A new, efficient table-drain assembly for endoscopic surgery.
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Drainage, Sanitary↗
Biomedical subjects
L S Ross
Publications and source records attributed to L S Ross.
Axonogenesis and morphogenesis in the embryonic zebrafish brain.
We have examined early neuronal differentiation and axonogenesis in the fore- and midbrain of zebrafish embryos to address general issues of early vertebrate brain development. AChE expression and HNK-1 antibody immunoreactivity were used as markers for differentiated neurons and axons, respectively. The pattern of neuronal differentiation followed a stereotyped sequence. AChE-positive cells first appeared between 14 and 16 hr in three small, isolated, bilaterally symmetrical clusters on the surface of the brain. The three clusters--the dorsorostral, ventrorostral, and ventrocaudal clusters--proved to be the progenitors of the telencephalon, ventral diencephalon, and mesencephalic tegmentum, respectively. With further development, more cells were added to these three clusters, and new clusters appeared in the anlage of the epiphysis (18 hr) and in the pituitary and dorsal mesencephalon (by 24 hr). Subsequently, as more neurons differentiated, the gaps of unlabeled cells were reduced; by 48 hr, the cluster boundaries were indistinguishable. Axonogenesis also followed a stereotyped sequence. The first HNK-1-labeled processes arose from the first three clusters of AChE-positive cells and connected the clusters. The earliest axonal growth cones appeared at 16 hr, directed caudally from two to three neurons of the ventrocaudal cluster and pioneering the ventral longitudinal tract. By 18 hr, the tract of the postoptic commissure was initiated by growth cones directed caudally from the ventrorostral cluster toward the ventrocaudal cluster. By 20 hr, axons from the dorsorostral cluster projected ventrally to form the supraoptic tract. The other dorsoventral tracts (the dorsoventral diencephalic tract and the tract of the posterior commissure) became evident between 20 and 24 hr. These observations provide a continuous record of the topological distortions involved in the conversion of the tubular embryonic brain into the contorted adult form. The telencephalon, ventral diencephalon, and hypothalamus originate from the same rostrocaudal level of the neural tube. The pattern of differentiation demonstrated that the early development of the rostral neural tube occurs simultaneously in several independent centers, similar to the overtly segmental development of the hindbrain.
Acetylcholinesterase↗
Molecular cloning and characterization of the B subunit of a vacuolar H(+)-ATPase from the midgut and Malpighian tubules of Helicoverpa virescens.
Using the polymerase chain reaction (PCR) a 0.8-kb product was amplified from cDNA made from the midgut and Malpighian tubules of fifth instar larvae of Helicoverpa virescens. This 0.8-kb PCR product was then used to isolate a clone of the B subunit of the V-type ATPase from a cDNA library made from the same tissues. The cDNA clone encodes for a protein of 55 kDa which shows very high amino acid homology to other known B subunits of V-type ATPases. The transcript size of the B subunit in the midgut of H. virescens was 2.3 kb, and a transcript of identical size was also detected in the Malpighian tubules. Northern blot analysis revealed the presence of a homologous transcript of 2.6 kb in the midgut of Manduca sexta and PCR analysis also confirmed the presence of such a transcript in the Malpighian tubules and the nervous system of M. sexta, and in the midgut Malpighian tubules of Culex quinquefasciatus. The presence of the V-type ATPase in the Malpighian tubules of lepidopteran insects suggests that the transport of ions across the cell membrane in this tissue is also probably driven by a similar process as that observed in the midgut of these insects.
Amino Acid Sequence↗
Azoospermia: a complication of hydrocele repair in a fertile population.
Although minor complications have been reported, hydrocelectomy generally is considered to be a safe procedure. We recently treated 3 patients who became azoospermic after hydrocele repair. Of the patients 2 underwent bilateral and 1 unilateral hydrocelectomy. All 3 patients had iatrogenic injury to the vas deferens or epididymis after hydrocele repair.
Adult↗
Reporting impaired physicians.
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Clinical Competence↗
Initial clinical trials with a tubless lithotriptor.
The Medstone 1050 is a new tubeless lithotriptor developed in the United States. Under Food and Drug Administration guidelines a human treatment protocol has been developed. The first 50 patients treated at a single site and followed for a minimum of 3 months are presented. All stones treated were 3 cm. or less in longest dimension and located in the renal pelvis, calices or proximal ureter. An adequate fragmentation rate of 90% was achieved in this group. There were no significant complications in any patient. A larger multicenter study presently is underway.
Humans↗
The development of a simple scaffold of axon tracts in the brain of the embryonic zebrafish, Brachydanio rerio.
