Tachycardia, hypertension and decreased reflex bradycardia produced by striatal lesions induced by kainic acid

The effects of intra-striatal injection of kainic acid on cardiovascular function were assessed in urethane-anesthetized rats. Intra-striatal administration of 2 micrograms of kainic acid (in a volume of 0.5 microliter) produced both tachycardia and hypertension. The tachycardia induced by intra-striatal injection of kainic acid was antagonized by either prior bilateral vagotomy or spinal transection of the animals (at C7). On the other hand, the hypertension induced by intra-striatal administration of kainic acid was antagonized by prior bilateral vagotomy, but not spinal transection. In addition, reflex bradycardia was produced by intravenous infusion of adrenaline in rats. Over the dose range (1.25-5.0 micrograms/kg, i.v.) of adrenaline used, a dose-dependent bradycardia was obtained. It was found that pretreatment of animals with intra-striatal injection of kainic acid, although causing no change in the adrenaline-induced pressor effect, did reduce the adrenaline-induced bradycardia. Intravenous administration of same dose of kainic acid had no effect on these cardiovascular responses. Thus, the data indicate that striatal neurones are involved in the central control of cardiovascular function.

Comparison of osteotomy healing under external fixation devices with different stiffness characteristics

The aim of this study was to investigate the effect of the rigidity of external fixation on osteotomy healing based on radiographic, morphological, histological, and biomechanical analyses of canine tibial osteotomies treated with more rigid (six half-pins) and less rigid (four half-pins) unilateral external fixators. Successful healing was obtained in all tibiae, but the bone-healing mechanisms appeared to be different depending on the rigidity of the device used. On the side with more rigid fixation, early clinical union was observed thirty days after osteotomy. Periosteal callus formation was significantly increased on the less rigidly fixed side at both ninety and 120 days (p less than 0.05). Fixation stiffness was found to affect the incidence of pin loosening (p less than 0.01) and of bone porosity (p less than 0.05) at the osteotomy site. However, new-bone formation and the structural strength of the bone were not significantly different between the four-pin and six-pin sides. These results seem to indicate that a longer period is required for fracture repair and remodeling when external fixation with less rigidity is used.

Cartilage type IX collagen is cross-linked by hydroxypyridinium residues

Type IX collagen, a recently discovered, unusual protein of cartilage, has a segmented triple-helical structure containing interchain disulfides. Its polymeric form and function are unknown. When prepared by pepsin from bovine articular cartilage, type IX collagen was found to contain a high concentration of hydroxypyridinium cross-links, similar to that in type II collagen. Fluorescence spectroscopy located the hydroxylysyl pyridinoline and lysyl pyridinoline cross-linking residues exclusively in the high-molecular-weight collagen fraction, from which they were recovered predominantly in a single CNBr-derived peptide. The results point to a structural role for type IX collagen in cartilage matrix, possibly as an adhesion material to type II collagen fibrils.

Administration of prostaglandin E2 into the striatum induces hyperthermia in rats

Changes in thermoregulatory function were assessed in unanesthetized rats after a unilateral injection of prostaglandin E2 (PGE2) into the striatum or the substantia nigra. Intrastriatal injection of PGE2, but not vehicle solution, induced a dose-dependent rise in rectal temperature. The hyperthermia in response to intrastriatal injection of PGE2 was due to increased metabolism and/or cutaneous vasoconstriction. Furthermore, the PGE2-induced hyperthermia was antagonized by prior intrastriatal injection of kainic acid (to destroy cell bodies in the striatum) but not by pretreatment with 6-hydroxydopamine (to destroy the dopaminergic nerve fibers in the striatum). On the other hand, administration of PGE2 into the substantia nigra induced no significant change in thermoregulatory functions. The data showed that PGE2, when injected into the striatum, may act on cell bodies in the striatum to induce hyperthermia by promoting an increase in heat production and/or vasoconstriction.

