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Biomedical subjects

K M Klueber

Publications and source records attributed to K M Klueber.

14 recordsLinked to original sources
PubMed2001

Adult human olfactory stem cells.

The location of stem cells within the adult CNS makes them impractical for surgical removal and autologous transplantation. Their limited availability and histocompatibility issues further restrict their use. In contrast, olfactory neuroepithelium (ONe) located in the nasal passageways has a continuous regenerative capability and can be biopsied readily. To investigate the potential of human ONe to provide viable populations of pluripotent cells, ONe was harvested from cadavers 6-18 h postmortem, dissociated, plated and fed every 3-4 days. Heterogeneous populations of neurons, glia, and epithelia were identified with lineage-specific markers. After several weeks, 5-10% of the cultures produced a population of rapidly dividing cells, which in turn, produced neurospheres containing at least two subpopulations based on neuronal and glial specific antigens. Most contained one or more neuronal markers; a few were positive for A2B5 and/or GFAP. To determine if growth modulators would affect the neurosphere forming cells, they were exposed to dibutyryl-cAMP. The nucleotide reduced cell division and increased process formation. Although the cells had been passaged more than 70 times, their viability remained constant as shown by the MTT viability index. Donor age or sex were not limiting factors, because neurospheres have been established from cadavers of both sexes from 50 to 95 years old at time of death. The ex vivo expansion of these cells will provide a patient-specific population of cells for immunological, genetic and pharmacological evaluation. Our long-term goal is to determine the utility of these cells to facilitate CNS repair.

Aged↗
PubMed1994

Ultrastructural, histochemical, and morphometric analysis of skeletal muscle in a murine model of type I diabetes.

BACKGROUND: Since peripheral nerves are damaged in diabetes mellitus, morphological changes occur within the diabetic muscle in response to the diabetic neuropathy. The aim of this study was to examine the extensor digitorum longus (EDL) from a 42-day streptozotocin-induced diabetic Swiss Webster mouse (STZ) and compare the muscle morphology and histochemistry to age-matched, nondiabetic controls. METHODS: The EDL was evaluated using electron microscopy in order to investigate the morphological integrity of the myofibers and neuromuscular junctions. Histochemical analysis was completed using the myofibrillar CA(++)-ATPase reaction of Doriguzzi et al. (1983. Histochemistry, 79:289-294) for use in computer-assisted morphometric analysis of fiber size using Bioquant System 4 software. RESULTS: Ultrastructural analysis of the diabetic EDL (N = 5, 225 myofibers/animal) showed a significant number of abnormal myofibers, exhibiting various degrees of degeneration, signs of denervation, and necrosis. The STZ myofibers exhibited excessive lipid accumulations and abnormal mitochondrial arrangements. Histochemical analysis of the STZ EDL revealed a significant shift in fiber type profile (53.6% type 2A and 46.4% type 2B- STZ myofibers; 47.5% type 2A, 52.5% type 2B nondiabetic controls). Morphometric analysis of myofiber size by fiber type (200 myofibers/muscle/fiber type) indicated a significant decrease in myofiber size for both type 2A and type 2B fibers in the STZ diabetic mouse. CONCLUSION: The degeneration and necrosis of myofibers concomitant with the sever atrophy of both the type 2A and 2B myofibers in the STZ muscle could account for the functional alterations seen in diabetic muscle.

Animals↗
PubMed1994

Supplemental complement component C9 enhances the capacity of neonatal serum to kill multiple isolates of pathogenic Escherichia coli.

Previous studies demonstrated that, compared with adult serum, neonatal serum contained a diminished concentration of complement component C9 and that supplemental C9 enhanced the capacity of neonatal serum to kill an isolate of Escherichia coli. Therefore, experiments were designed to determine the mechanisms by which supplemental C9 enhances the bactericidal capacity of neonatal serum and to determine whether supplemental C9 enhances the capacity of neonatal serum to kill several different pathogenic strains of E. coli. A radiobinding assay and immunogold electron microscopy using a monoclonal anti-C9 antibody revealed that, compared with 40% adult serum, neonatal serum deposited a diminished quantity of C9 onto E. coli O7w:K1:NM. Supplemental C9 (75 mg/L) significantly enhanced the quantity of C9 deposited by the neonatal serum. Treatment with 10 mM MgEGTA (a mixture of 100 mM MgCl2 and 100 mM EGTA that blocks activation of the classic complement pathway but leaves the alternative pathway intact) abolished the capacity of neonatal serum to deposit C9 and to kill the bacteria. Supplemental C9 enhanced the capacity of neonatal serum to kill eight different blood isolates of E. coli. Therefore, supplemental C9 enhanced the capacity of neonatal serum to kill E. coli by increasing the total quantity of C9 deposited via activation of the classic complement pathway. Neonatal serum contained sufficient quantities of classic pathway components, other than C9, to deposit the supplemental C9 onto E. coli and to enhance bacterial killing. The bactericidal activity of neonatal serum against multiple isolates of pathogenic E. coli was increased after C9 supplementation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Skeletal muscle following tonic overload: functional and structural analysis.

