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Biomedical subjects

A Car

Publications and source records attributed to A Car.

At least 19 recordsLinked to original sources
PubMed2003

Serum sialic acid in subjects with impaired glucose tolerance and in newly diagnosed type 2 diabetic patients.

Several general population studies and those carried out in diabetic patients with complications have pointed to serum sialic acid as a marker of inflammation in atherosclerosis. In this study we examined whether total sialic acid (TSA) was changed in the sera of 28 newly diagnosed subjects with type 2 diabetes (type 2 DM), 47 subjects with impaired glucose tolerance (IGT) and 72 subjects with normal glucose tolerance (NGT). The associations between sialic acid and other atherosclerotic risk factors such as lipid profile, baseline diene conjugates in low-density lipoproteins (LDL-BDC) and fasting insulin were also investigated. We found a trend to TSA increase in subjects with impaired glucose tolerance and a significant increase in TSA in newly diagnosed patients with type 2 DM (2.2+/-0.3 vs. 1.9+/-0.3 mmol/l; p<0.03) when compared to subjects with NGT. Lipid profile and LDL-BDC, as a marker of circulating oxidized LDL, did not differ among glucose tolerance categories. Significant associations between total sialic acid and 2-h post-load glucose level, fasting insulin, insulin sensitivity, HDL-cholesterol and log of triglycerides were found in the examined subjects. Multiple regression analysis showed significant correlations between serum sialic acid and 2-h post-load glucose levels and insulin sensitivity. This study indicates that measurement of TSA as a marker of subclinical inflammation may be valuable as an independent parameter in identifying subjects at higher risk of developing type 2 diabetes and those who might benefit from anti-inflammatory treatment.

Biomarkers↗
PubMed2002

Baseline diene conjugation in LDL lipids from newly diagnosed type 2 diabetic patients.

BACKGROUND: To determine whether the susceptibility of low-density lipoproteins (LDL) to oxidation was altered in subjects with newly diagnosed type 2 diabetes mellitus and impaired glucose tolerance using the measurement of LDL baseline diene conjugation (LDL-BDC) as an indicator of circulating mildly oxidized LDL in vivo. METHODS: LDL was isolated from sera of 26 newly diagnosed patients with type 2 diabetes mellitus (type 2 DM), 43 subjects with impaired glucose tolerance (IGT), and 67 subjects with normal glucose tolerance (NGT), who were matched for age, gender, body mass index and serum lipids. Twenty-seven healthy subjects with normal body mass index and normal values of lipids served as a control group. In all groups the LDL-BDC was compared with the production of conjugated dienes after copper-induced LDL oxidation, and with total antioxidative status. RESULTS: The LDL-BDC levels (micromol/l; mean +/- SD) were similar in the three glucose tolerance categories (NGT 66.5 +/- 6.9; IGT 67.9 +/- 6.5; type 2 DM, 68.1 +/- 7.1 p = 0.52) and there was no difference in comparison with the control group (68.9 +/- 4.2 micromol/l). Also, no significant differences between the groups were observed in the susceptibility to LDL oxidation in vitro or total antioxidative status. There was no correlation between glycemia and mildly oxidized LDL in vivo, nor with any of the parameters of the LDL oxidation in vitro. CONCLUSIONS: In the examined population of newly diagnosed diabetic patients with mild hyperglycemia, as evidenced by the level of glycated haemoglobin (HbA(1C)), a lack of changes in the susceptibility of LDL to oxidation both in vivo and in vitro was established.

Antioxidants↗
PubMed2000

Effects of lingual nerve afferents on swallowing in sheep.

We investigated in sheep the effects of stimulation of the thick afferent fibers running through the lingual nerve (LN) upon the activity of some of the muscles and medullary interneurons or motoneurons which are active during swallowing. Using electromyography (EMG), and extra- and intracellular neuronal recording, we demonstrated that LN stimulation inhibited triggering and/or distal progression of deglutition reflexly induced by stimulation of the superior laryngeal nerve (SLN). This inhibition appeared as a delay, or the interruption or total suppression, of the EMG and neuronal swallowing activities, depending on the interval between SLN and LN stimulation. It was apparent at the level of the muscles and motoneurons of the nucleus ambiguus, as well as at the level of the interneurons of the dorsal medulla within or around the nucleus of solitary tract, which are assumed to be the core of the organizing system for swallowing, the so-called central pattern generator (CPG). Taking into account the stimulation parameters used in our experiments, it was likely that only LN-mechanosensitive fibers were excited. These fibers were involved in the jaw-opening reflex, and possibly in mastication regulation. Therefore, inhibition of swallowing could result from interactions between the hindbrain mastication and swallowing CPGs. However, it was also possible that mechanosensitive afferents acted upon the swallowing CPG directly or indirectly through supramedullary, especially cortical, loops.

