Search PubMed⌕ Search

Biomedical subjects

D F Smith

Publications and source records attributed to D F Smith.

At least 271 records · Page 15Linked to original sources
PubMed1985

Selective association in conditioned stress-induced analgesia: functional differences in interoceptive and exteroceptive sensory pathways.

Rats were used to determine whether stress-induced analgesia (SIA) can be produced by conditioning with interoceptive stimuli (LiCl) as with exteroceptive stimuli (footshock). SIA was measured using a tail-flick test. As expected, unavoidable footshock as well as conditioning with footshock produced SIA. In contrast, conditioning with LiCl failed to cause SIA. The findings support the notion of functional differences in neural substrates for conditioning by exteroceptive and interoceptive cue.

Animals↗
PubMed1985

Stereochemical considerations of the actions of some psychotropic drugs.

Stereoisomers have been used as tools to investigate the role of spatial (3-dimensional) features in neurochemical and behavioral effects of psychotropic drugs. Studies using enantiomers (optical isomers), geometrical isomers and semi-rigid molecules have shown that spatial features play a role in effects of antidepressant, antipsychotic, antiparkinsonian, and antianxiety drugs, as well as stimulants and psychotomimetics. An understanding of the role of spatial features in effects of psychotropic drugs might aid in reducing their side effects and in enhancing their therapeutic efficacy.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1985

Base excess as a prognostic and diagnostic indicator in cows with abomasal volvulus or right displacement of the abomasum.

The case records of 102 cows with abomasal volvulus and 71 cows with right-side displacement of the abomasum (RDA) were examined to determine whether the preoperative base-excess concentration of the extracellular fluid could be used both as a prognostic indicator for post-operative recovery in cattle with abomasal volvulus and as an aid in differentiating between abomasal volvulus and RDA. The survival rate of cows with abomasal volvulus decreased as the base excess concentration decreased (P = 0.08); the lowest survival rate was observed in cows with base excess less than or equal to -0.1 mEq/L. There was a significant difference (0.01 less than P less than 0.025) among base excess ranges between abomasal volvulus and RDA. All cows with preoperative base-excess concentrations less than or equal to -5.0 mEq/L had abomasal volvulus, rather than RDA.

Abomasum↗
PubMed1984

Surgical management of umbilical masses with associated umbilical cord remnant infections in calves.

Intra-abdominal umbilical cord remnant infections were diagnosed in 21 calves during a 5-year period. The urachal remnant alone was involved in 15 calves, umbilical artery remnant alone in 1 calf, and the umbilical vein remnant alone in 4 calves. Both urachus and umbilical vein were involved in 1 calf. All cases were managed surgically by ventral celiotomy. Infected urachal remnants not extending to the bladder, infected umbilical artery remnant, and infected umbilical vein remnants not extending to the liver were dissected free of surrounding adhered structures, ligated proximal to the infected segment, transected, and removed. Infected urachal remnants extending to the bladder were similarly isolated and removed after resection of the attached bladder apex. Infected umbilical vein remnants extending to the liver were marsupialized. Of 19 calves available for follow-up from 1 to 32 months after surgery, 15 recovered without any postoperative complications, 3 had short-term complications, and 1 calf developed an incisional hernia.

Animals↗
PubMed1984

Stereoselectivity of spinal neurotransmission: effects of baclofen enantiomer on tail-flick reflex in rats.

Spinal rats and rats with an intact neuraxis received an intrathecal injection of an enantiomer of baclofen. The R-enantiomer was 100-1000 times more potent than its antipode in inhibiting the tail-flick reflex, both in intact rats and in spinal rats. Spinalization enhanced the inhibitory effects of both enantiomers without altering their dose-response relations. The findings show that baclofen enantiomers have direct actions on stereo-selective spinal mechanisms and that spinalization fails to alter the stereo-selectivity of spinal mechanisms towards the enantiomers.

Animals↗
PubMed1984

A new sialyloligosaccharide from human milk: isolation and characterization using anti-oligosaccharide antibodies.

