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PubMed1988

A lateral line analogue in cephalopods: water waves generate microphonic potentials in the epidermal head lines of Sepia and Lolliguncula.

Many cephalopods have lines of ciliated cells on their head and arms. In the cuttlefish Sepia and the squid Lolliguncula, electrophysiological recordings clearly identify these epidermal lines as an invertebrate analogue to the mechanoreceptive lateral lines of fish and aquatic amphibians and thus as another example of convergent evolution between a sophisticated cephalopod and vertebrate sensory system. Stimulation of the epidermal lines with local water displacements, generated by a vibrating sphere, causes receptor potentials that have many features known from lateral line microphonic potentials. The minimal threshold of the head lines is 0.2 micron peak-to-peak water displacement (calculated at the skin surface) at 75-100 Hz.

Action Potentials↗
PubMed1995

Reduced in vivo local recurrence with contact neodymium: Yttrium-Aluminium-Garnet (Nd:YAG) laser scalpels.

BACKGROUND AND OBJECTIVE: Local recurrence after surgical resection for breast cancer is a significant problem and is often not controlled by radiation or chemotherapy treatments. Local recurrence is thought to be, at least in part, due to residual disease, and/or due to the contamination of the surgical field during resection. STUDY DESIGN MATERIALS AND METHODS: To address this later concern, we defined a model system using the mouse mammary cell line, EMT6. Using this model system, we have directly compared the rate of local recurrence of two different surgical approaches. One approach employed the use of traditional surgical instruments, and the other used a comparatively new contact Nd:YAG laser system. Tumor-bearing animals (242) were randomized into three groups. One group consisted of 50 animals that were not treated; 103 animals were randomized into a treatment group that received surgical resection using traditional instruments; 89 animals were resected using the contact laser system. In both surgical procedures, an intentional incision was made through the tumor and then through an uninvolved portion of the surgical field in an attempt to "seed" the incision using the contaminated surgical instrument. RESULTS: Twenty-one of the 103 scalpel-treated animals had local recurrence; only seven of the 89 laser-treated animal had local recurrence. The untreated group died of disease within 8 weeks. In the treatment groups, recurrences were palpable within 1 week. At the time of death for all groups, no metastatic lesions were noted. CONCLUSION: These findings support the conclusions that the EMT6 cell line is a useful model to study local recurrence and that contact laser surgery provides about a 50% improvement in the control of local disease in vivo (P < 0.05).

Aluminum Silicates↗
PubMed1995

On-line monitoring of ethanol, acetaldehyde and glycerol during industrial fermentations with Saccharomyces cerevisiae.

Industrial fermentations carried out in a 500-l bioreactor were monitored on-line by a prototype of a split-flow modified thermal biosensor. Acetaldehyde and glycerol in the extracellular broth were monitored over the first 48 h of fed-batch fermentations. The aim was to determine the usefulness of these secondary metabolites for on-line monitoring and control. When fermentation of the 13-16 g/l batch sugar was monitored, using immobilised aldehyde dehydrogenase, the acetaldehyde reached a peak value of 0.3 g/l. With immobilised alcohol oxidase a much larger peak of 3.5 g/l ethanol was seen immediately after the acetaldehyde peak. When glycerokinase was used a delayed peak of 1 g/l glycerol was monitored. Of the three metabolites monitored, the ethanol proved the most valuable indicator of suitable timing for the start of the feeding phase and later for controlling and preventing overfeed using the on-line biosensor system.

Acetaldehyde↗
PubMed1975

Ultrastructural and pharmacological studies on the afferent synapse of lateral-line sensory cells of the African clawed toad, Xenopus laevis.

Lateral-line sensory cells of Xenopus show considerable similarity to central nervous system synapses in their responses to the zinc iodide-osmium tetroxide, and bismuth-iodide cytochemical staining techniques. Both reserpine and FLA-63 cause a reduction in the diameter and electron density of the synaptic bars, and a dramatic loss of synaptic vesicles surrounding the bars. Aminooxy acetic acid and 3-mercaptopropionic acid cause no significant changes in the sensory-cell afferent synaptic apparatus. The results are discussed in the light of the known effects of the drugs. It is concluded that a monoamine rather than an amino acid may act as the afferent transmitter.

