Biomedical subjects

Carole Mathis

Publications and source records attributed to Carole Mathis.

5 recordsLinked to original sources

PubMed2004

The treatment of diabetic gastroparesis with botulinum toxin injection of the pylorus.

OBJECTIVE: Gastroparesis is a disorder of delayed gastric emptying that is often chronic in nature. Up to 50% of type 1 diabetic subjects have symptoms of gastroparesis, which include nausea, vomiting, and early satiety. Elevated pyloric pressures may be responsible for delayed gastric emptying in diabetic subjects. Botulinum toxin inhibits the release of acetylcholine and produces transient paralysis when injected into smooth muscle. The aim of this study was to determine whether injection of the pylorus with botulinum toxin in patients with diabetic gastroparesis improves symptoms of gastroparesis, alters gastric emptying scan time, and/or changes weight and insulin use. RESEARCH DESIGN AND METHODS: This was an open-label trial with age- and sex-matched control subjects from a tertiary care referral center for patients with gastroparesis. Eight type 1 diabetic subjects (six women and two men; mean age 41 years; mean years with diabetes 25.3) who had failed standard therapy were enrolled. Intervention consisted of injection of the pylorus with 200 units of botulinum toxin during upper endoscopy. Symptoms, antropyloric manometry, gastric emptying scan times, weight, and insulin use were all recorded before intervention and during a 12-week follow-up period. RESULTS: Seven of the eight patients completed the full 12-week follow-up period. No complications were noted. Mean symptom scores declined from 27 to 12.1 (P < 0.01), whereas the SF-36 physical functioning domain also improved (P < 0.05). Four patients noted an increase in insulin use of >5 units/day. Six of the seven patients gained weight (P = 0.05). Gastric emptying scan time improved in four patients. CONCLUSIONS: Botulinum toxin injection of the pylorus is safe and improves symptoms in patients with diabetic gastroparesis. These results warrant further investigation with a large, double-blind, placebo-controlled trial.

Adult↗

PubMed2003

Motor training compensates for cerebellar dysfunctions caused by oligodendrocyte ablation.

The role played by oligodendrocytes (OLs), the myelinating cells of the CNS, during brain development has not been fully explored. We have addressed this question by inducing a temporal and reversible ablation of OLs on postnatal CNS development. OL ablation in newborn mice leads to a profound alteration in the structure of the cerebellar cortex, which can be progressively rescued by newly generated cells, leading to a delayed myelination. Nevertheless, the temporal shift of the OL proliferation and myelinating program cannot completely compensate for developmental defects, resulting in impaired motor functions in the adult. Strikingly, we show that, despite these abnormalities, epigenetic factors, such as motor training, are able to fully rescue cerebellar-directed motor skills.

Animals↗

PubMed2003

Oligodendrocyte ablation impairs cerebellum development.

Oligodendrocytes (OLs) are the glial cells of the central nervous system and are classically known to form myelin sheaths around most axons of higher vertebrates. Whether these cells might have other roles, in particular during development, has not been studied. Taking advantage of a transgenic mouse model in which OLs can be selectively killed in a desired time-frame, we have investigated the impact of OL ablation on cerebellar development. OL ablation was induced during the first 3 postnatal weeks, a time at which cerebellum development is ongoing. Strikingly, OL ablation triggers a profound perturbation of the known cerebellum developmental program, characterized by the disorganization of the cortical layers, abnormal foliation and a complete alteration of Purkinje cell dendritic arborization and axonal fasciculation. This phenotype is accompanied by decreased granule cell density, a disorganized Bergmann glia network and impaired migration of interneurons in the molecular layer. These results demonstrate a previously ignored role of OLs in the formation of the cerebellar cytoarchitecture.

Animals↗

PubMed2002

Control of lactotrop proliferation by dopamine: essential role of signaling through D2 receptors and ERKs.

Dopamine is thought to exert a negative control on lactotrop cell proliferation and prolactin production. Indeed, mice lacking the D2 receptor develop pituitary tumors of lactotrop origin. Because lactotrops express two isoforms of D2R, D2L, and D2S, in a specific ratio, we decided to explore the physiological importance of their relative abundance in vivo. Thus, we generated transgenic animals overexpressing either D2L or D2S in lactotrops. Increased expression of D2S, but not of D2L, leads to mitogen-activated protein kinase (MAPK) induction, which results in pituitary hypoplasia. On the other hand, levels of phosphorylated MAPKs are drastically reduced in pituitary tumors generated by the absence of D2-dependent signaling. These results underline a critical role of D2-mediated MAPK activation in lactotrop proliferation. Furthermore, whereas D2S overexpression results to a drastic reduction of prolactin, D2L overexpression elevates it. Our findings underscore a different role of the two D2R isoforms in the pituitary gland physiology.

Animals↗

PubMed2002

Influences of pelvic floor structures and sacral innervation on the response to distension of the cat rectum.

The contributions to the rectal response to distension of the pelvic floor structures surrounding the rectum and of the sacral spinal innervation have never been studied. Using paralysed intercollicularly decerebrate, anaesthesia-free cats, we studied pressure-volume relationships during slow ramp distensions of the rectum. Results obtained from animals with intact pelvic cavities were compared with those following mobilization of the rectum from the pelvic floor musculature. To assess the influences of spinal outflow and afferent input, rectal pressure-volume relationships were measured in the mobilized rectum following bilateral sequential transection of the spinal roots S1 to S3, first dorsal, then ventral. Isolation of the rectum from the pelvic floor structures resulted in a decrease in balloon volume in the lower range of distension pressure but did not affect volumes at higher pressures. The only afferent effect was seen after sectioning of dorsal roots S1, which resulted in a decrease in balloon volume. The only efferent effect was seen after sectioning of ventral roots S3, which decreased balloon volume further. In conclusion, the rectal response to distension depends on the properties of the rectal wall. It may be influenced by somatic inputs, inputs from the myenteric nervous plexus, and from the parasympathetic and sympathetic nervous systems. Afferent inputs and spinal autonomic reflexes may decrease the tone of the rectal musculature during distension.

Animals↗