Afferent Pathways↗
PubMed2000

In vitro effect of zinc on superoxide anion production by polymorphonuclear leukocytes of diabetic patients.

We evaluated the ability of zinc to modulate the superoxide anion released by isolated, phorbol myristate acetate (PMA)-stimulated polymorphonuclear leukocytes (PMNs). In the presence of zinc at physiological level (20 micromol/l), PMNs released 20% less superoxide anions than untreated cells, whereas at higher zinc concentration (200 micromol/l), a 40%-increase in superoxide anion production was detected. The direction (suppression or stimulation) of superoxide anion generation was dependent upon extracellular zinc level and did not discriminate type 1 and 2 diabetic subjects from normal controls. The mechanism(s) of dose-dependent pro- and antioxidative effects of zinc on isolated PMNs in vitro as well as the implication of this finding for the modulatory effect of Zn on PMN-superoxide anion production in vivo need further investigation.

Adult↗
PubMed2000

[Choledochal cysts: surgical treatment].

The excision of the choledochal cyst with bile drainage through intestinal conduit is a standard operative procedure in the surgical management of choledochal cysts. During the last eight years five patients have been treated with this operation at the University Children's Hospital in Zagreb. All the patients were girls aged from two months to twelve years. The classical triad of pain, jaundice and abdominal mass was observed in only one patient, an eight-year-old girl. The only symptom in infancy was jaundice. Diagnosis was made by abdominal ultrasound, bibliography, CT scan with hepatotropic contrast and in older children by ERCP. Four cysts were type Todani I, and one cyst was Todani type II. The complete excision of the choledochal cyst with the Roux-Y jejunal conduit without antireflux valve was performed. There was neither operative morbidity nor mortality. Three months postoperatively the control ultrasonography and liver laboratory tests were without abnormalities. The routine control which followed did not show episodes of cholangitis, lithiasis, lipid malabsorption, blood clotting abnormalities or growth failure. The complete excision of the cyst with Roux-Y hepaticoenterostomy is an operative treatment with good results in infancy and childhood.

Child↗
PubMed1999

Stimulation of the chewing area of the cerebral cortex induces inhibitory effects upon swallowing in sheep.

Mastication and swallowing are two tightly integrated components of food intake behavior. We investigated the effects of stimulating the chewing area of the fronto-orbital cortex (CCx) on some muscles and medullary interneurons (Ins) or motoneurons (Mns) active during swallowing. For the purpose of comparison, the lingual nerve (LN) was also stimulated during the experiments. Electromyography (EMG) and extracellular neuronal recording were used, and swallowing was reflexly induced (RIS) by stimulation of the superior laryngeal nerve (SLN). RIS was almost totally abolished during long-lasting repetitive stimulation of CCx or LN, and was strongly facilitated after stimulation cessation. Short-duration stimulation (one or a few pulses) of both the CCx and LN also inhibited triggering of deglutition when delivered just before the onset of RIS. This inhibition appeared as a delay or total suppression of the EMG and neuronal swallowing activities. It was obvious at the level of the muscles, the hypoglossal Mns and the premotoneurons (PMns; Ins of the ventral medulla near the nucleus ambiguus), as well as at the level of the Ins of the dorsal medulla (within or around the solitary tract nucleus) which are assumed to be the core of the 'central pattern generator' (CPG) for swallowing. In addition to the 'chewing-related inhibition', many ventral Ins exhibited a short latency synaptic activation after CCx and/or LN stimulation. Therefore, these Ins may play a pivotal role for reflex or cortical fast control of tongue (and jaw) muscles, and for coordinating their contractions in the context of mastication-deglutition interactions.

Animals↗
PubMed1998

[Deglutition: physiologic and neurophysiologic aspects].

