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Biomedical subjects

B Gordon

Publications and source records attributed to B Gordon.

213 records · Page 12Linked to original sources
PubMed1966

Characterization of trisubstituted cholanoic acids in human feces.

The trisubstituted cholanoic acids in human feces have been studied by gas chromatography-mass spectrometry. The following bile acids have been identified: 3 Beta,7alpha,12alpha-trihydroxy-, 3 Beta,7 Beta,12alpha-trihydroxy-, 3alpha,7alpha-dihydroxy-12-keto-5 Beta-cholanoic acids and 3alpha,7alpha,12alpha-trihydroxy-5alpha-cholanoic acid. The presence in human feces of 3alpha,7alpha,12alpha-trihydroxy-, 3alpha,7,12alpha-trihydroxy-, and 3alpha,12alpha-dihydroxy-7-keto-5 Beta-cholanoic acids has been confirmed. The composition of bile acids in human feces is summarized and possible metabolic interrelationships suggested.

Bile Acids and Salts↗
PubMed1966

Identification of mono- and dihydroxy bile acids in human feces by gas-liquid chromatography and mass spectrometry.

The mono- and disubstituted cholanoic acids present in human feces have been investigated. Extracts of feces were fractionated on silicic acid column and individual bile acids were isolated by preparative thin-layer chromatography. The isolated compounds were studied by gas-liquid chromatography of the methyl esters, partial trimethylsilyl ethers, oxidation products, and trifluoroacetates. The probable structures deduced were confirmed by gas chromatography-mass spectrometry and by comparisons with authentic compounds. The following derivatives of 5 Beta-cholanoic acid not previously isolated from human feces were identified: 3,12-diketo, 3-keto-12alpha-hydroxy, 3alpha,12 Beta-dihydroxy, 3 Beta,12 Beta-dihydroxy, 3-keto-7alpha-hydroxy, 3alpha-hydroxy-7-keto, 3 Beta,7alpha-dihydroxy, 3alpha,7alpha-dihydroxy, and 3alpha,7 Beta-dihydroxy. The presence of 3-keto-, 3 Beta-hydroxy-, 3alpha-hydroxy-, 3 Beta-hydroxy-12-keto-, 3alpha-hydroxy-12-keto-, 3 Beta,12alpha-dihydroxy-, and 3alpha,12alpha-dihydroxy-5 Beta-cholanoic acids was confirmed. Evidence was obtained for the presence of two bile acids having at least one hydroxyl group at a carbon atom other than C(3), C(7), or C(12).

Bile Acids and Salts↗
PubMedDate not supplied

Unilateral renal cystic disease in an adult.

Unilateral renal cystic disease (URCD) is a rare, nonfamilial, nonprogressive, unilateral cystic disorder of the kidney. Very few adults with this condition have been documented [1-4]. We describe a case with a 30 year radiologic follow-up. Absence of a family history of cystic renal disease, benign clinical course through adulthood, and limitation of the process to one kidney distinguish this condition from asymmetric autosomal dominant polycystic kidney disease (ADPKD).

Diagnosis, Differential↗
PubMedDate not supplied

Embolotherapy for small bowel hemorrhage from metastatic renal cell carcinoma: case report.

Embolization for control of hemorrhage in the small bowel carries a significant risk of bowel infarction. A case is presented where severe gastrointestinal hemorrhage from a hypervascular renal cell carcinoma metastasis to the jejunum was effectively controlled by superselective embolization of mesenteric tumor supply arteries with Gelfoam particles. Adjacent normal mesenteric arteries remained open. It is concluded that in specific instances where direct mesenteric feeders to a tumor can be catheterized, such embolization can be performed safely.

Aged↗
PubMedDate not supplied

Transneuronal WGA-HRP: can it demonstrate development of ocular dominance patches and effects of monocular deprivation?

We have attempted to use intraocular injections of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) to label ocular dominance patches in developing layer 4 of cat visual cortex. The cortices of animals killed at 49 days or later showed normal ocular dominance patches similar to those seen in [3H]proline material. Animals killed at 42 days showed some patches, but also showed unsegregated regions. Animals killed younger were difficult to stain and did not have patches. We also examined the ability of the WGA-HRP technique to demonstrate the effects of monocular deprivation (MD). MD for the first 3 months of life produced expansion of the afferents from the nondeprived eye and retraction of the patches from the deprived eye. One week of MD at about 5 weeks of age produced an expansion of the patches innervated by the nondeprived eye, but did not obviously affect the patches innervated by the deprived eye. We conclude that WGA-HRP is useful for examining the effects of long-term MD on ocular dominance patches but not for following the development of segregation. Its advantages over the [3H]proline technique are that it does not require a delay of many weeks before the sections can be examined and is much less expensive.

Animals↗
PubMedDate not supplied

The development of MK-801, kainate, AMPA, and muscimol binding sites in cat visual cortex.

