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Biomedical subjects

L Carrier

Publications and source records attributed to L Carrier.

At least 73 records · Page 4Linked to original sources
PubMed1989

G-protein dependent potentiation of calcium release from sarcoplasmic reticulum of skeletal muscle.

Skinned fibre experiments were conducted to determine if guanine nucleotide-binding proteins play a role in excitation-contraction coupling of skeletal muscle. By itself, the GTP-gamma S, a non hydrolysable GTP analogue was unable to induce calcium release from the sarcoplasmic reticulum, even at concentrations as high as 500 microM. However, calcium- or caffeine-induced calcium releases were enhanced by GTP-gamma S in micromolar concentrations. This response was blocked by GDP-beta S or Pertussis toxin. 32P-ADP-ribosylation catalysed by Pertussis toxin, radiolabelled G-protein alpha subunits in the range of 40 kDa on membrane subcellular fractions of rat skeletal muscle. Using Western blot analysis with antibodies raised against the bovine transducin, G-proteins were identified in frog and rat skeletal muscle subcellular fractions. In most of the muscle fractions (plasma membrane, T-tubules, triads, sarcoplasmic reticulum), the anti-beta subunit antibodies recognized a 36 kDa protein which comigrated with transducin beta subunit. It appears therefore that some of the G-proteins identified by ADP-ribosylation or immunostaining in several subcellular fractions from skeletal muscle, are implicated in the modulation of calcium release from sarcoplasmic reticulum. These results suggest that a Pertussis toxin sensitive G-protein is present at the loci of E-C coupling, and that it serves to regulate the calcium release.

Adenosine Diphosphate Ribose↗
PubMed1989

[Contraction of skeletal muscles: regulation of calcium intracellular movements].

The different membrane systems and proteins involved in the control of intracellular calcium movements in the skeletal muscle cell are described. These include the sarcoplasmic reticulum, that Ca(++)-ATPase sarcoplasmic reticular calcium pump, transverse tubules, calcium channels, and the ryanodine receptor protein. The significance of these systems is shown clearly in the myopathies, where the main errors involved do not concern the contractile system, but the command and control mechanisms.

Calcium↗
PubMed1989

Progress report on the Canadian Multicentre Trial of tetrahydroaminoacridine with lecithin in Alzheimer's disease.

Since the discovery of a significant depletion of acetylcholine in discrete areas of the brain of patients affected by Alzheimer's disease, attempts at symptomatic therapy have concentrated on acetylcholine supplementation, an approach that is based upon the efficacy of dopaminergic supplementation therapy for Parkinson's disease. Choline, then lecithin, used orally, failed to improve symptoms but the hypothesis that long-term choline supplementation might stabilize the course of Alzheimer's disease remains to be tested. Nerve growth factor may also offer that possibility. Bethanechol administered intracerebroventricularly did not help when a fixed dose was used but individual titration of more selective muscarinic agonists may prove more effective. In this article we report that tetrahydroaminoacridine (THA), given together with highly concentrated lecithin, appears to bring improvement in cognition and in functional autonomy using the Mini Mental State and the Rapid Disability Rating Scale-2 respectively, without change in behavior as reflected by the Behave-AD. Double-blind cross-over studies are in progress to establish its efficacy. Improvement in study design and means of assessment of cognition, functional autonomy and behavior have been made possible by these drug trials.

Aged↗
PubMed1989

Suppression of T4 secretion in a metastatic follicular carcinoma.

Despite total thyroidectomy, a patient with metastatic follicular carcinoma of the thyroid remained biologically euthyroid three months after stopping thyroxine (T4) therapy. Thyroid hormone production was investigated by means of a modified tri-iodothyronine (T3) suppression test, in which serum T4 was used as a suppression marker. After three weeks of oral T3 (Cytomel) therapy (50 micrograms/day), the serum T4 decreased from normal (108 nmol/L) to undetectable values. However, even though suppressive therapy was effective in preventing TSH dependent hormone secretion by the tumor, it did not prevent tumor growth and the eventual death of the patient.

Adenocarcinoma↗
PubMed1988

Gallium-67 pulmonary uptake in eosinophilic pneumonia.

Eosinophilic pneumonia is usually diagnosed based on the findings on chest x-ray, white blood count, and transbronchial biopsy. After reporting a case of Ga-67 lung uptake in eosinophilic pneumonia, its histopathology is discussed and the mechanisms of Ga-67 uptake by inflammatory lesions are reviewed.

Gallium Radioisotopes↗
PubMed1988

Spinal cerebrospinal fluid leak demonstrated by radioisotopic cisternography.

