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C Hildebrand

Publications and source records attributed to C Hildebrand.

At least 37 records · Page 2Linked to original sources
PubMed1999

Indirect effect of sciatic nerve injury on the epidermal thickness of plantar glabrous skin in rats.

In patients with nerve injuries, the skin over the denervated part tends to atrophy. Few experimental studies have dealt with this issue. In this paper we examine the effects of nerve injury on the epidermis in plantar glabrous skin in rats. Analysis of paraffin sections showed that the epidermis becomes abnormally thin after sciatic neurotomy and suture or neurectomy, but not after nerve crush. Autoradiographic analysis showed a subnormal number of thymidine-labelled epidermal cells in plantar skin of rats subjected to sciatic neurectomy. However, after selective division of the sciatic foot branches, with preserved function of thigh and leg muscles, the number of labelled epidermal cells did not differ significantly between the side operated on and the control side. We conclude that the effect of sciatic nerve division on plantar skin in rats is caused by the motor deficiency in the foot rather than by deficient innervation of the skin.

Analysis of Variance↗
PubMed1999

Molecular heterogeneity of oligodendrocytes in chicken white matter.

The classical studies by Del Rio Hortega (Mem. Real. Soc. Espan. Hist. Nat. 14:40-122, 1928) suggest that the oligodendrocyte population includes four morphological subtypes. Recent data from the cat and the rat show that the anatomy of oligodendrocytes related to early myelinating prospective large fibers differs from that of oligodendrocytes related to late myelinating prospective small fibers. After application of a polyclonal antiserum to cryostat sections from the chicken CNS, we noted that glial cells in the spinal cord white matter had become labeled. Analysis of the occurrence and cellular localization of this immunoreactivity--the T4-O immunoreactivity--in the CNS of the adult chicken showed that T4-O immunoreactive cells are enriched in the ventral funiculus and superficially in the lateral funiculus of the spinal cord, where they are co-localized with large fibers. Double staining with T4-O antiserum and anti-GFAP or the lectin BSI-B4 revealed that T4-O immunoreactive cells are not astrocytes or microglia. Staining with anti-HSP108, a general marker for avian oligodendrocytes, showed that T4-O immunoreactivity defines an oligodendroglial subpopulation. A search for T4-O immunoreactivity in spinal cord white matter of some other vertebrates revealed that T4-O immunoreactive cells are not present in sections from fish, frog, turtle, rat, and rabbit spinal cord white matter. These results suggest the presence of a fiber size-related molecular heterogeneity among chicken white matter oligodendrocytes.

Animals↗
PubMed1999

Telemedicine and diabetes.

Telecommunication technology has reached a maturity which can effectively support the promotion of health, prevention and management of diseases and rehabilitation. To achieve effective support harmonization and interoperability of technologies are main requirements. This article tries to point out how interoperability is being met and how the requirements are being applied using DIABCARD as an example. DIABCARD has developed a chip card based medical information system for the care of persons with diabetes.

Computer Security↗
PubMed1998

Neuropathy in diabetic BB/Wor rats treated with insulin implants.

To elucidate the pathophysiology of diabetic neuropathy many workers have examined nerve specimens from diabetic rats. While most workers found that animals with high blood glucose levels develop neuropathy, some researchers report that the peripheral nerves are normal in hyperglycaemic rats. Hypoglycaemia may also cause neuropathy. Some workers suggest that neuropathy is linked to fluctuations of the blood glucose level. In the present study we examine plantar nerves of diabetic BB/Wor rats maintained on an eu-/hyperglycaemic or an eu-/hypoglycaemic regime with insulin implants. Treatment with implants worked well. Light microscopic examination of nerve fibres in non-diabetic control rats and in eu-/hyperglycaemic diabetic rats showed a normal picture. Preparations from eu-/hypoglycemic rats showed irregular myelin sheaths and signs of Wallerian degeneration. The lengths and diameters of the largest internodes were significantly subnormal. We conclude, that periodic moderate hypoglycaemia, but not periodic moderate hyperglycaemia, elicits neuropathy in diabetic BB/Wor rats treated with insulin implants.

Animals↗
PubMed1998

Hypoglycaemic neuropathy in BB/Wor rats treated with insulin implants: electron microscopic observations.