Swallowing is a complex motor sequence involving the coordinated contraction of many muscles of the buccopharyngeal cavity, the larynx and the oesophagus. Most of the muscles are striated except those of the distal oesophagus which, in human and some other species, are of the smooth type. During swallowing, usually divided into a buccopharyngeal and an oesophageal stage (peristalsis), the sequential activity of the muscles results from motor orders programmed by a rhombencephalic swallowing centre and conveyed to the periphery by efferent fibres belonging to various pairs of cranial nerves (Vth, VIIth, Xth, XIIth). Apart from the motor nuclei of the cranial nerves, the swallowing centre contains an interneurone network responsible for the programming of deglutition. During swallowing, these interneurones (INs) exhibit a sequential activity quite parallel to that of muscles, and persisting in the absence of sensory feedback. The "swallowing INs" are located in two medullary regions: (1) a dorsal region including the nucleus of the solitary tract and the adjacent reticular formation, (2) a ventral region corresponding to the reticular formation surrounding the nucleus ambiguus. The dorsal INs are involved in the initiation and the programming of swallowing. The ventral INs receive their swallowing input from the dorsal neurones and are probably switching neurones that distribute the swallowing excitation to the various pools of motoneurones. The swallowing program can be triggered by inputs originating from either the peripheral reflexogenic areas or the supramedullary structures (cerebral cortex, basal ganglia and hypothalamus). Under physiological circumstances swallowing program is continuously modified by peripheral afferents (expecially muscular) that adjust the force and the timming of contractions to the size of the swallowed bolus. In addition, an important operating feature of the programming network consists of a functionnal polarization so that the activity of proximal portions of the swallowing tract inhibits that of distal portions. This polarization implies the existence of inhibitory connections between interneurones, that could be responsible for the series of delays typical fo swallowing contractile sequence, by generating delayed desinhibitions followed by post inhibitory excitations. Lastly, the sensitive messages that trigger and adjust the swallowing program are at the same time conveyed to higher nervous structures allowing the so called "voluntary" swallow and the integration of swallowing in the ingestive behavior. Disruption of this central loop is likely the source of swallowing disorders (dysphagia) following lesion of cortical or subcortical structures.

Animals↗
PubMed1997

Intracellular activity of motoneurons of the rostral nucleus ambiguus during swallowing in sheep.

The nervous mechanisms that generate swallowing are still largely unknown. It has been suggested that a central pattern generator that contains a serial network of linked neurons must produce the successive excitation of motoneurons (Mns) and then the sequential activation of muscle through excitatory connections. Inhibitory connections have also been envisioned but never evidenced at the membrane level of the swallowing neurons. We investigated, by intracellular recordings, the behavior of 96 Mns in the rostral nucleus ambiguus during swallowing induced by application of superior laryngeal nerve stimulation to anesthetized sheep. The Mns were identified by antidromic activation following stimulation of glossopharyngeal, pharyngoesophageal, or cervical vagal nerves. Nine Mns showed a bell-shaped depolarization during the buccal or the early pharyngeal stage of swallowing. They probably projected to muscles of the soft palate (palatopharyngeal) and upper pharynx (stylopharyngeal, hyopharyngeal). Thirty-eight Mns exhibited a chloride-dependent hyperpolarization, indicating that they were under an active inhibition throughout the buccopharyngeal stage of swallowing. These Mns constitute a heterogeneous pool: some of them, producing spontaneous inspiratory discharges, probably innervated laryngeal or pharyngeal muscles; others might also be Mns of the esophagus, whose swallowing pattern was modified because of the anesthesia (suppression of the esophageal peristalsis). Forty-nine Mns showed a chloride-dependent hyperpolarization with a variable duration at the onset of swallowing, followed by a depolarization that could take place during either the buccopharyngeal (HD1-Mns) or the esophageal (HD2- and HD3-Mns) stage of deglutition. HD1-Mns probably projected to the median and inferior constrictors of the pharynx. HD2-Mns produced depolarizations with longer latencies and durations than those of the HD1-Mns. They probably projected to either the superior esophageal sphincter or the cervical esophagus (CE). HD3-Mns showed a buccopharyngeal hyperpolarization that was followed first by a lower-amplitude hyperpolarization accompanying the proximal CE contraction and then by a delayed depolarization. These Mns probably innervated the inferior CE or thoracic esophagus. We conclude that the initial inhibition exerted on the HD-Mns, by delaying the excitation of Mns, may play a role in the nervous mechanisms involved in temporal organization of the swallowing motor sequence. We suggest that swallowing disorders in humans such as dysphagia by failure of cricopharyngeal relaxation, diffuse esophageal spasm, and achalasia might be caused by impaired inhibitory mechanisms.

Animals↗
PubMed1992

[Phagocytic activity in rheumatoid arthritis].