Identification of hydroxypyridinium cross-linking sites in type II collagen of bovine articular cartilage

In mature cartilage, collagen fibrils are strengthened by covalent intermolecular bonds provided by 3- hydroxypyridinium cross-linking residues. To determine the location of these trifunctional cross-links within the type II collagen molecule, CNBr peptides were analyzed from pepsin-soluble collagen and from guanidine hydrochloride insoluble collagen of bovine articular cartilage. The presence of hydroxypyridinium residues in collagen alpha chains and CNBr-derived peptides was detected by their characteristic natural fluorescence. Quantitatively, about one in three alpha chains from pepsin-soluble collagen was found to contain a hydroxypyridinium residue. Its distribution in the chains was limited to two CNBr peptides, which were purified by column chromatography on CM-cellulose and Bio-Gel P-30 followed by slab-gel electrophoresis in sodium dodecyl sulfate-polyacrylamide. The composition and properties of the two peptides indicated that the main component of one was alpha 1(II)- CB9 ,7 and of the other alpha 1(II) CB12 . It was suspected that two amino-terminal telopeptides were cross-linked by hydroxylysylpyridinoline to alpha 1(II) CB9 ,7 and two carboxy-terminal telopeptides to alpha 1(II) CB12 . The properties of fluorescent CNBr peptides isolated from digests of insoluble cartilage collagen supported this conclusion. Cleavage of the 3- hydroxypyridinium ring by UV light was exploited to confirm the identity of the cross-linked peptides. On UV irradiation, one cross-linked peptide released alpha 1(II) CB9 ,7, and the other, alpha 1(II) CB12 . The findings indicate there are only two hydroxypyridinium cross-linking sites within the triple-helical region of the type II collagen molecule, probably placed symmetrically at opposite ends at residues 87 and 930, where telopeptide aldehydes are known to react to form the initial "head to tail" intermolecular bonds.

All three chains of 1 alpha 2 alpha 3 alpha collagen from hyaline cartilage resist human collagenase

A previous report that the 3 alpha collagen chain of hyaline cartilage was cleaved by human collagenase could not be confirmed when the 1 alpha 2 alpha 3 alpha collagen fraction was freed of all contaminating type II collagen. All three minor collagen chains, 1 alpha, 2 alpha and 3 alpha, were totally resistant to highly purified collagenases from both rheumatoid synovial and gastric mucosal tissues. This finding and CNBr-peptide patterns suggest that, despite the close homology with alpha 1 (II), the 3 alpha chain is a unique collagen component, possibly combined with 1 alpha and 2 alpha in heterotrimeric molecules. In contrast, a 3 alpha-like component from fibrocartilage was cleaved by collagenase and gave a CNBr-peptide pattern more typical of alpha 1 (II) than of the collagenase-resistant 3 alpha of hyaline cartilage.

Effects of kainic acid injections in the striatum on physiologic and behavioral functions in conscious rats

Alterations in both physiologic and behavioral functions were assessed in unanesthetized rats after a unilateral injection of kainic acid (KA) in the striatum. The immediate behavioral effects were dyskinesias, head swaying, circling, tail elevation, hyperpnea and marked salivation. The induced behavioral responses lasted for about 14 to 18 h. Rats with intrastriatal KA injection, although showing no thermoregulatory deficit at both moderate (22 degrees C) and hot (30 degrees C) environmental temperatures, displayed a lower metabolism and a lower rectal temperature than the preinjection controls in the cold (8 degrees C) environment. In addition, the hypothermia induced by intrastriatal administration of apomorphine (dopamine agonist) was greatly antagonized by pretreatment with intrastriatal injection of KA. Furthermore, intrastriatal infusions of KA (1 microgram in 0.5 microliter) also caused a decrease in pain threshold (or in the latency to the hind-paw lick on the hot plate test), hypophagia, polydipsia, and weight loss. The induced alterations in thermoregulation, pain reflex, and ingestive behavior lasted for about 7 days. These data indicate that striatal neurons are involved in the central control of motor activity, thermoregulation, the pain reflex, and ingestive behavior.

