assisted) vs. passive (practitioner-assisted) movement of the head to end range. DESIGN: Randomized, double-blind, within-subject comparisons. SETTING: Cervical Ergonomics Laboratory, Palmer College of Chiropractic-West, Sunnyvale, CA. SUBJECTS: Pain-free chiropractic college students, nearly evenly divided with respect to gender and ranging from 22-38 yr of age, were used in the study. Subjects exhibiting goniometrically determined cervical lateral-flexion or rotational passive end-range asymmetries of 10 degrees or greater were selected for experimentation. INTERVENTION: None. MAIN OUTCOME MEASURE: A goniometric (inclinometric) device was used for active and passive cervical end-range assessments. Active assessments were performed first, followed immediately by passive assessments in each subject. RESULTS: Results demonstrated that the magnitudes of end-range asymmetry detected following active assessment were only about half of those observed following passive assessments. Moreover, whereas active end-range values were about 5 degrees less than passive on the most restricted side of passive movement, active end-range values were about 10 degrees less than passive on the least restricted side of passive end range. CONCLUSIONS: These results are consistent with the notion that cortical influences mediating active movement are rather intolerant of asymmetric states involving end-range capability. This results in compensatory reductions in active movement on the side of greatest potential passive end range, thereby acting to preserve symmetry at the expense of overall range of motion. Results also suggest that measures obtained following active movement may be far more difficult to interpret than those obtained following passive assessments, particularly when information regarding possible asymmetry of end-range capability is considered to be of primary clinical and/or experimental importance.

Adult↗

PubMedDate not supplied

R-verapamil decreases anti-estrogen resistance in a breast cancer model.

Drug resistance eventually limits the effectiveness of antiestrogens in breast cancer treatment. Pharmacological reversal of this refractoriness has been attempted with R-Verapamil, a well tolerated calcium channel blocker. This drug significantly decreased the incidence of lung foci after intravenous seeding of the R3230AC rat adenocarcinoma; this effect was correlated with reduction in the expression of P-glycoprotein. The simultaneous administration of antiestrogens with a non-toxic enantiomer of Verapamil was beneficial in the tumour model investigated.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Preservation techniques for heart transplantation: comparison of hypothermic storage and hypothermic perfusion.

Preservation of the donor heart is an important and controversial subject in heart transplantation. This study compares simple hypothermic storage and hypothermic perfusion in a swine model of heart transplantation (n = 14). The donor hearts of group A (n = 7) were placed in simple hypothermic storage for 5 hours. The donor hearts of group B (n = 7) were placed onto a perfusion apparatus for 5 hours, with pressure maintained at 28 cm of H2O and a myocardial temperature of 8 to 10 degrees C. In both groups the hearts were initially protected with isosmolar potassium cardioplegic solution. The perfusate in group B contained moderate sodium, mannitol, glucose, insulin, and oxygen. The ischemic interval within both groups was 6 hours including orthotopic transplantation. Investigation was conducted at three time periods: prepreservation, postpreservation, and immediately after loading. For both groups there was nonsignificant depression of myocardial function (cardiac index, stroke index, stroke work index, ejection fraction, and wall stress) at the postpreservation period. After volume loading, for the hypothermic perfusion group there was significant improvement of myocardial function (cardiac index, p less than 0.01; stroke index, p less than 0.01) with no significant change in heart rate, systemic vascular resistance, and systolic blood pressure. There was also significant improvement in myocardial performance (p less than 0.05) for the hypothermic perfusion group after volume loading. Ultrastructural changes were minimal for both groups, and there were no major heart transplantation after 6 hours of ischemia; however, hearts retain their contractile capacity better after hypothermic perfusion than after simple hypothermic storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Single-chain, urokinase-type plasminogen activator in a tumor model linked to metastatic potential.

Single-chain urokinase-like plasminogen activators have been determined by an indirect method (after activation to urokinase by plasmin and chromogenic assay with S 2444) in the cytosol of a rat tumor model. Variants of the R 3230 AC rat mammary adenocarcinoma were studied, including a subline with increased metastatic potential established by lung colony assay. The cellular content of the UK precursor was found to be significantly higher in the metastatic variant. Plasminogen activator-mediated invasion and collagenolysis of cells with the metastatic phenotype may be regulated by the release of the precursor which lacks reactivity with inhibitors, its transient activation and subsequent inhibition of the urokinase formed.

Adenocarcinoma↗

PubMedDate not supplied

Tamoxifen therapy in unresectable adenocarcinoma of the pancreas.

Twenty-four patients with biopsy-documented unresectable ductal adenocarcinoma of the pancreas were treated with tamoxifen. Six of 15 postmenopausal female patients had documented prolonged survival, with three living greater than 2 years.

Adenocarcinoma↗