Insulin-dependent diabetes mellitus is a chronic metabolic disease that causes long-term secondary complications such as neuropathy. The occurrence of diabetic neuropathy has generally been thought of as being associated with hyperglycaemia. However, in a previous light microscopic examination of plantar nerves in diabetic BB/Wor rats treated with insulin implants we found that eu-/hyperglycaemic rats present a normal picture, whereas eu-/hypoglycaemic rats show severe changes. The aim of the present work is to supplement our previous light microscopic report with electron microsocpic data from the lateral plantar nerve of normal, eu-/hyperglycaemic and eu-/hypoglycaemic BB/Wor rats. Under the electron microscope lateral plantar nerves collected from eu-/hyperglycaemic rats presented a qualitatively normal picture. In addition, the fibre numbers and the size distribution of the myelinated fibres were normal. In contrast, specimens from eu-/hypoglycaemic BB/Wor rats showed severe qualitative changes, interpreted as signs of axonal de- and regeneration. The total number of axons was somewhat subnormal and the sizes of the myelinated fibres were strongly shifted towards smaller diameters. These data confirm our previous light microscopic observations. We conclude that eu-/hypoglycaemic BB/Wor rats treated with insulin implants, but not similarly treated eu-/hyperglycaemic animals, develop a neuropathy in their plantar nerves.

Animals↗
PubMed1998

Repair of the mandibular branch of the rat facial nerve through transmedian grafting in one or two stages. Functional evaluation.

A previous study examined the morphological outcome of axonal regeneration in the mandibular branch (ramus marginalis mandibulae) of the rat facial nerve after transmedian nerve grafting in one or two stages. The present study supplements the morphological data with a functional evaluation. Recordings of the force of tetanic muscle contractions elicited through stimulation of the mandibular branch showed that upper and lower lip data obtained from animals grafted in one stage did not differ significantly from control data. However, animals grafted in two stages exhibited significantly lower muscle forces compared to one-stage data and to control data. Electromyographic recordings of the M-response showed multiple prolonged potential fluctuations with subnormal amplitudes in grafted cases. In both groups of grafted rats, the mean voltage amplitudes recorded from the upper lip were weaker than the amplitudes seen at the angle of the mouth or the lower lip. The two-stage cases exhibited the most obvious deficit. In conclusion, the present results show that, with respect to the functional restoration achieved three months after nerve injury, repair through transmedian grafting in one stage gives better results than repair in two stages. This finding, which conforms with previous morphological data, suggests that the one-stage procedure should be considered for clinical use.

Animals↗
PubMed1997

The developmental skeletal growth in the rat foot is reduced after denervation.

It has long been known that bone is innervated. In recent years it has been suggested that the local nerves may influence the growth and metabolism of bone by way of neuropeptides. The transient local presence of nerve-containing cartilage canals just before formation of secondary ossification centres in rat knee epiphyses seems to support that view. The purpose of the present study was to see if denervation affects the developmental growth of metatarsal bones in the rat hindfoot. We made sciatic and femoral neurectomies in 7-day-old rat pups and examined the hindfeet at various times after surgery. Immunohistochemical analysis showed that denervation was complete. Radiographic examination revealed that the metatarsal bones were significantly shorter in denervated hindfeet 30 days after denervation (average relative shortening 9.9 +/- 2.3%). Measurements of total foot length showed that denervated feet were subnormally sized already five days postoperatively, before the onset of secondary ossification. The timing of the latter was not affected by denervation. Control rats subjected to tenotomies exhibited normal metatarsal bone lengths. On the basis of these results we suggest that the local nerves may influence the growth of immature bones but do not affect secondary ossification.

Animals↗
PubMed1997

Ganglionic axons in motor roots and pia mater.