Collagen of fibrocartilage: a distinctive molecular phenotype in bovine meniscus

Fibrocartilage of bovine knee meniscus was analyzed for major and minor collagen constituents. The main fraction (approximately 98%) of pepsin-solubilized collagen consisted of type I with a small proportion (less than 10%) of type III molecules. The minor fraction (1--2%) isolated by salt precipitation could be further resolved into type V collagen that consisted of alpha 1(V) and alpha 2(V) chains and a type II-like molecule with chains that had all the characteristics of the 3 alpha variant of alpha 1(II) found in hyaline cartilage. The articular surface zone of the meniscus appeared 2--3-fold enriched in these minor collagens compared with deeper tissue, though qualitatively the same distinctive collagen phenotype was evident throughout.

Serotonergic mechanisms in the hypothalamus mediate thermoregulatory responses in rats

1. Either electrical stimulation of midbrain raphe nuclei or administration of 5-hydroxytryptamine (5-HT; serotonin) into the preoptic anterior hypothalamus caused hypothermia in conscious rats at ambient temperatures (Ta) of both 8 degrees C and 22 degrees C. The hypothermia was due to decreased metabolic heat production at Ta = 8 degrees C, while at Ta = 22 degrees C the hypothermia was due to both decreased metabolism and increased heat loss (cutaneous vasodilatation). However, at Ta = 30 degrees C, electrical stimulation of midbrain raphe or intrahypothalamic injection of 5-HT caused an insignificant change in the thermoregulatory responses. There was no changes in respiratory evaporative heat loss in response to these treatments at various Ta's. 2. Direct administration of the serotonergic receptor antagonists such as cyproheptadine and methysergide into the preoptic anterior hypothalamus caused hyperthermia in conscious rats at Ta's of 8 degrees C, 22 degrees C and 30 degrees C. The hyperthermia was due to increased metabolism and cutaneous vasoconstriction. 3. The hypothermia induced by intrahypothalamic administration of 5-HT was antagonized by pretreatment with an intrahypothalamic dose of either cyproheptadine or methysergide in rats at Ta = 22 degrees C. 4. Inhibition of 5-HT neuronal activity with administration of 5-HT into the midbrain raphe regions also caused hyperthermia, increased metabolism and cutaneous vasoconstriction in rats at Ta's of 8 degrees C, 22 degrees C and 30 degrees C. 5. These observations tend to suggest that the functional activity of serotonergic receptors in the preoptic anterior hypothalamus mediates thermoregulatory responses in the rat. Activation of serotonergic receptors in the hypothalamus decreases heat production and/or increases heat loss, while inhibition of serotonergic receptors in the hypothalamus increases heat production and/or decreases heat loss in the rat.

Autonomic dysfunction in palmar hyperhidrosis

The autonomic (including sudomotor, baroreceptor, and vasomotor) functions were assessed in 3 groups of individuals, comprising normal, hyperhidrotic, and denervated subjects. The normal group had no palmar hyperhidrosis, with intact T2-3 ganglia, the hyperhidrotic group had palmar hyperhidrosis with intact T2-3 ganglia, and the denervated group had palmar hyperhidrosis treated with T2-3 ganglionectomy. Compared with both the normal and hyperhidrotic subjects, the denervated subjects had a much smaller sweating response of both the forehead, the upper chest region and the upper extremities, and a much greater sweating response of both the lateral lumbar and ventral thigh regions in response to body exercise. In addition, cardiovascular responses to either the Valsalva manoeuver, face immersion, or finger immersion were evaluated in these groups of subjects. When compared with those of either the normal or the denervated subjects, the hyperhidrotic subjects had less reflex bradycardia in response to either Valsalva manoeuver or face immersion. In contrast, when compared with those of either the normal or the denervated subjects, the hyperhidrotic subjects had a higher degree of cutaneous vasoconstriction in response to finger (or cold) immersion. The data indicate that the sympathetic fibers passing through the T2-3 ganglia play an important role in the elaboration or modulation of autonomic function elsewhere. Probably, the hyperhidrotic subjects have an over-functioning of the sympathetic nervous fibers which pass through the T2-3 ganglia, which leads to autonomic dysfunction. The autonomic dysfunctions observed in the hyperhidrotic subjects could be eliminated after the interruption of the excessive sympathetic activities passing through the T2-3 ganglia level. A preliminary report of this work was delivered at the 15th Congress of the Pan-Pacific Surgical Association, January 12-18, 1980 and the 12th World Congress of Neurology, September 20-25, 1981.