The phagocytic activity of leukocytes was studied in 41 patients with active rheumatoid arthritis, 24 of whom were treated with gold compounds and the remaining 17 with non-steroidal anti-inflammatory drugs. The control group comprised 137 patients with no signs of inflammatory rheumatic diseases. The mean age of patients was 54.8 years (range: 32-75) and that of the controls, 53.5 years (range: 32-75). Spontaneous mobility (P < 0.001), phagocytic activity (P < 0.001) and antibody-dependent cytotoxicity (P < 0.001) of leukocytes were significantly lower in patients with rheumatoid arthritis compared to the control group. No significant differences were observed between patients treated with gold compounds and those receiving nonsteroidal anti-inflammatory drugs with respect to mean spontaneous mobility (U = 198, P = 0.44), phagocytic activity (U = 185, P = 0.31) and antibody-dependent cytotoxicity (U = 183, P = 0.29) of leukocytes. Among patients treated with gold compounds phagocytic activity was significantly lower in those receiving TauredonR compared to those receiving AuropanR (U = 33.5, P = 0.05). The antibody-dependent cytotoxicity was comparable in patients receiving Tauredon and Auropan, respectively (U = 58.5, P = 0.48).

Adult↗
PubMed1991

Effects of lingual nerve and chewing cortex stimulation upon activity of the swallowing neurons located in the region of the hypoglossal motor nucleus.

This study focuses on motoneurons and interneurons in the region of the hypoglossal nucleus (XIIth) related to swallowing and chewing. In sheep anesthetized with halothane, we have used extracellular microelectrodes to study the effects of stimulation of the superior laryngeal nerve (SLN), the lingual nerve (LN) and the chewing cortex (CCx) upon activities of the swallowing neurons (SNs). Ipsilateral stimulation (1-5 pulses at 500 Hz) of the peripheral afferents or CCx did not generally induce a short latency activation of the hypoglossal swallowing motoneurons (Group I SNs) since only 4 motoneurons (69 tested) were activated by the SLN, 4 motoneurons (56 tested) by the LN and none by the CCx. In contrast, the same stimulations were more effective with swallowing interneurons (Group II SNs) located in the reticular formation close to the XIIth motor nucleus since 12 neurons (30 tested) were activated with short latencies (9 +/- 1.8 ms; mean latency +/- S.D.) by the SLN, 9 neurons (21 tested) by the LN (latency; 8 +/- 1.8 ms) and 5 neurons (18 tested) by the CCx (latency: 13 +/- 1.7 ms). Seven neurons were activated by two or three modes of stimulation indicating the existence of convergent inputs upon some Group II SNs. During chewing movements induced by a prolonged stimulation (20-40 Hz) of the CCx, 10 Group I SNs (16 tested) versus only one Group II SN (8 tested) were found to fire in association with the jaw opening. Moreover, 3 motoneurons and 4 interneurons inactive during swallowing discharged during chewing movements.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1990

Axonal branching of medullary swallowing neurons projecting on the trigeminal and hypoglossal motor nuclei: demonstration by electrophysiological and fluorescent double labeling techniques.

The projections of ventral medullary reticular neurons on both trigeminal (Vth) and hypoglossal (XIIth) motor nucleus were studied in sheep anesthetized with halothane. In a first series of experiments, extracellular microelectrodes were used to record the activity of medullary swallowing interneurons (SINs) located in the ventral region (around the nucleus ambiguus) of the swallowing center. Antidromic activation after electrical stimulation of the Vth and XIIth nuclei was tested in 83 SINs. For 38 SINs a clear antidromic activation was observed and for 8 of them the response was triggered by stimulation of either nucleus. As confirmed by the reciprocal collision test, these 8 SINs had branched axons sending information to both nuclei tested. Average latencies for antidromic activation of branched SINs after stimulation of the XIIth and the Vth motor nucleus were 2.2 +/- 0.6 ms and 2.7 +/- 0.8 ms respectively. The axonal conduction velocity of these neurons was 4.4 +/- 1.3 m/s for the collateral to the Vth motor nucleus and 2.7 +/- 0.7 m/s for axons projecting to the XIith motor nucleus. In a second series of experiments the double retrograde labeling technique was used to confirm the existence of neurons with branched axons in the medullary regions corresponding to the swallowing center. Small and well localized injections of Fast Blue (FB) and Diamidino Yellow (DY) fluorescent tracers were made in the Vth and in the XIIth motor nucleus respectively. A relatively large number of double-labeled cells was found in the ventral region of swallowing center (reticular formation around the nucleus ambiguus, 2-4 mm in front of obex).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Activity of extrinsic tongue muscles during swallowing in sheep.

The participation of extrinsic muscles of the tongue in swallowing reflexly induced by stimulation of the superior laryngeal nerve was studied in 7 anesthetized sheep. The tongue retractor muscles (styloglossus and hyoglossus) always discharged in synergy with the suprahyoid (geniohyoid) and jaw (anterior digastric and medial pterygoid) muscles. The main protrusor muscle of the tongue, the genioglossus, was inactive in 5 animals and active in 2. The significance of this muscular synergy is discussed.