In addition to motor axons and preganglionic axons, ventral roots contain unmyelinated or thin myelinated sensory axons and postganglionic sympathetic axons. It has been said that ventral roots channel sensory axons to the CNS. However, it now seems that these axons end blindly, shift to the pia or loop and return towards the periphery and that these units reach the CNS via dorsal roots. Sensory ventral root axons project from a variety of somatic or visceral receptors; some of them are third branches of dorsal root afferents and some seem to lack a CNS projection. Many ventral root afferents contain substance P (SP) and/or calcitonin gene-related peptide (CGRP). These fibres are not affected by neonatal capsaicin treatment and they cannot induce radicular or pial extravasation. Some thin ventral root axons are sympathetic and relate to blood vessels. Afferents containing SP and/or CGRP and sympathetic axons also occur in the spinal pia mater. The sensory axons mediate pain. They might also have vasomotor, tissue-regulatory and/or mechanoreceptive functions. The motor roots of cranial nerves IV, VI and XI contain unmyelinated axons arranged like in ventral roots outside the autonomic outflow. However, the motor root of cranial nerve V channels some unmyelinated axons into the CNS. The occurrence of thin axons in ventral roots and pia mater changes during development and ageing. After peripheral nerve injury, ipsilateral ventral roots and pia are invaded by new sensory and postganglionic sympathetic axons.

Animals↗
PubMed1997

Combined retrograde tracing and immunohistochemistry of trigeminal ganglion neurons projecting to gingiva or tooth pulps in the lower jaw of the cichlid Tilapia mariae.

Rat trigeminal ganglion neurons projecting to the oral mucosa or to tooth pulps have different cell diameters and contain different chemical markers. In the present paper we examine whether trigeminal ganglion neurons sending axons to gingiva or tooth pulps in the lower jaw of the cichlid Tilapia mariae differ in a similar way. Retrograde tracing with fluorescent latex microspheres revealed labelled gingival and pulpal neurons in the caudal part of the trigeminal ganglion. The gingival neurons had a unimodal size distribution (peak 11 microns; range 8-14 microns) and the pulpal neurons exhibited a bimodal size distribution (peaks 12 and 25 microns; range 10-40 microns). Immunohistochemistry revealed a calcitonin gene-related peptide-like immunoreactivity in some 40% of the gingival neurons and a substance P-like immunoreactivity in 30%. Of the small pulpal neurons about 60% exhibited a calcitonin gene-related peptide-like immunoreactivity and 15% showed a substance P-like immunoreactivity. Of the large pulpal neurons some 70% exhibited a calcitonin gene-related peptide-like immunoreactivity. These neurons did not show a substance P-like immunoreactivity. In some animals a few trigeminal ganglion neurons showed a neuropeptide Y- or a vasoactive intestinal polypeptide-like immunoreactivity. Perikarya with a tyrosine hydroxylase- or a choline acetyl transferase-like immunoreactivity were not observed. We conclude that gingiva and tooth pulps in the lower jaw of T. mariae are innervated by trigeminal ganglion neurons, the cell diameters and neuropeptide contents of which differ in a pattern similar to that in the rat. Hence, this seems to represent a conserved evolutionary pattern.

Animals↗
PubMed1997

Repair of the mandibular branch of the rat facial nerve through transmedian grafting in one or two stages. Morphological evaluation.

This study examined by electron microscopy the normal fibre composition of the mandibular branch (MB) of the rat facial nerve and the outcome of axon regeneration in the MB after transmedian grafting in one or two stages. The average normal MB contained 2,185 axons, 17% of which were unmyelinated. The myelinated axons had a unimodal diameter distribution (range 1.5-9.5 microns, mode 4.5 microns). After superior cervical ganglionectomy, the MB lost 1/3 of the C-fibres and 10% of the myelinated axons. In neonatally capsaicin-treated rats the occurrence of unmyelinated axons was reduced by about 50%. After repair in one or two stages the MB contained more myelinated and unmyelinated axons than normal. The myelinated axons showed a unimodal size distribution with a subnormal diameter range. Statistical comparisons showed that MBs from both experimental groups were significantly abnormal with respect to total axon number as well as numbers of unmyelinated and myelinated axons. In these respects the grafted MBs did not differ significantly from each other. However, the myelinated axons in MBs from one-stage cases showed larger mean and maximum diameters compared to MBs from two-stage cases. These data suggest that the normal MB of the rat contains myelinated and unmyelinated sympathetic axons and that about half the C-fibres in the normal MB come from capsaicin-sensitive sensory neurons. The comparison of the two reparative procedures used provides evidence in favor of the one-stage alternative.

Animals↗
PubMed1996

Occurrence of axons with certain immunohistochemical markers in teleost gingiva and teeth.