Aminooxyacetic Acid↗
PubMed1980

The synthesis and distribution of desmin and vimentin during myogenesis in vitro.

Electrophoretic and autoradiographic analyses of the incorporation of 35S--methionine into newly synthesized proteins during myogenesis reveal that presumptive chicken myoblasts synthesize primarily one intermediate filament protein: vimentin. Desmin synthesis is initiated at the onset of fusion. Synthesis rates of both filament subunits increase during the first three days in culture, relative to the total protein synthesis rate. The observed increase in the rate of desmin synthesis (at least 10 fold) is significantly greater than that observed for vimentin, and is responsible for a net increase in the cellular desmin content relative to vimentin. Both filament subunits continue to be synthesized through at least 20 days in culture. Immunofluorescent staining using desmin- and vimentin-specific antisera supports the conclusion that desmin is synthesized only in fusing or multinucleate cells. These results indicate that the synthesis of the two filament subunits is not coordinately regulated during myogenesis. The distributions of desmin and vimentin in multinucleate chicken myotubes are indistinguishable, as determined by double immunofluorescence techniques. In early myotubes, both proteins are found in an intricate network of free cytoplasmic filaments. Later in myogenesis, several days after the appearance of alpha--actinin-containing Z line striations, both filament proteins become associated with the Z lines of newly assembled myofibrils, with a corresponding decrease in the number of cytoplasmic filaments. This transition corresponds to the time when the alpha--actinin-containing Z lines become aligned laterally. These data suggest that the two intermediate filament systems, desmin and vimentin, have an important role in the lateral organization and registration of myofibrils and that the synthesis of desmin and assembly of desmin-containing intermediate filaments during myogenesis is directly related to these functions. These results also indicate that the Z disc is assembled in at least two distinct steps during myogenesis.

Actinin↗
PubMed1998

Diencephalic and mesencephalic projections to rhombencephalic reticular nuclei in lampreys.

Behavioral studies in lampreys of the northern genera, Ichthyomyzon, reveal that sensory inputs initiate and modulate locomotion by activation of reticulospinal (RS) neurones, which constitute the primary descending system involved in motor activity. The interneurones relaying afferent vestibular, trigeminal, lateral line, cutaneous and proprioceptive inputs are localized in the rhombencephalic region of the lamprey brainstem, unlike the visual inputs that are relayed in the mesencephalic region. The knowledge of diencephalic-mesencephalic cell distributions that project to the RS neurones is limited. They were isolated by iontophoretically injecting cobalt-lysine in vitro into the middle (MRRN) and posterior (PRRN) rhombencephalic reticular nuclei of Petromyzon marinus and Ichthyomyzon unicuspis, Fourteen of 31 injections were successful (MRRN, 7; PRRN, 7). Cell groups were labeled ipsilateral to the injection site in the thalamus (corpi geniculati; pars dorsalis thalami lateralis and medialis; nucleus (n.) subhabenularis lateralis), in the epithalamus (n. commissura posteriori) and in the pretectum. Cell groups were labeled bilaterally within the dorsal region along the diencephalic-mesencephalic border (caudal pretectum and rostral tectum opticum), in tectum opticum, torus semicircularis, and tegmentum mesencephali. There were more backfilled cells from MRRN injections (538-6466 cells) than from PRRN injections (53-553 cells) (MW Rank Sum, p < 0.001). The cell bodies were less than 40 microns long ipsilateral to the injection site, and longer contralaterally. Those greater than 50 microns were backfilled from PRRN injections. The location and organization of the cell groups identified is comparable to that of other vertebrates.

Animals↗
PubMed1997

Expression of a Cu,Zn superoxide dismutase typical of familial amyotrophic lateral sclerosis induces mitochondrial alteration and increase of cytosolic Ca2+ concentration in transfected neuroblastoma SH-SY5Y cells.