We have examined neuronal differentiation and the formation of axon tracts in the embryonic forebrain and midbrain of the zebrafish, between 1 and 2 days postfertilisation. Axons were visualised with three techniques; immunocytochemistry (using HNK-1 and antiacetylated tubulin antibodies) and horseradish peroxidase (HRP) labelling in whole-mounted brains, and transmission electron microscopy. Differentiation was monitored by histochemical staining for acetylcholinesterase (AChE). These independent methods demonstrated that a simple grid of tracts and commissures forms the initial axon scaffold of the brain. At 1 day, the olfactory nerve, four commissures, their associated tracts and three other non-commissural tracts are present. By 2 days, these tracts and commissures have all greatly enlarged and, in addition, the optic nerve and tract, and three new commissures and their associated tracts have been added. Small applications of HRP at various sites revealed the origins and projections of some of these earliest axons. Retrogradely labelled cell bodies originated from regions that were also positive for AChE activity. At 1 day, HRP-labelled axons were traced: (1) from the olfactory placode through the olfactory nerve to the dorsal telencephalon; (2) from the telencephalon into the tract of the anterior commissure and also to the postoptic region of the diencephalon; (3) from the hindbrain through the ventral midbrain and diencephalon to the postoptic commissure; (4) from the dorsal diencephalon (in or near the epiphysis) to the tract of the postoptic commissure; (5) from ventral and rostral midbrain through the posterior commissure. Three new projections were demonstrated at 2 days: (1) from the retina through the tract of the postoptic commissure to the tectum; (2) from the telencephalon to the contralateral diencephalon; and (3) from the telencephalon to the ventral flexure. These results show that at 1 day, the zebrafish brain is impressively simple, with a few small, well-separated tracts but by 2 days the brain is already considerably more complex. Most of the additional axons added onto pre-existent tracts rather than pioneered new ones supporting the notion that other axons play a crucial role in the guidance of early central nervous system (CNS) axons.
Acetylcholinesterase↗
Differential ascending projections to aural regions in the 60 kHz contour of the mustache bat's inferior colliculus.
The inferior colliculus of the mustache bat is similar in many respects to the inferior colliculus of more commonly studied mammals. However, the isofrequency contour devoted to processing 60 kHz, the dorsoposterior division (DPD) is greatly expanded, encompassing an area approximately equal to one-third of the central nucleus. Of particular significance is that monaural and binaural neurons are segregated in the DPD into 4 spatially distinct aural regions. In this study we exploit the great enlargement of the 60 kHz region in the central nucleus of the inferior colliculus (ICc) of the mustache bat to determine the source of ascending projections to the 4 different aural regions of the DPD. Small iontophoretic deposits of HRP were made within each of the physiologically defined aural regions, and the locations and numbers of retrogradely labeled cells in the auditory brainstem nuclei were determined. Two major features of collicular organization were found. The first is that each aural region receives a unique set of projections from a subset of lower auditory nuclei and thus is distinguished both by its neural response properties and by the pattern of ascending projections it receives. The dorsomedial EE region receives inputs primarily from the ipsilateral intermediate nucleus of the lateral lemniscus (INLL) and ventral nucleus of the lateral lemniscus (VNLL), and the contralateral ICc. In contrast, the ventrolateral EE region receives projections from the ipsilateral medial superior olivary nucleus (MSO), VNLL, and INLL. The inputs to the EI region originate primarily from the dorsal nucleus of the lateral lemniscus (DNLL) and lateral superior olivary nucleus (LSO) bilaterally and from the ipsilateral INLL. The afferents to the EO region include the contralateral cochlear nucleus, the ipsilateral VNLL and INLL and MSO. The second major organizational feature is that the binaural nuclei of the brain-stem project upon the DPD in a more restricted manner than do some of the lower monaural nuclei, such as the VNLL and INLL, which project in a more widespread manner. The unique set of projections terminating in each aural region of the DPD suggests that the neurons should have substantially different properties, even when neurons in different regions are of the same general aural type. Moreover, the elucidation of the micro-organization of the DPD provides insights into the different ways that binaural properties of DPD neurons are created by the convergence of inputs from particular subsets of lower auditory nuclei.(ABSTRACT TRUNCATED AT 400 WORDS)
Afferent Pathways↗
Origin of ascending projections to an isofrequency region of the mustache bat's inferior colliculus.
