An aging effect in striatal fluorodopa uptake? Large versus small ROIs.
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Aging↗
Biomedical subjects
W R Martin
Publications and source records attributed to W R Martin.
Assessment of fetal tissue transplantation in Parkinson's disease: does PET play a role?
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Animals↗
Phantom angina.
A 49-year-old man with a history of traumatic left above-elbow amputation was hospitalized for surgical management of a phantom pain syndrome. Evaluation revealed a history of exertional chest pain radiating into the phantom limb. Exercise testing reproduced the pain symptoms and demonstrated electrocardiographic ischemic S-T segment depression. Coronary angiography revealed severe three-vessel coronary artery disease. The patient underwent coronary artery bypass graft surgery which eliminated the anginal component of his phantom pain syndrome and abolished evidence of exercise-induced myocardial ischemia. This case illustrates that myocardial ischemia can produce phantom pain with the characteristics of typical angina and indicates the need for thorough evaluation of patients presenting with unusual features of phantom pain.
Angina Pectoris↗
Cross-sectional geometrical properties and bone mineral contents of the human radius and ulna.
The mechanical strength of the human radius and ulna depends on their geometrical and material properties. This study quantifies the cortical bone cross-sectional properties of the adult radius and ulna (cross-sectional area, thickness, centroids, area moments of inertia and section moduli) using computerized tomographic (CT) scanning coupled with image processing along the lengths of eight human cadaveric forearms. Bone mineral mass and apparent ash density were also quantified at serial locations. Sites of significant variation of selected geometric and mineral properties along the length of each forearm bone were determined. Our results show that interpolation of CT measurements made at 10 and 30% of the radial length in the radius and 30 and 90% of the radial length in the ulna can provide approximate geometric values over the 10-90% region. This information can be used to develop a protocol using the fewest sites to clinically assess changes in forearm bone geometry. Regression analyses did not show significant linear relationships between geometric properties and apparent cortical ash density. Thus, CT derived geometric properties are not helpful in estimating the extent of changes in bone density. Area moment of inertia results suggest that the junction of the middle and distal third of the radius, and the ulnar shaft region may have increased vulnerability to fractures. The former is likely due to the change in moment of inertia values, whereas the latter is due to the relatively small magnitude of cross-sectional moments along the ulnar shaft as compared to the proximal or distal ends. This is consistent with fracture patterns observed clinically when a single forearm bone is fractured: Galeazzi fracture of the radius and nightstick fracture of the ulna.
Biomechanical Phenomena↗
Pharmacokinetics of nordiazepam in physical dependence and precipitated abstinence in dogs.
Previous studies suggested that the extensive accumulation of benzodiazepines is an important factor in the induction of physical dependence. The mechanistic basis for accumulation of nordiazepam (ND) and its metabolite, oxazepam (OX), have been examined in crossover studies in drug-naive and in ND-dependent dogs that exhibited a flumazenil-precipitated abstinence syndrome. ND and parent OX have similar pharmacokinetic profiles. Steady-state plasma levels of ND and OX cannot be predicted from single-dose pharmacokinetics. Reduced plasma clearance of ND and altered plasma protein binding were observed in dogs physically dependent upon ND. The benzodiazepine antagonist, flumazenil, significantly reduces steady-state plasma levels of total and free ND.
Administration, Oral↗
Precipitated abstinence in the diazepam-dependent rat.
Physical dependence was produced in the rat by exposure to continuous release of diazepam from silastic capsule implants (recrystallized diazepam) or by dosing through a gastric fistula. The precipitated abstinence syndrome induced by the IV infusion of flumazenil was characterized by clonic and tonic-clonic seizures, retropulsion, digging, rearing, head, limb and body tremors, twitches and jerks of the body, and ear twitches. This abstinence syndrome differed both qualitatively and quantitatively from the milder syndrome induced in previous experiments by the intragastric administration of flumazenil in the diazepam-dependent gastric fistula rat. Capsule-implanted rats had free plasma and extraneuronal brain levels of diazepam, oxazepam, and nordiazepam in the 10(-3) and 10(-4) mg/ml range, and their brain: plasma ratios were not significantly different from 1. The diazepam capsules had a sustained release of over 28 days. These studies show that the capsule implantation technique is an efficacious way of maintaining plasma levels of diazepam and its metabolites, and producing a high level of physical dependence in the rat.
Animals↗
Elevated levels of serum mucin-associated antigen in adult patients with cystic fibrosis.