Many conditions are known to cause a cerebrospinal fluid (CSF) fistula; one of them is lumbar puncture for contrast myelography. Reported here is the case of a man who underwent contrast myelography at the L2-L3 level and who presented with postural headaches and lumbalgia with radiation to the legs three weeks after the procedure. Tc-99m albumin isotopic cisternography at the L5-S1 level was performed and clearly depicted a functional CSF leak through the dura at the L2-L3 level and CSF suffusion along several rachidian roots. Scinticisternography may thus be used to localize accurately a CSF leak.

Adult↗
PubMed1988

Premenopausal bone mineral content relates to height, weight and calcium intake during early adulthood.

The influence of dietary and anthropometric factors on bone mineral content was studied in 183 healthy premenopausal French-Canadian women aged between 40 and 50 years and living in the same area. Dietary evaluation of their calcium (Ca), caffeine and alcohol intake since the age of 20 was performed in all cases. Age, height, weight, exercise level, cigarette smoking, parity and estrogen were also recorded. Bone mineral content of the L2 to L4 vertebrae (BMCL, n = 183) and forearm (BMCF, n = 137) were measured respectively by dual and single photon absorptiometry. While stepwise regression analysis showed a significant relationship between total BMCL and height, weight and Ca intake, this only occurred with weight and Ca intake when BMCL was corrected for height of L2-L4 (BMCL/cm) or for bone scan area of L2-L4 (BMCL/cm2). BMCF expressed per unit of length correlated to height only. When subjects were divided into three groups according to their Ca intake (less than 500 mg/day, between 500 and 1000 mg/day and greater than 1000 mg/day), the mean BMC adjusted for significant covariables (height and weight) was statistically different for the low and high intake groups at both sites (BMCF, F = 3.9, P = 0.02; BMCL, F = 4.2, P less than 0.02; BMCL/cm, F = 6.1, P less than 0.005; BMCL/cm2, F = 4.4, P less than 0.02). These findings indicate that, of the variables considered, Ca intake, height and weight were the only significant factors related to bone mass in our homogeneous population. It is therefore suggested that Ca intake in early adulthood influences the axial and appendicular bone mass in premenopausal women.

Adult↗
PubMed1988

Scintigraphic study of duodenal-gastric reflux in cases of primary gastropathy, chronic ulcer of the duodenal bulb, and Moynihan's disease.

There are several methods for detection of bile in the stomach, but none has proven satisfactory. It appears that the scintigraphic study with quantitation of duodenal-gastric reflux after corrections for the overlap of the stomach by the liver and bowel is more reliable, noninvasive, and physiologic. Fifty-four patients were divided into groups according to their clinical presentation; seven asymptomatic volunteers, 20 patients with duodenal-gastric reflux gastropathy (DRG), 16 patients with recurrent ulcers of the duodenal bulb (RUD), and 11 patients with Moynihan's disease. Each of the 47 dyspeptic patients underwent an endoscopic examination and a scintigraphic study with [99mTc]disofenin for detection and quantitation of duodenal-gastric reflux. Endoscopy revealed the presence of bile in the stomach of 16 out of 20 DRG and four out of 16 RUD, while ten out of 11 patients with Moynihan's disease had clear gastric juice. Most of the DRG cases (15 out of 20) and half of the RUD (eight out of 16) presented reflux greater than 1.5%, while of the 11 Moynhihan, ten presented reflux less than 1.5% and all the asymptomatic volunteer subjects less than 1%. This quantitation method allowed us to perceive clearly the low % of reflux in the "normal asymptomatic" subjects compared with the DRG-type of dyspeptic patients. Among the dyspeptic, the distinction seems more evident between the DRG type and the Moynihan type. Occasionally, the scintigraphic method permits identification of patients with slower gallbladder evacuation (eight out of 47 dyspeptic in our study), adding valuable information for the diagnostic approach to dyspeptic patients.

Adult↗
PubMed1987

Localization of abnormal parathyroid gland(s) using thallium-201/iodine-123 subtraction scintigraphy in patients with primary hyperparathyroidism.