A norepinephrine-cyclic AMP link in the hypothalamic pathways which mediate fever induced by endotoxin and prostaglandin E2 in the rat

The changes in rectal temperature, metabolic rate, cutaneous temperatures and respiratory evaporative heat loss produced by an injection of a bacterial endotoxin piromen (4-40 ng in 1 microliter) into the anterior hypothalamus were assessed in conscious rats in both sexes from a wide range of body mass and at various ambient temperatures (TaS). Intrahypothalamic injection of piromen increased metabolism and decreased cutaneous temperatures which led to fever in rats at Ta 8-30 degrees C. The monophasic fever was not significantly correlated with either body mass, sex difference of the Ta at which the experiments are carried out. Furthermore, daily intrahypothalamic injections of piromen produced no pyrogenic tolerance. Intrahypothalamic injections of either prostaglandin E2, norepinephrine, aminophylline or dibutyryl cyclic AMP also produced increased metabolism and decreased cutaneous temperature which led to fever at Ta 8-30 degrees C. In addition, the fever induced by intrahypothalamic injections of piromen, prostaglandin E2 or nor-epinephrine was greatly antagonized by pretreatment with intrahypothalamic injections of alpha or beta adrenergic antagonist. However, the fever induced by dibutyryl cyclic AMP or aminophylline was not affected by pretreatment with adrenergic receptor blockade. The data indicate that a norepinephrine- cyclic AMP link occurs in the hypothalamic pathways which mediate the piromen-induced or the prostaglandin E2-induced fever in rats.

Activation of striatal dopamine receptors induces pain inhibition in rats

In the rat, elevating dopamine content in corpus striatum with electrical stimulation of substantia nigra or direct administration of apomorphine (50-200 micrograms) into the lateral cerebral ventricle or apomorphine (2-10 microgram) into the caudate-putamen complex decreased pain sensitivity (as shown by an increase in the latency to hind-paw lick in the hot plate test). Furthermore, the decreased pain sensitivity after the central administration of apomorphine was antagonized by pretreatment with haloperidol (a dopamine antagonist). On the other hand, lowering dopamine content in corpus striatum with electrolytic destruction of substantia nigra and 6-hydroxydopamine lesions to the substantia nigra, as well as direct injection of haloperidol into the lateral cerebral ventricle or caudate-putamen complex increased pain sensitivity. The data indicate that activation of striatal dopamine receptors in rat brain induces pain inhibition.

Serotypes and biotypes and antibiotic susceptibility of Haemophilus influenzae encountered in a clinical laboratory in Taiwan

Forty-four serologically and biochemically typable Haemophilus influenzae isolates from clinical specimens in Taiwan were subjected to analysis in their relationship with source of isolation and age distribution. It was found that all isolates from blood and cerebrospinal fluid were serotype b, biotype I, and all were in children less than 4 years of age. Serotypes b and e, biotypes I and III were encountered to have the highest incidence of infection caused by H. influenzae in this area. All H. influenzae isolates were further tested for susceptibility to several selected antibiotics. All strains of this organism were susceptible to erythromycin and chloramphenicol. All but two strains were susceptible to tetracycline, whereas more strains were resistant to carbenicillin, gentamycin, keflin, and penicillin. Thirty-four percent strains were found to be resistant to ampicillin and all were beta-lactamase producer. No direct correlation between ampicillin resistance and serotypes or biotypes was recognized.