Previous studies using the CA 19-9 antibody have demonstrated that serum mucin levels in patients with cystic fibrosis (CF) are elevated and that the degree of elevation relates to the age of the patient and possibly to his or her clinical status. However, CA 19-9 only recognizes the mucin-associated blood group sialyl Le(a+) antigen, so mucin levels cannot be measured in patients without Lewis antigens. The present study used the 17B1 monoclonal antibody to measure serum mucin levels in normal subjects, and in patients with CF, patients with chronic obstructive pulmonary disease (COPD), and patients with lung transplants. Serum mucin levels were 25 ng/ml (+/- 1 SEM, n = 8) in normal subjects, 13,853 ng/ml (+/- 1,281, n = 25) in patients with CF, and 25.5 ng/ml (+/- 1.9, n = 17) in patients with COPD. Patients with CF who were sialyl Le(a-b-) also had elevated serum mucin levels (715 +/- 152, n = 2). Serum mucin levels of six lung transplant recipients with CF were elevated compared with those in normal subjects (4,621 +/- 765 ng/ml), but they were not different from serum mucin levels in six lung transplant recipients without CF (5,307 +/- 1.677 ng/ml). Preliminary characterization of the serum mucin antigen showed that: (1) in CF sera, the antigen is polydisperse and smaller than the antigen in normal sera; (2) the mucin antigen is distinct from ABO blood group antigens. Serum mucin levels may be a useful marker to follow a specific patient's response to therapy.
ABO Blood-Group System↗
Unusual arthroscopic knee lesions: case report of an intra-articular lipoma.
Intra-articular lipoma is a rare benign tumor that should be considered in the differential diagnosis of a smooth lobular synovial mass. This article reports a patient who presented with right knee pain, locking, and swelling. At surgery, an intra-articular lipoma was found.
Arthroscopy↗
Career ladder for pharmacy interns.
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Career Mobility↗
Pharmacologic characteristics of a medullary hyperalgesic center.
The effects of ethylketazocine, U-50,488, morphine and (-)-nicotine administered both i.p. and into the mid-fourth ventricle of intact rats were investigated using a conventional high intensity tail-flick reflex and one evoked with a lower intensity thermal stimulus. The sensitivity of the low intensity thermally evoked tail avoidance reflex was several times that of a high intensity tail-flick reflex in detecting the analgesic activity of morphine and yielded valid assays and relative potencies between morphine (1), EKC (18.76) and U-50,488 (0.23) when the drugs were administered ip. When the opioid drugs were administered into the fourth ventricle they produced a dose-related shortening of the latency of the low intensity thermally evoked tail avoidance reflex. (-)-Nicotine, when administered into the mid-fourth ventricle, produced analgesia in low doses and hyperalgesia in high doses. Naltrexone and mecamylamine, when administered into the fourth ventricle, produced a dose-related analgesia. Doses of naltrexone and mecamylamine which antagonize maximally hyperalgesic doses of (-)-nicotine and ethylketazocine did not produce analgesia; however, larger doses produced analgesia. These observations suggest that analgesic doses do not involve prototypic kappa opioidergic or nicotinic mechanisms. These data confirm the existence of a medullary hyperalgesic center which may have both mu and kappa opioidergic as well as nicotinic mechanisms. Furthermore, these data indicate that this medullary hyperalgesic mechanism may have spontaneous or evoked tone and provide an explanation for the analgesic action of naltrexone and mecamylamine.
3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
Complications of proximal femoral allografts in revision total hip arthroplasty.
Four revision hip arthroplasties using a well-described surgical construct involving a large frozen femoral allograft to replace a deficient proximal femur developed six major complications related to the use of the allograft or of the surgical construct. These cases represent three consecutive cases using this surgical construct performed by the senior author and one postoperative referral that used the same construct. The complications included three allograft fractures, two nonunions at the host-allograft junction, and one postoperative infection. All four of the patients previously had cemented revisions before the allograft procedure, and all had deficient proximal femurs at the time of the allograft procedure. All three of the fractures occurred at the tip of the femoral prosthesis within the allograft. The unacceptably high fracture rate, three of four, was associated with the allograft functioning as an unsupported load-bearing element in this study.
Bone Transplantation↗
Effect of the chronic dose of diazepam on the intensity and characteristics of the precipitated abstinence syndrome in the dog.
The ability of different chronic doses of diazepam to produce dependence was studied in groups of six dogs who received diazepam p.o. (0.05625, 0.225, 0.5625, 4.5, 9 or 36 mg/kg/day) every 8 hr. After 5 to 6 weeks of stabilization, the intensity of precipitated abstinence was measured by benzodiazepine-precipitated abstinence scores (BPAS) after the p.o. administration of graded doses of the benzodiazepine antagonist, flumazenil (0.66, 2, 6, 18, 36 and 72 mg/kg or a placebo). A modified Latin square design was used. Dogs receiving the two lowest stabilization doses of diazepam showed only liminal signs of precipitated abstinence even with 72 mg/kg of flumazenil. The intensity of the precipitated abstinence syndrome increased with the stabilization dose of diazepam. There was also a dose-related increase in BPAS for increasing doses of flumazenil for all doses of diazepam except the 9-mg/kg/day dose. Not only were quantitative differences observed in precipitated abstinence signs for different levels of diazepam dependence, but the pattern of abstinence signs differed also. Dogs dependent on high doses of diazepam were more sensitive to flumazenil than those dependent on lower doses. Furthermore, seizure activity was seen only in dogs dependent on 9 and 36 mg/kg/day of diazepam. BPAS increased linearly with plasma and brain total and free levels of the sum of diazepam and its metabolites (oxazepam and nordiazepam), but not with free plasma and brain levels of diazepam.