The occurrence of axons with certain neurochemical markers in gingiva and teeth in the lower jaw of the cichlid Tilapia mariae was examined by immunohistochemistry. It was found that gingival and pulpal axons can be labelled with antibodies against calcitonin gene-related peptide, substance P, tyrosine hydoxylase, neuropeptide Y, choline acetyl transferase and vasoactive intestinal polypeptide. It is concluded that both gingival and dental domains in T. mariae contain axons with sensory and autonomic chemical phenotypes, the occurrence and distribution of which are generally similar to the mammalian counterpart.

Animals↗
PubMed1996

Postnatal development and aging of the rat ventral root L5: electron microscopic and immunohistochemical studies.

The ventral root L5 of neonatal and adult rats has been used in many experimental studies on ganglionic C-fibers. Since the normal presence of such axons in L5 roots from animals of different ages is unknown, the results of these studies cannot be appropriately interpreted. In the present study we examine L5 ventral roots from developing and aging rats in this respect. Electron microscopic examination revealed that C-fibers occur in neonatal roots. The adult proportion has been established at day 30. Immunohistochemical analysis showed that thin ganglionic fibers with substance P/calcitonin gene-related peptide- or tyrosine hydroxylase-like immunoreactivity in the L5 root and the spinal pia mater seem to increase postnatally from low levels at birth. In roots from aged rats, myelinated fibers with a variety of aberrant features occur in normal numbers. The occurrence of unmyelinated axons is elevated. The increased presence of fibers with calcitonin gene-related peptide- or tyrosine hydroxylase-like immunoreactivity in aged roots indicates that the extra unmyelinated fibers may represent motor sprouts and sympathetic fibers, respectively. We conclude that the rat ventral root L5 contains a variable number of putative sensory and sympathetic axons at all ages.

Adrenergic Fibers↗
PubMed1996

Sheath lengths of large motor axons in the ventral root L5 of neonatal and adult rats.

This study examines the developmental sheath elongation in the rat ventral root L5. Electron microscopic analysis of serial transverse sections through roots from newborn rats shows an average internuclear distance (IND) of 66 microns (calculated fresh length 73 microns). Light microscopic analysis of teased adult roots shows that the largest fibers have an average internodal length of some 1250 microns at 5 months. Hence, large fibers exhibit a developmental sheath elongation of 17 times. The ventral root L5 elongates 11 times only. This mismatch necessitates a myelin sheath remodelling.

Aging↗
PubMed1996

Occurrence of epidermal nerve endings in glabrous and hairy skin of the rat foot after sciatic nerve regeneration.

The occurrence and distribution of intraepidermal nerve endings in hairy and glabrous skin of the rat foot was examined in normal cases and three months after sciatic neurotomy/suture or a crush lesion. The nerve endings were visualized in cryostate sections with antibodies against protein gene product 9.5. Normal glabrous skin exhibited 23.3 endings/mm length. Neurotomy/suture cases had 6.1 endings/mm. In rats with nerve crush injury the occurrence was normal, but the intraepidermal nerve endings tended to be abnormally short and occurred mainly in the basal layer of the epidermis. In sections from hairy skin countings were not possible. Subjective evaluation indicated that the occurrence of dermal and epidermal axon profiles usually was very deficient after neurotomy/suture and essentially normal after crush. Skin samples from the contralateral side of operated animals showed a normal occurrence and distribution of nerve endings. We also noted that cases subjected to neurotomy/suture showed increased numbers of protein gene product 9.5-immunoreactive intraepidermal cells and an abnormally thin epidermis. We suggest that a highly deficient occurrence of intraepidermal nerve endings may be one factor behind the unsatisfactory restitution of the sensory function of the hand typically seen in patients subjected to neurotomy and suture.

Animals↗
PubMed1996

Regeneration of putative sensory and sympathetic cutaneous nerve endings in the rat foot after sciatic nerve injury.