Functional overloading of skeletal muscle induces a compensatory hypertrophy as an adaptive response to increased functional demand. Overload of the extensor digitorum longus (EDL) muscle (129 ReJ strain male mouse) was induced by unilateral surgical removal of a synergistic muscle, tibialis anterior (TA). Response of the EDL to overload for 7, 21, and 42 d was analyzed for changes in 1) muscle weight, 2) myofiber type distribution, 3) myofiber cross-sectional area by fiber type, 4) speed of contraction and relaxation of the muscle, 5) force of contraction, and 6) myofiber morphologic integrity. The weight of the EDL significantly increased. The overload caused no impairment of muscle contractility and did not have a significant effect on isometric twitch contraction time to peak tension or the time to one-half relaxation of the twitch. Overloaded muscles demonstrated a transient shift in fiber type profile with preferential hypertrophy of Type IIA fibers that occurred in the early phase of overload while type IIB fibers were recruited by 42 d. No significant increase in myofiber number in overloaded muscles occurred. Some morphologic changes in over-loaded muscles parallel those found in patients with neurogenic muscular disorders. However, overloaded muscle did not exhibit a significant occurrence of fiber branching from controls in the midbelly region of the muscle.

Adaptation, Physiological↗
PubMed1989

Skeletal muscle in the diabetic mouse: histochemical and morphometric analysis.

Despite the extensive literature concerning the neuropathy associated with diabetes, only limited information describes changes in the associated muscle. The objective of this study was to evaluate the histochemical and morphometric characteristics of diabetic muscle in the C57BL/KsJ db-m strain of mouse. The histochemical analysis of myofiber type for the diabetic mouse revealed that the extensor digitorum longus muscle consisted of 53.1% type 2a, 46.0% type 2b, and 0.9% type 1 myofibers, a significant shift from the percentages found in the nondiabetic litter mates (44.4% type 2a, 55.6% type 2b, no type 1). Computer-assisted morphometric analysis of myofiber size by fiber type indicated a significant difference in myofiber size for the type 2b fibers in muscles from diabetic mice. Similarly, there was a shift in the fiber size distribution to include a greater number of small type 2b myofibers when compared to controls. Skeletal muscle from diabetic mice exhibited a significant change in the percentage of fiber types, with an increase in the number of type 2a fibers, a fiber type grouping that implies possible denervation and reinnervation, and a decrease in myofiber size. These findings may explain why some diabetic patients complain of muscle weakness.

Animals↗
PubMed1989

Structural and functional analysis of murine skeletal muscle after castration.

A previous histochemical and morphometric study demonstrated that castration caused a significant decrease in myofiber and muscle size in the extensor digitorum longus (EDL) muscles of male ReJ 129 mice. The objective of the present study was to examine the effects of castration on the morphology and physiology of the EDL. Muscle wet weight was significantly decreased in the castrated group. The morphological survey demonstrated a significant degree of degeneration in the EDL muscles from castrated animals, consisting of disruption of normal myofilament arrangement and necrosis, invasion of active macrophages, and atrophic myofibers. These findings were significantly correlated with the decrease in peak tension observed in the castrated groups. No significant difference was detected in the time to peak tension and half-relaxation time in the castrated groups compared with the control. Thus, alterations of the morphological integrity and myofiber size of skeletal muscle affect muscle strength in castrated animals.

Animals↗
PubMed1988

Cytoarchitecture of muscle in a genetic model of murine diabetes.

Although diabetic neuropathy is well documented, diabetic myopathy is not, except for descriptions of diabetic patients with muscular weakness thought to be due to metabolic changes in the muscle. Muscle and nerve are dependent on each other for normal structure and function; since the peripheral nerve is damaged in diabetes, one would expect concomitant changes in the muscle. This study examines the cytoarchitecture of diabetic muscle. The extensor digitorum longus (EDL) muscles from 165-day-old C57BL/KsJ dbm mice were examined using electron microscopy. Morphological analysis of the diabetic EDL revealed that a significant number of the myofibers, examined within the midbelly region of the muscle, exhibited various degrees of degeneration, signs of denervation, and abnormal lipid stores. Both myoneural junctions and muscle spindles showed significant signs of degeneration, denervation, and abnormal structure. Thus the morphologic changes seen could account for the physiologic changes seen in diabetic muscle.

Animals↗
PubMed1988

Hepatic phase II biotransformation in C57Bl/KsJ db/db mice: comparison to that in Swiss Webster and 129 REJ mice.