Animals↗
Drug information discrepancy.
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Advertising↗
Cerebral glucose metabolism in Parkinson's disease with and without dementia.
Although cognitive impairment is commonly associated with Parkinson's disease, the relative importance of cortical and subcortical pathologic changes to the development of dementia is controversial. Characteristic abnormalities in cortical glucose metabolism have been reported previously in Alzheimer's disease, a disease in which cortical changes predominate. We measured cerebral glucose metabolism with positron emission tomography in 20 control subjects and in 14 patients with PD with mental status ranging from normal to severely demented to determine whether changes in cortical glucose metabolism occur in early PD and whether the degree and pattern of metabolic change relate to the severity of dementia. The patients were divided into demented and nondemented groups according to the results of neuropsychological assessment. Age-adjusted covariance analyses were performed, since the age distribution varied between groups. The nondemented patients with PD showed widespread cortical glucose hypometabolism without any selective temporoparietal defects. The pattern of glucose hypometabolism seen in the demented patients with PD resembled that described in patients with Alzheimer's disease; ie, there was a global decrease in glucose metabolism, with more severe abnormalities observed in the temporoparietal regions.
Aged↗
Analgesic actions of local anesthetics and cobalt chloride in the rat brain stem.
A low-intensity thermally evoked tail avoidance reflex (LITETAR) was used to study changes in nociceptive response produced by local anesthetics and cobalt chloride microinjected into the dorsal posterior mesencephalic tegmentum (DPMT) of conscious rats. Dose-related prolongation of the LITETAR (e.g., analgesia) was observed when lidocaine, cocaine, and bupivacaine were administered into the DPMT. Analgesic actions were also demonstrated when cobalt chloride was microinjected into the DPMT. The analgesic actions of these different neuronal suppressants provide support for the hypothesis that there exists tonic activity of hyperalgesic processes in the rat brain stem.
Analgesics↗
Analgesic actions of dynorphin A(1-13) antiserum in the rat brain stem.
This study was performed to evaluate the effects of dynorphin A(1-3) antiserum when microinjected into an active hyperalgesic region within the rat brain stem. When administered within the dorsal posterior mesencephalic tegmentum (DPMT) of intact conscious rats, dynorphin A(1-13) antiserum produced rapid onset and persistent prolongation of a low intensity thermally evoked tail avoidance response (LITETAR). These analgesic actions of the dynorphin A(1-13) antiserum appeared to be dose dependent. These studies support previous hypotheses about the existence of tonically active brain stem opioid hyperalgesic process. Further, the results provide indirect evidence for a potential role of brain stem dynorphin(s) in facilitating pain.
Analgesics↗
Susceptibility of cockroaches (Dictyoptera: Blattellidae, Blattidae) to infection by Steinernema carpocapsae.
The susceptibility of American cockroaches, Periplaneta americana (L.); smoky brown cockroaches, P. fuliginosa (Serville); oriental cockroaches, Blatta orientalis L.; German cockroaches, Blattella germanica (L.); and brownbanded cockroaches, Supella longipalpa (F.), to Steinernema carpocapsae Weiser (All strain) was evaluated under laboratory conditions. A 1-ml water suspension containing 500,000 nematodes was placed on filter paper in a petri dish or the pad of a bait station. German, brown-banded, oriental, and smoky-brown cockroaches died within 1 d after placement in the petri dishes. The relative order for the LT50s were American greater than oriental greater than smoky-brown greater than brown-banded = German. All cockroaches actively groomed nematodes from legs and antennae of forced (petri dish) exposure. The LT50s for S. carpocapsae for nonforced (bait station) exposure were significantly greater than those for forced exposure. The LT50s were 3.25, 4.13, 9.86, and 11.38 d for brown-banded, German, oriental, and smoky-brown cockroaches, respectively. The relative order of the LT50s after forced (American greater than oriental greater than smoky-brown greater than German = brown-banded) and nonforced (American greater than smoky-brown greater than oriental greater than German greater than brown-banded) exposure to S. carpocapsae was inversely related to the moisture of their preferred habitats.
Animals↗
Cortical glucose metabolism in Huntington's disease.
We measured cortical glucose metabolism with positron emission tomography in 39 patients with Huntington's disease (HD) and in 34 controls. In the 23 patients with symptoms for less than 5 years, there was a 15% decrease in metabolism in frontal and inferior parietal cortex. In 16 patients with symptoms for more than 5 years, all cortical areas (except temporal) were significantly involved, with metabolic rates 25 to 30% below those of controls. These data indicate the presence of a diffuse abnormality of cortical function with early involvement of frontal lobes in HD, suggesting that the clinical manifestations may not be related solely to basal ganglia pathology, even in early disease.
Adult↗