The inferior colliculus of the mustache bat is similar in most respects to the inferior colliculus of more commonly studied mammals, but one isofrequency contour, the dorsoposterior division, is greatly overrepresented. The present study utilizes this specialization of the auditory system in the mustache bat to determine the total set of ascending projections to a single isofrequency contour of the inferior colliculus. Within the dorsoposterior division, neurons are all very narrowly tuned to 60 kHz, the major component of this bat's echolocation call. The afferent projections to this isofrequency contour were identified by making deposits of horseradish peroxidase (HRP) within the dorsoposterior division after physiologically defining its borders. Two other frequency representations are present in the central nucleus of the inferior colliculus of the mustache bat, the anterolateral division in which there is an orderly progression of frequencies from 59 down to 20 kHz, and the medial division in which frequencies from 63-120 kHz are represented. In additional experiments, the afferent projections to the medial and anterolateral divisions were examined, providing an anatomical description of the tonotopicity of the lower auditory nuclei. Deposits of HRP in the DPD labeled cells in each of the lower brainstem auditory nuclei that have previously been shown to project to the entire central nucleus of the inferior colliculus. The ascending projections to the dorsoposterior division include contralateral projections from the cochlear nucleus and inferior colliculus, ipsilateral projections from the medial superior olive, ventral and intermediate nuclei of the lateral lemniscus, and bilateral projections from the lateral superior olive and dorsal nucleus of the lateral lemniscus. In most of the nuclei, labeled cells were confined to specific portions of the nuclei, often forming "slabs" of labeled cells across the rostrocaudal extent of most nuclei. These slabs presumably represent the 60 kHz representation in each of the lower nuclei. When deposits of HRP were made into other frequency band representations of the inferior colliculus, in either the medial or anterolateral division, labeled cells again formed slabs in each lower nucleus. However, the location of the slab varied as a function of the best frequency of neurons at the deposit site, and labeled cells were not present within the 60 kHz representation. These results show the general tonotopy of the mustache bat's brainstem auditory nuclei, and with respect to the dorsoposterior division, clearly reveal the total set of projections to a single isofrequency region.(ABSTRACT TRUNCATED AT 400 WORDS)
Afferent Pathways↗
Adverse reactions to intravascular contrast media.
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Contrast Media↗
Base analogue mutagenesis in yeast and its modulation by pyrimidine deoxynucleotide pool imbalances: incorporation of bromodeoxyuridylate and iododeoxyuridylate.
Cells of the yeast, Saccharomyces cerevisiae, which are auxotrophic for thymidylate (tmpl) can also incorporate analogues of thymidylate. When the base analogue, 5-bromodeoxyuridylate, is incorporated into tmpl yeast cells it is lethal and mutagenic. Both lethality and mutation induction can be drastically altered by perturbation of the pyrimidine nucleotide pools. Analysis of mutation induction, bromodeoxyuridylate incorporation into DNA, and cell viability under various conditions revealed: (1) lethality and mutagenesis can be uncoupled, (2) thymidylate enhances mutagenesis and deoxycytidylate suppresses it, (3) mutation induction is not correlated with the magnitude of bromodeoxyuridylate incorporation into DNA. Therefore, in yeast, the pyrimidine nucleotide pools have a powerful effect on bromodeoxyuridylate mutagenesis. Both bromodeoxyuridylate and iododeoxyuridylate are extensively incorporated into the DNA of tmpl yeast cells; however, iododeoxyuridylate is non-mutagenic. Replication proceeds at the same rate in the presence of the natural substrate or either analogue. When cells are supplied with thymidylate and bromodeoxyuridylate together, there is no discrimination against bromodeoxyuridylate as a DNA precursor. However, in the presence of thymidylate and iododeoxyuridylate, there is a 3 to 1 discrimination against iododeoxyuridylate as compared to thymidylate.
Carbon Radioisotopes↗
Alloplastic spermatoceles: a 5-year experience.
We implanted 14 alloplastic spermatoceles in 8 patients with congenital absence or atresia of the vas deferens or anejaculation. The surgical technique and results of aspirations are detailed. Five spermatoceles yielded sperm: 2 for prolonged periods (4 1/2 to 11 months) and 1 produced motile sperm considered adequate for artificial insemination.
Female↗
Binaural response organization within a frequency-band representation of the inferior colliculus: implications for sound localization.