We have set up a model system for familial amyotrophic lateral sclerosis (FALS) by transfecting human neuroblastoma cell line SH-SY5Y with plasmids directing constitutive expression of either wild-type human Cu,Zn superoxide dismutase (Cu,ZnSOD) or a mutant of this enzyme (G93A) associated with FALS. We have tested mitochondrial function and determined cytosolic Ca2+ concentration in control cells (untransfected) and in cells expressing either wild-type Cu,ZnSOD or G93A. We report that G93A induces a significant loss of mitochondrial membrane potential, an increased sensitivity toward valinomycin and a parallel increase in cytosolic Ca2+ concentration. The above phenomena are not related to total Cu,ZnSOD content and activity in the cell.

Amyotrophic Lateral Sclerosis↗
PubMed1989

Pharmacokinetics of cefsulodin in rat cerebrospinal fluid during experimental Pseudomonas aeruginosa meningitis.

Experimental meningitis was induced in rats with Pseudomonas aeruginosa. Bacteria were inoculated in the second ventricle. Twenty hours later cefsulodin penetration was studied in CSF by on-line cannula system which permitted sampling of CSF in the third ventricle. Comparison with healthy animals indicated breakdown of the blood-CSF barrier and high concentrations of cefsulodin were found in CSF.

Animals↗
PubMed2002

[Substance P as a factor enhancing resistance of the surfactant lung system to chronic immobilization stress].

In chronic experiments on non-line white rats the influence of system (intraperitoneal) and central (into the lateral brain ventricle) administration of substance P on lung surfactant system was studied in stressed and non-stressed animals. A single injection of substance P limited pulmonary surfactant activity disorders in immobilisation stress. Stress-induced increase of phospholipids level in broncho-alveolar lavage fluid remained the same in intracerebroventricular administration and was partly reduced in intraperitoneal one. In intact rats, a single injection of peptide was accompanied by alveolar phospholipids accumulation. In rabbits, multiple intracerebroventricular injections of substance P enhanced the opposite effect.

Animals↗
PubMed2003

Tyrosinase expression during neuroblast divisions affects later pathfinding by retinal ganglion cells.

Occulocutaneous albinism is caused by mutations in the gene encoding the enzyme tyrosinase. Individuals with this disorder are predisposed to visual system deficits. We determined the critical period during development when tyrosinase expression is essential for the appropriate pathfinding of ganglion cell axons from the retina to the dorsal lateral geniculate nucleus. We used a line of mice with a Tyrosinase transgene, the expression of which is regulatable with the lac operator-repressor system, to restrict tyrosinase activity to discrete periods of embryogenesis. When tyrosinase was expressed throughout the period of neuroblast divisions that produce the ipsilaterally projecting ganglion cells, axonal projections innervated the same volume of the ipsilateral dorsal lateral geniculate nucleus of the thalamus as in normal mice. If tyrosinase expression ceased before the end of neuroblast divisions, or was not initiated until after they had begun, the degree of ipsilateral innervation was smaller, as in albino mice. Tyrosinase expression was not required during the entire period of pathfinding itself or during final maturation of the retinogeniculate pathway. Thus, tyrosinase appears to set up a signal early in visual system development that determines the pathway taken later by ganglion cell axons.

Animals↗
PubMed2002

Brainstem lateral line responses to sinusoidal wave stimuli in still and running water.

The fish lateral line consists of superficial and canal neuromasts. In still water, afferent fibers from both types of neuromast respond equally well to a sinusoidally vibrating sphere. In running water, responses to a vibrating sphere of fibers innervating superficial neuromasts are masked. In contrast, responses of fibers innervating canal neuromasts are barely altered. It is not known whether this functional subdivision of the peripheral lateral line is maintained in the brain. We studied the effect of running water on the responses to a 50 Hz vibrating sphere of single units in the medial octavolateralis nucleus (MON) in goldfish Carassius auratus. The MON is the first site of central processing of lateral line information. Three types of units were distinguished. Type I units (N=27) were flow-sensitive; their ongoing discharge rates either increased or decreased in running water, and as a consequence, responses of these units to the vibrating sphere were masked in running water. Type II units (N=7) were not flow-sensitive; their ongoing discharge rates were comparable in still and running water, so their responses to the vibrating sphere were not masked in running water. Type III units (N=7) were also not flow-sensitive, but their responses to the vibrating sphere were nevertheless masked in running water. Although interactions between the superficial and canal neuromast system cannot be ruled out, our data indicate that the functional subdivision of the lateral line periphery is maintained to a large degree at the level of the medial octavolateralis nucleus.