The present study examines the occurrence of calcitonin gene-related peptide-, substance P- and tyrosine hydroxylase-like immunoreactive profiles in glabrous and hairy foot skin from normal and nerve-injured rats. After neurotomy/suture, glabrous skin samples contain few calcitonin gene-related peptide-, substance P- and tyrosine hydroxylase-like immunoreactive profies. The number of calcitonin gene-related peptide- and substance P-like immunoreacive profiles in the epidermis is significantly subnormal. Hairy skin from these rats does also contain few calcitonin gene-related peptide-, substance P- and tyrosine hydroxylase-like immunoreactive profiles. In addition, the presence of epidermal calcitonin gene-related peptide-like imunoreactive profiles in glabrous skin is subnormal on the contralateral side. After nerve crush injury, the occurrence of calcitonin gene-related peptide-like, but not substance P-like, immunoreactive profiles in th epidermis of the glabrous skin is significantly subnormal. The occurrence of tyrosine hylase-like immnunoreactive fibres in relation to the digital artery is also subnormal. The occurrence in hairy skin of calcitonin gene-related peptide-like immunoreactive, substance P-like immunoreactive and tyrosine hydroxylase-like immunoreactive profiles is subnormal. In both skin types, the contralateral occurrence of such profiles is subjectively normal. These results show that the occurrence of calcitonin gene-related peptide-, substance P-, and tyrosine hydroxylase-like immunoreactive profiles in glabrous and hairy foot skin is clearly subnormal after neurotomy and suture and less abnormal after nerve crush. After neurotomy and suture the contralateral side is also affected.

Animals↗
PubMed1995

Resolution of the steroid-binding and dimerization domains of human sex hormone-binding globulin by expression in Escherichia coli.

To determine the minimal sequence requirements for steroid binding and dimerization of human sex hormone-binding globulin (SHBG), the SHBG polypeptide and various SHBG deletion mutants were expressed as glutathione S-transferase (GST) fusion proteins in Escherichia coli. Fusion proteins containing the complete SHBG sequence, or the first 177 N-terminal residues of SHBG, bound steroids with high affinity and specificity. Further deletions from the C-terminus severely compromised steroid-binding activity, as did N-terminal deletions beyond residue 18 in the SHBG sequence. Thus, residues 18-177 in SHBG encompass a region required for its steroid-binding activity, and a disulfide bridge normally present between Cys-164 and Cys-188 in SHBG is not obviously essential for steroid binding. Most of the GST/SHBG fusion proteins undergo cleavage at 4 degrees C, releasing immunoreactive polypeptides that correspond approximately in size to their respective SHBG sequences. The 23-kDa immunoreactive cleavage product released from the fusion protein containing residues 1-205 in the SHBG sequence (SHBG 1-205) has a 50-fold greater steroid-binding capacity but a 7.5-fold lower affinity than its parent fusion protein. In addition, the 22-kDa immunoreactive polypeptide released from SHBG(1-194) binds steroid, and its dimerization is promoted by steroid ligands that bind SHBG with high affinity. These data suggest that the N-terminal region of SHBG dimerizes readily in the absence of GST and in doing so acquires steroid-binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1995

Transient local presence of nerve fibers at onset of secondary ossification in the rat knee joint.

In view of recent evidence that nerves may be involved in bone formation, the present study examines the local occurrence of axons at the onset of secondary ossification center formation in the knee region of developing rats. Radiographic and histological examination showed that secondary ossification center formation commenced at day 10. At day 15 the epiphyseal ossification had reached a relatively mature state. As seen by light microscopy, cartilage canals first appeared at day 5, reaching the epiphyseal center by day 9. Axons exhibiting a neurofilament-like immunoreactivity emerged from the perichondrial plexa into the cartilage canals. Many calcitonin gene-related peptide (CGRP)-immunoreactive axons were found in the canals, as well as in the perichondrium. Axons with tyrosine hydroxylase-like immunoreactivity were not found in the canals, but such fibers occurred in relation to blood vessels at other sites. The canal-related axons disappeared between days 13 and 15, and the canals themselves did not persist beyond bone formation. As seen in the electron microscope, an individual canal contained 3-10 unmyelinated Schwann cell-enclosed axons with diameters of 0.1-2.0 microM. These observations show that putative sensory unmyelinated axons with CGRP-and SP-like immunoreactivity are transiently present during initiation of bone formation in developing epiphyses. Whether there is a causal relation between transient innervation and osteogenesis remains to be determined.

Animals↗