Tl-201/I-123 subtraction scintigraphy was performed in 17 patients with clinical symptoms and biochemical measurements suggestive of primary hyperparathyroidism. Nineteen abnormal sites were identified. These results were correlated with PTH measurements and surgical findings. Three sites were considered unrelated to the parathyroid glands, two corresponding to palpable thyroid nodules and one to muscle uptake of unknown origin. One scintigram did not reveal either of two abnormal glands while two others were considered falsely positive in view of surgical failure. Fourteen sites corresponded to abnormal parathyroid gland at surgery; five glands, weighing more than 2000 mg, could be correctly located on the Tl-201 scintigraphy prior to the subtraction procedure; six glands, weighing between 500 and 2000 mg, were easily localized after the subtraction procedure; three glands, weighing between 180 and 200 mg, were correctly localized after further manipulation of the subtraction procedure. In a patient with parathyroid hyperplasia, one gland, weighing 150 mg, was not located and another was not found upon surgery. Overall sensitivity was 87.5%. A positive correlation between PTH levels, tumor weight, and ease of detection on scintigraphy was found. This correlation was particularly useful in excluding large abnormal uptake related to thyroid disorder or artifact. The results suggest that Tl-201/I-123 parathyroid scintigraphy could become an alternative to Tl-201/Tc-99m parathyroid scintigraphy, with possibly improved detection of low weight abnormal parathyroid glands.

Adenoma↗
PubMed1987

Indium-111 leukocyte scanning of the abdomen. Analysis of its value for diagnosis and management of inflammatory bowel disease.

Indium-111 leukocyte scanning of the abdomen (IAS) was performed in 10 patients with ulcerative colitis and in 39 patients with Crohn's disease involving the small intestine (in 25 occasions) and/or the colon (17 cases). Radionuclide uptake by the gut was seen in 84% of the patients with active inflammation. We compared the extent of the disease displayed by IAS with the findings obtained by either radiological or endoscopic studies or at surgery. In two-thirds of the patients, the IAS gave an accurate evaluation of the extent of the disease (sensitivity 68%). False-positive IASs were not seen in small bowel disease (specificity 100%), but were observed on 4 occasions on the colon (specificity 86%). The intensity of the radionuclide uptake could not be correlated with the clinical activity of the disease as evaluated by the Crohn's disease activity index. These results suggest that IAS is not superior to the standard procedures used to detect and localize inflammatory bowel disease and that IAS cannot replace these techniques. However, the simplicity of IAS and the complete lack of complications associated with its use render it useful in the evaluation of the extent and distribution of inflammation in some patients, mainly those with severe disease in whom standard diagnostic procedures would be contraindicated.

Abdomen↗
PubMed1987

Budd-Chiari syndrome: typical and atypical scintigraphic aspects.

Budd-Chiari syndrome, a well known entity, is often difficult to diagnose, mostly due to the nonspecificity of its symptomatology. Radiocolloid liver scans were evaluated in eight cases of this disease, proven by surgical biopsy. Five cases showed the "classic" scintigraphic pattern of caudate lobe hypertrophy (62.5%), and other abnormalities observed included segmental hepatic insufficiency, diffuse hepatic insufficiency, and relative hypertrophy of both the caudate lobe and a portion of the parenchyma of segment VI (one case each). An experimental study of hepatic venous drainage performed on livers at autopsy revealed four groups of accessory hepatic veins in addition to the main hepatic veins. The occlusion of various parts of this drainage appears to relate to the various scintigraphic patterns that were encountered in patients with Budd-Chiari syndrome. A review of the literature revealed three additional patterns previously reported in association with Budd-Chiari syndrome (normal scan, diffuse hepatomegaly, and multiple filling defects). If all these variations are appreciated, liver scanning can be a valuable screening tool for Budd-Chiari syndrome and may also serve as a noninvasive means of follow-up.

Budd-Chiari Syndrome↗
PubMed1986

Abdominal patterns of indium-111 labeled leukocyte imaging.

In-111 oxine WBC abdominal scanning is now a widely accepted technique for the detection of abdominal infectious processes. High sensitivity and specificity are achieved. In-111 labeled leukocyte accumulation, however, does not always suggest the diagnosis of abscess. Higher specificity could be obtained by the knowledge of the In-111 leukocyte distribution pattern in the abdomen in other pathologic states like inflammation of abdominal wounds, stoma; surgical complication without abscess formation; inflammatory or ischemic bowel disease; or swallowing leukocytes which subsequently are visualized in the intestinal lumen. One hundred fifty-two consecutive WBC scans performed over 18 months were reviewed and classified according to their pattern of uptake: 96 cases showed no abdominal uptake, and 56 had accumulation of leukocytes in the abdomen. Twenty-eight of these patients had proven abdominal abscess, and the remaining 26 were positive due to other causes. This report briefly discusses the distribution pattern of In-111 labeled leukocytes in the latter patients and compares the results obtained using different diagnostic criteria.

Abdomen↗