Animals↗
PubMed2005

Comparative anatomy of the electrosensory lateral line lobe of mormyrids: the mystery of the missing map in the genus Stomatorhinus (family: Mormyridae).

Fish in the family Mormyridae produce weak electric organ discharges that are used in orientation and communication. The peripheral and central anatomy of the electrosensory system has been well studied in the species Gnathonemus petersii, but comparative studies in other species are scarce. Here we report on one genus of mormyrid that displays a remarkable change in the electrosensory lateral line lobe (ELL), the hypertrophied rhombencephalic structure that receives primary electroreceptor input. Although all other mormyrids studied have three distinct zones on each side of the ELL, fish of the genus Stomatorhinus exhibit only two. Therefore, the two-zone ELL is a unique derived characteristic shared by Stomatorhinus. We examined the cutaneous electroreceptors that project to the ELL in Stomatorhinus. All three types of electroreceptors previously described for G. petersii were present, but there was a significant change in one type, the mormyromast. Both mormyromast sensory cell types (A- and B-cells) are present, but the B-cell is not innervated in Stomatorhinus. We conclude that, although all cutaneous sensory cells are present, the missing B-cell afferents account for the loss of the dorsolateral zone of the ELL, and therefore the loss of an entire sensory map. Because mormyromasts are involved in electrolocation behavior, this anatomical difference is probably related to differences in electrolocation abilities. Stomatorhinus could prove to be an excellent system for linking evolutionary changes in behavior with modifications in their neural substrates.

Animals↗
PubMed2002

Pioneering work in vertebrate neural development.

Control of directional axon growth is fundamental to correct wiring in the nervous system, and glia are thought to play an important role. New work in the zebrafish lateral line shows that glia are not required for axonal pathfinding but are required for normal mature nerve organization.

Animals↗
PubMed2001

Auditory and lateral line inputs to the midbrain of an aquatic anuran: neuroanatomic studies in Xenopus laevis.

Computation of rate in auditory signals is essential to call recognition in anurans. This task is ascribed to a group of central nervous system nuclei in the dorsal midbrain or torus semicircularis, homologous to the inferior colliculus of mammals. We have mapped the connections of the subnuclei of the torus semicircularis in Xenopus laevis to determine which receive auditory and which receive lateral line information. Relative to terrestrial anurans, the torus of X. laevis is hypertrophied and occupies the entire caudal, dorsal midbrain. Auditory input to the torus, that arising directly from the dorsal medullary nucleus, is present only in the laminar nucleus. The principal and magnocellular nuclei receive their input from the lateral line nucleus of the medulla. All three nuclei of the torus also have reciprocal connections with the superior olive and the nucleus of the lateral lemniscus. Ascending efferents from all three nuclei of the torus innervate central and lateral thalamic nuclei, and all have a weak reciprocal connection with the posterior thalamus. The laminar and magnocellular nuclei have reciprocal connections with the ventral thalamus, and all three nuclei of the torus receive descending input from the anterior entopeduncular nucleus. The laminar and magnocellular nuclei also receive descending input from the preoptic area. Based on our identification of toral nuclei and these results we assign a major function for the detection of water-borne sounds to the laminar nucleus and a major function for the detection of near field disturbances in water pressure to the principal and magnocellular nuclei.

Animals↗
PubMed2000

Hair cell heterogeneity and ultrasonic hearing: recent advances in understanding fish hearing.