A previously undescribed sialyloligosaccharide has been isolated from human milk using a specific anti-sialyloligosaccharide antibody. Structural studies of the radiolabeled oligosaccharide by enzyme degradation and binding by specific anti-oligosaccharide sera are consistent with the following structure: (sequence in text) The oligosaccharide is present only in milk from donors who secrete A, B, or H blood group substances; this is consistent with the requirement of at least one copy of the Se (Secretor) gene necessary for the synthesis of oligosaccharides with Fuc alpha 1-2Gal . . . linkages.

Carbohydrate Conformation↗
PubMed1984

The role of spinal pathways in dopamine mediated alteration in the tail-flick reflex in rats.

The latency of the tail-flick, following intrathecal infusion of the dopamine (DA) agonist, R-apomorphine was measured in rats with intact spinal cord or with spinal cord lesions. Apomorphine failed to influence the tail-flick response in intact rats, whereas it elevated the latency of the tail-flick in rats with either total spinal cord transection, or bilateral lesions of the dorsolateral funiculi (DLF), but not in rats with lesions in either the dorsal columns or the medioventral parts of the lateral funiculi. The findings suggest that pathways in the dorsolateral funiculi modulate DA-mediated sensory processes and possible mechanisms are discussed.

Animals↗
PubMed1984

Lack of effect of tryptophan treatment in demented gerontopsychiatric patients. A double-blind, crossover-controlled study.

Twenty-eight elderly patients with dementia and in many cases also depression received daily treatment with either L-tryptophan (3g in the evening) or casein (control substance) for 1 month each, using a crossover design and double-blind procedures. Each patient's mental condition and performance ability were rated, and biological variables (serum tryptophan levels, platelet 5-HT uptake, platelet MAO activity, red blood cell thiamine, pyridoxine and riboflavin levels) were measured. Serum tryptophan levels were elevated by tryptophan treatment, but the treatment failed to have significant effects on the mental condition of the patients as a whole. Dividing the patients into two groups on the basis of the treatment during which they received their best behavioral rating failed to show significant relations to biological variables, except for differences between Vmax values for platelet 5-HT uptake. The findings indicate that long-term administration of tryptophan to gerontopsychiatric patients does not generally have beneficial effects.

Aged↗
PubMed1984

Intravenous DSA examination of patients with suspected cerebral ischemia.

We analyzed the role of intravenous digital subtraction angiography (DSA), with neck and intracranial views as a definitive pretherapy study, in patients who had symptomatic cerebral ischemia. Eighty-six patients, 25 of whom had subsequent carotid thromboendarterectomy, were examined. An adequate pretherapy intravenous DSA study allowed us to define each carotid bifurcation as either normal, having insignificant stenosis, or having significant stenosis, and the examination excluded significant tandem stenosis in the intracranial internal carotid arteries. Adequate pretherapy intravenous DSA studies were obtained in 73% of patients, including 50% of those in the presurgical group. Selective carotid arteriography was not required in these patients. Inadequate presurgical studies were predominantly due to plaque misregistration, inadequate projection, and superimposition that obscured the proximal internal carotid arteries. Selective carotid arteriography was performed in these patients prior to surgery. Inadequate studies prior to initiation of medical therapy were predominantly due to soft tissue misregistration artifact, and superimposition. Intravenous DSA is a valuable screening test and can be used to guide therapy in the majority of patients who have symptomatic cerebral ischemia.

Arterial Occlusive Diseases↗
PubMed1984

Primary biliary carcinoma: CT evaluation.

Fifty-three patients with documented primary biliary carcinoma were studied with computed tomography. Twenty-six patients had gallbladder carcinoma and 27 patients had carcinoma of the biliary ductal system. Ninety percent of patients with gallbladder cancer had an intraluminal mass. Local invasion into the liver was common. The majority of patients with biliary ductal carcinoma had dilated bile ducts, while only 50% of patients with gallbladder cancer had biliary ductal dilatation. The most common location of tumor involving the extrahepatic biliary ductal system was the distal common bile duct. This occurred in eight patients out of 27, or 30% of the cases.

Adult↗