Animals↗
PubMed1988

Projections from the medullary swallowing center to the hypoglossal motor nucleus: a neuroanatomical and electrophysiological study in sheep.

Neurons of the hypoglossal (XIIth) motor nucleus participate in swallowing, but nothing is known of the input to these cells from swallowing interneurons (SIN) belonging to the medullary swallowing center (SC). After electrophoretic injection of horseradish peroxidase within the XIIth motor nucleus in sheep, labeled neurons were found principally in the ipsilateral ventrolateral reticular formation, 1-4 mm rostral to the obex which corresponds to the ventral region of the SC. Labeled cells were observed in the region of the nucleus of the tractus solitarius (dorsal region of the SC), predominantly when the injection site of HRP extended beyond the XIIth nucleus. The projections of ventral SIN to the XIIth nucleus was confirmed electrophysiologically. Twenty-seven of 98 tested SIN were antidromically activated (latency: 2.7 +/- 1.5 ms) by stimulating the XIIth nucleus. Twenty-one of these were histologically localized in the ventral SC, and only one in the dorsal SC. The other 5 SIN were located in the ventral group according to their stereotaxic coordinates. Our data show that SIN in the ventral reticular formation, part of the medullary SC, project to the XIIth motor nucleus; we suggest that ventral SIN are command interneurons for the different pools of motoneurons involved in swallowing.

Action Potentials↗
PubMed1987

Activity of neurons located in the region of the hypoglossal motor nucleus during swallowing in sheep.

Extracellular activity of swallowing neurons (SN) in the region of the hypoglossal (XIIth) motor nucleus was studied in sheep anesthetized with halothane. Eighty six SN exhibited a discharge closely linked to swallowing electromyographic (EMG) activity of the geniohyoïd (GH) muscle induced by stimulation of the superior laryngeal nerve. Swallowing activation persisted after motor paralysis, indicating that this activity did not result from sensory feedback. SN were classified into two groups. Group I SN (N = 66) discharged a burst of up to 12 spikes for 50-300 ms during the response of GH. Mean frequencies ranged from 10 to 60 Hz, peak instantaneous frequencies from 10 to 100 Hz. Thirty two SN were antidromically activated by stimulating the XIIth nerve. Mean latencies of antidromic spikes were 2.6 ms and 2.4 ms for SN sending their axons in the medial and lateral branches respectively of XIIth nerve, corresponding to conduction velocities of 50.4 m/s and 53.7 m/s. The other 34 group I SN were located at sites with large antidromic field potentials obscuring the identification of unitary antidromic spikes. Thirty group I SN, 16 antidromically activated and 14 in areas with large field potentials, were histologically located in the XIIth motor nucleus between the transverse planes 1 mm caudal to 2 mm rostral to the obex. Group I SN are likely motoneurons supplying GH and tongue musculature. Group II SN (N = 20) were never antidromically activated by XIIth nerve stimulation, and were all located in the reticular formation adjacent to the lateral edge of the XIIth motor nucleus, particularly in transverse planes within 1 mm of the obex.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1984

Medullary control of the pontine swallowing neurones in sheep.

The origin of the inputs from the medullary swallowing centre (dorsal region including the nucleus of the solitary tract, or ventral region corresponding to the reticular formation surrounding the nucleus ambigous) to the pontine swallowing neurones (PSNs) was studied in sheep anaesthetized with halothane. Out of 101 PSNs located in the posterior part of the trigeminal (Vth) motor nucleus, 46 were activated by stimulating either the dorsal (21 neurones) or the ventral (25 neurones) region of the ipsilateral medullary swallowing centre, 3-4 mm rostral from the obex. Thirty-one neurones out of the 46 were identified as alpha motoneurones supplying swallowing muscles (mylohyoïd, anterior body of digastric and medial pterygoïd). Their average activation latency through stimulation of the dorsal medullary region was about 1 ms longer than through stimulation of the ventral region (3.63 ms +/- 0.81 versus 2.72 ms +/- 0.32). To determine the origin of the medullary input to the PSNs, we tried to activate the medullary swallowing neurones (MSNs) antidromically through stimulating the posterior part of the Vth motor nucleus, which contains the swallowing motoneurones. Seventy-three MSNs were tested (25 located in the dorsal and 48 in the ventral region). None of the dorsal neurones tested could be antidromically activated by pontine stimulation: 15 ventral neurones showed a clear antidromic response (collision test) with an average latency of 2.5 ms +/- 0.73. These neurones, which send their axons into the pons, were all located in the reticular formation, above the nucleus ambiguus, 3-4 mm rostral from the obex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