The past decade has seen a wealth of new data on the auditory capabilities and mechanisms of fishes. We now have a significantly better appreciation of the structure and function of the auditory system in fishes with regard to their peripheral and central anatomy, physiology, behaviour, sound source localization and hearing capabilities. This paper deals with two of the newest of these findings, hair cell heterogeneity and the detection of ultrasound. As a result of this recent work, we now know that fishes have several different types of sensory hair cells in both the ear and lateral line and there is a growing body of evidence to suggest that these hair cell types arose very early in the evolution of the octavolateralis system. There is also some evidence to suggest that the differences in the hair cell types have functional implications for the way the ear and lateral line of fishes detect and process stimuli. Behavioural studies have shown that, whereas most fishes can only detect sound to 1-3 kHz, several species of the genus Alosa (Clupeiformes, i.e. herrings and their relatives) can detect sounds up to 180 kHz (or even higher). It is suggested that this capability evolved so that these fishes can detect one of their major predators, echolocating dolphins. The mechanism for ultrasound detection remains obscure, though it is hypothesized that the highly derived utricle of the inner ear in these species is involved.

Animal Communication↗
PubMed1990

Generational equity and the politics of the welfare state.

The concept of generational equity--that the nation is squandering its wealth on entitlements to the elderly while children remain impoverished--has received considerable media attention. The author traces the source of that message to an organization, Americans for Generational Equity, which is dedicated to restructuring the Social Security system along the lines of a social assistance program: reduced benefits available at later ages only to those who qualify through means tests. The impact of this agenda would be to increase the labor force participation of older people, particularly women and minorities, those presently without private pension coverage and already heavily represented in that sector of the economy where labor shortage is developing. Defining national spending priorities in terms of intergenerational conflict obscures the fact that Social Security is the only U.S. welfare program that has been successful in reducing poverty levels.

Age Factors↗
PubMed2006

[The evaluation of patients undergoing total knee arthroplasty with or without patellar resurfacing].

OBJECTIVES: We evaluated the clinical and radiographic results of total knee arthroplasty (TKA) with or without patellar resurfacing. METHODS: The study included 149 knees of 126 patients who underwent TKA for primary knee osteoarthritis with (59 knees, group 1) or without (90 knees, group 2) patellar resurfacing. Clinical evaluations were made with the knee and function scores of the Knee Society, and patella scoring system; radiographic evaluations included changes in the joint line, Insall-Salvati ratio, lateral patellofemoral angle, and congruency angle. The mean follow-up period was 66.7 months (range 34 to 123 months) in group 1, and 68.1 months (range 30 to 117 months) in group 2. RESULTS: Although postoperative knee and function scores showed significant improvements in both groups (p<0.001), these did not reach significance between the two groups (p>0.05). The mean patella scores did not differ significantly, either (p>0.05). Postoperative radiographic assessments did not show significant differences between the two groups with respect to mechanical axis values, patellar tilt, and lateral subluxation (p>0.05). Symptomatic patellar subluxation, dislocation, fracture or rupture of the extensor mechanism did not occur in any of the treatment groups. None of the patients required revision associated with the patella and patellar prosthesis. CONCLUSION: Our findings suggest that patellar resurfacing is not necessary other than patients with significant degeneration of the patellar surface.

Adult↗
PubMed1999

Aberrant copper chemistry as a major mediator of oxidative stress in a human cellular model of amyotrophic lateral sclerosis.

We have investigated the response to oxidative stress in a model system obtained by stable transfection of the human neuroblastoma cell line SH-SY5Y with plasmids directing constitutive expression of either wild-type human Cu,Zn superoxide dismutase or a mutant of this enzyme (H46R) associated with familial amyotrophic lateral sclerosis. We report that expression of mutant H46R Cu,Zn superoxide dismutase induces a selective increase in paraquat sensitivity that is reverted by addition of D-penicillamine. Furthermore, expression of this mutant enzyme affects the activity of the endogenous wild-type enzyme both in basal conditions and in copper overloading experiments. Our data indicate that aberrant metal chemistry of this mutant enzyme is the actual mediator of oxidative stress and that concurrent impairment of the activity of wild-type endogenous enzyme compromises the cell's ability to respond to oxidative stress.

Amyotrophic Lateral Sclerosis↗