1. Cytochrome P-450 concentrations were similar in male and female carrier (db/+) and diabetic (db/db) mice. Benzphetamine N-demethylase and styrene oxide hydrolase activities were 47 and 65% lower in db/+ than in db/db mice. 2. UDP-Glucuronosyltransferase activity toward 1-naphthol, estrone and diethylstilbestrol was not different between db/db and db/+, but was 40% higher in db/db mice toward testosterone. 3. Glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene and ethacrynic acid was 47 and 59% lower in db/db mice than in male db/+ mice. Female db/+ mice had similar activities to those found in diabetic animals. 4. The differences in enzyme activity between hyperinsulinemic and normal animals suggest that insulin can influence both phase I and phase II biotransformations. 5. Enzyme activities in db/+ and db/db mice were compared to those in 129 REJ and Swiss Webster mice.

Animals↗
PubMed1987

Morphometric analysis of neuronal soma size within the motor nucleus of a transplanted murine skeletal muscle.

Since the number of motor neurons supplying a muscle graft is reduced, the peripheral field for the surviving motor neurons would be enlarged. This possible change in motor unit size may result in morphologic changes in the size of motor neurons within the motor neuron pool of the graft. The extensor digitorum longus (EDL) muscle from 19 transplanted and 17 age-matched normal 129 ReJ female mice were injected with horseradish peroxidase in order to examine the cell size distributions of the motor neuron pools supplying these muscles. Computer-assisted morphometric analysis of cell sizes within the motor neuron pool to the transplants indicated a significant shift in cell size, with the largest areas ranging between 630 and 1250 micron2. A number of the alpha neurons supplying the grafts were twice the average cell size for the control population (means = 592 micron2). The increase in the number of large motor neurons indicates an hypertrophy of neurons reinnervating the grafts. The long-term graft is reinnervated by a decreased population of motor neurons (means = 7), which vary in size from small to very large, reflecting both changes in the possible source of the nerve reinnervating the graft as well as alteration in the size of the motor unit, respectively.

Animals↗
PubMed1987

Role of muscle neurotization in the reinnervation of murine muscle grafts.

Although the reinnervation of muscle grafts has been demonstrated, the question remains as to the source of neurons reinnervating the graft. A muscle graft could be reinnervated by its original neurons (neural neurotization) or by sprouting of axons which supply the intact myofibers of surrounding muscles (muscle neurotization). The objective of this study was to evaluate the role of muscle neurotization in the reinnervation process using both horseradish peroxidase and fluorescent tracers. Observations from 20 muscle grafts indicate that the neurons reinnervating the grafts are from the original motor neuron pool. Thus muscle neurotization may not occur during the reinnervation process.

Animals↗
PubMed1984

A new approach to intramuscular placement of horseradish peroxidase.

A new method of intramuscular placement of a semisolid paste of horseradish peroxidase (HRP) using a root canal file is described. This method has been demonstrated to produce consistent and reproducible numbers of labeled motoneurons in the mouse extensor digitorum longus muscle (EDL). While the number of labeled cells is similar to that found with optimal intramuscular injection of liquid HRP, this new technique provides more reproducible results by eliminating the reflux often associated with intramuscular injection of liquid HRP.

Animals↗
PubMed1979

The morphology of M. palatoglossus in the 15-week human fetus.

The morphology of M. palatoglossus in the 15-week fetus was studied with the aid of 30-micron serial sections. The sample included 26 specimens, 9 each of which were sectioned in the coronal and sagittal planes and 8 which were sectioned transversely. M. Palatoglossus extends within the anterior pillar to attachments in both the soft palate and the tongue. Characteristically, the muscle fibers radiate within the velum, not only along its antero-posterior axis but superiorly as well, to intersect other palatal structures. Within the root of the tongue, some fibers of M. palatoglossus combine in a longitudinal muscular complex to course anteriorly toward the tip, others appear to join the transverse muscular system. These data are compared with the literature describing the morphology of this musculature in the adult.

Female↗
PubMed1979

The morphology of the vertical and transverse intrinsic musculature of the tongue in the 15-week human fetus.

The attachments, courses and interrelationships of the transverse and vertical intrinsic muscle masses of the tongue were examined in 28 fifteen-week fetal specimens. Observations were made from 30-micron sections cut through the tongue in one of the three standard planes of section. Both sets of muscululature are qualitatively well-developed by this time period in fetal life. The transverse fibers were found to occupy the entire length of the tongue. They attach to the lamina propria of the lateral aspect of the body of the tongue and, in the root, to perimysial and adventitial connective tissue. In addition, some fibers were observed to be confluent with the mm. palatoglossus, tonsilloglossus and pharyngis superior. Medially, transverse fibers were found for the most part to terminate in the dense ventral aspect of the median septum. Vertical fibers are present from a point slightly posterior to the tip of the tongue to the level of the foramen cecum, beyond which they become sparse. All vertical fibers attach superiorly to the dorsal lamina propria. In the free part of the body, their ventral attachment, likewise, is to lamina propria. In the middle part of the tongue and, to a greater extent, in the root (as the inferior and lateral free surface decreases) these fibers attach in either the fascial plane underlying the transverse component or to the perimysium of longitudinally-running muscle bundles.

Connective Tissue↗