The auditory system of the mustache bat (Pteronotus parnellii) contains a disproportionately large representation of a narrow frequency band, corresponding to the dominant, 60 kHz component of its echolocation signal. In the inferior colliculus (IC), the 60 kHz representation comprises an architectonically distinct region called the dorsoposterior division (DPD), which is accessible for detailed physiological study. We examined the topographic distribution of binaural responses within this one frequency-band representation of the inferior colliculus. We describe two primary results. First, neurons with different binaural response properties are spatially segregated into one of four binaural response-specific regions of the DPD: a large region of monaural (EO) responses; two regions containing neurons excited by sound from both ears (EE); and a region containing neurons excited by one ear and inhibited by the other (EI). Regions dominated by 60 kHz EI responses are also found in the lateral extremity of the IC, probably within the external nucleus. These results demonstrate functionally defined subdivisions in a single frequency-band representation of the IC. Moreover, they suggest that brain stem auditory projections to the DPD and/or intrinsic connections within the DPD are highly organized. Second, within the EI region of the DPD, there is a systematic shift in the sensitivity of EI multiunit responses to interaural intensity disparities (IIDs). Dorsally, EI neurons are suppressed only by relatively loud ipsilateral sounds, and there is a systematic decrease in the relative ipsilateral intensity required for suppression at more ventral recording sites. This result demonstrates that neurons sensitive to a sound localization cue are systematically organized within a frequency-band representation of the inferior colliculus. It has implications for the manner in which the location of a sound source is encoded within the primary auditory pathway.
Animals↗
A functional organization of binaural responses in the inferior colliculus.
Binaural responses are segregated within an enlarged isofrequency region of the mustache bat's inferior colliculus. In the part of this region containing E-I responses, there is an orderly shift in the sensitivity of unit clusters to interaural intensity disparities, having implications for the representation of auditory space within isofrequency regions of the inferior colliculus.
Animals↗
Properties of human epididymal sperm obtained from an alloplastic spermatocele: motility assessment and penetration of zona-free hamster oocytes in the presence and absence of caffeine.
Sperm were collected over a period of months from a human alloplastic spermatocele implanted at the corpus/caudal epididymal junction and were evaluated for their maturity, motility, and ability to capacitate and acrosome react, as assessed by the hamster zona-free oocyte sperm penetration assay (SPA). A mean of 11 X 10(6) sperm were obtained with each aspiration, with 34% to 40% being mature, normal forms. Motility was poor; 15% +/- 5% showing nonprogressive movement. SPA results were 22% +/- 3% oocyte penetration. Addition of 7.5 mM caffeine markedly enhanced motility and improved the SPA results. After 30 minutes' exposure, the motility was 45% +/- 5%, with all spermatozoa exhibiting progressive movement. This stimulation was maintained over a 24-hour period. When caffeine was present during the 2-hour preincubation for the SPA, penetration rates increased to 50% +/- 10% (P less than 0.05). These results demonstrate that the poor-quality sperm retrieved from a human alloplastic spermatocele can be improved with exogenous stimulation and suggest that their fertilizing capacity may be enhanced by this treatment.
Adult↗
Evaluation and treatment of the infertile man.
Increasing numbers of patients are seeking treatment for infertility. The primary care physician is often the first professional to face this diagnostic challenge. Recent developments in the diagnosis and treatment of the infertile man have led to increased success in management of the infertile couple. This article reviews these developments.
Chorionic Gonadotropin↗
Effect of metabolic inhibitors on vasopressin-stimulated transport systems in the toad bladder.
Vasopressin increases the permeability of receptor cells to water and, in tissues such as toad bladder, to solutes such as urea. While cyclic AMP appears to play a major role in mediating the effects of vasopressin, there is evidence that activation of the water permeability system and the urea permeability system involves separate pathways. In the present study, we have shown that inhibitors of oxidative metabolism (rotenone, dinitrophenol, and methylene blue) selectively inhibit either vasopressin-stimulated water flow or vasopressin-stimulated urea transport. There was no inhibition, however, when exogenous cyclic AMP was substituted for vasopressin, and little to no inhibition when the potent analogue 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) was employed. Rotenone had no effect on adenylate cyclase activity or cyclic AMP levels within the cell; dinitrophenol decreased adenylate cyclase activity minimally. Additional studies with vinblastine and nocodazole, inhibitors of microtubule assembly, demonstrated an inhibition of vasopressin and cyclic AMP-stimulated water flow but showed no effect on urea transport. We would conclude that water and urea transport, as examples of hormone-stimulated processes, have different links to cell metabolism, and that in addition to cyclic AMP, a non-nucleotide pathway may be involved in the action of vasopressin.
Adenylyl Cyclases↗
What about the other kidney?
Sophisticated diagnostic techniques have made the isolation of renal lesions more accurate. However, it must be remembered that simultaneous bilateral kidney pathology can exist in any patient. The most obvious lesion may not be the most important. Four cases are presented to illustrate this point.
Aged↗