Previous work using homogenate binding has shown that the development of (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10imin e maleate (MK-801) binding in cat visual cortex increases from 21 days to 42 days, the height of the plastic period, and decreases in adulthood. We have studied the generality of this finding by examining the development of NMDA binding sites in several brain regions and by examining the development of other binding sites in the visual cortex. After confirming the original finding, we extended it by showing that the sensitivity of MK-801 binding sites to glutamate and glycine decreases when the cat becomes an adult. We then examined the regional specificity of MK-801 binding. Retinal binding did not change significantly with age. Binding in both visual cortex and hippocampus increased significantly from 7 days to 42 days regardless of whether binding was measured per milligram wet weight or per milligram protein. The decline from 42 days to adulthood was less dramatic in the hippocampus than in the visual cortex and was statistically significant only when binding was measured per milligram protein. Saturation analyses also showed a difference in the two structures. Bmax in the visual cortex, but not in the hippocampus, decreased from 42 days to adulthood. To determine whether these developmental changes were specific to MK-801 binding sites, we compared the age-dependent binding of MK-801, kainate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and muscimol. Like MK-801, kainate binding increased from 7 days to 42 days and decreased from 42 days to adulthood. AMPA and muscimol binding showed a similar increase in binding from 7 days to 42 days but did not decrease significantly from 42 days to adulthood. Displacement experiments suggest that AMPA and kainate bind to separate sites. The 42-day peak in NMDA and kainate binding suggests that their associated receptors may have a role in determining the plastic period of visual cortex.

Aging↗
PubMedDate not supplied

Combined plasma exchange and intravenous gammaglobulin in the treatment of patients with refractory immune thrombocytopenic purpura.

Plasma exchange (PE) and intravenous gammaglobulin (IVGG) are potentially effective therapies in immune thrombocytopenic purpura (ITP). In this study, eight patients refractory to IVGG and to prednisone were treated with a protocol of combined PE and IVGG therapy using a single PE on each of 3 consecutive days, followed by 2 consecutive days of IVGG at 1 g per kg. Four of the eight patients responded to the combined therapy with a mean peak platelet count of 132,000 per microliter (range, 74,000 to 225,000/microliter). Responses lasted approximately 2 weeks. These four patients were among the five who had initially responded to IVGG before becoming refractory; none of the three patients without an initial response to IVGG responded to the combined therapy. Age, duration of disease, and splenectomy status did not appear to be related to response to the combined therapy. Two patients began maintenance treatment (1 PE followed by 1 g/kg IVGG on the same day), but both became unresponsive after three treatments. PE combined with IVGG may be a useful treatment for some patients with refractory ITP who have uncontrollable bleeding or require major surgery. The development of resistance to IVGG effect may be mediated by an increase in the level of antiplatelet antibodies. PE, by lowering antiplatelet antibody levels, may then allow IVGG infusion to be effective again in elevating the platelet count.

Adolescent↗
PubMedDate not supplied

Placebo-controlled pilot study of centromedian thalamic stimulation in treatment of intractable seizures.

Stimulation of centromedian (CM) thalamic nuclei has been proposed as a treatment for seizures. We implanted programmable subcutaneous (s.c.) stimulators into CM bilaterally in 7 patients with intractable epilepsy to test feasibility and safety. Stimulation was on or off in 3-month blocks, with a 3-month washout period in a double-blind, cross-over protocol. Stimuli were delivered as 90-microseconds pulses at 65 pulses/s, 1 min of each 5 min for 2 h/day, with voltage set to half the sensory threshold. Stimulation was safe and well-tolerated, with a mean reduction of tonic-clonic seizure frequency of 30% with respect to baseline when stimulator was on versus a decrease of 8% when the stimulator was off. There was no improvement in total number of generalized seizures with stimulation, and treatment differences were not statistically significant. Stimulation at low intensity did not alter the EEG acutely, but high-intensity stimulation induced slow waves or 2-3 Hz spike-waves with ipsilateral frontal maximum. In an open-label follow-up segment with stimulator trains continuing for 24 h/day, 3 of 6 patients reported at least a 50% decrease in seizure frequency. There were no side effects. This pilot project demonstrated the feasibility of controlled study of thalamic stimulation in epilepsy, but further study will be needed to demonstrate efficacy.

Adolescent↗
PubMedDate not supplied

Clinical and electroencephalographic evidence for sites of origin of seizures with diffuse electrodecremental pattern.

A diffuse electrodecremental ictal pattern (DEP) has been associated with tonic seizures and, less often, with other forms of epilepsy and has been considered to reflect a generalized seizure disorder of diffuse cortical or subcortical (brainstem) origin. In some seizures associated with DEP, however, focal ictal manifestations have been observed. We reviewed the records of all patients admitted to our seizure monitoring unit for 3 years and detected 39 patients with seizures associated with DEP. In 23 of 39 patients, clinical ictal behaviors resembled seizures of unilateral supero/mesiofrontal lobe origin and interictal EEG showed a prominent unilateral frontal component. Nine of 39 had complex absences (CA)/complex partial seizures (CPS); 4 of them were of unilateral frontal lobe origin. Seven of 39 patients had tonic or atonic seizures. Seven patients were studied further with subdural electrodes. Ictal onsets showed a high-frequency frontal lobe discharge. We conclude that in a subgroup of patients a generalized electrodecremental pattern on scalp EEG results from a regional cortical high-frequency ictal discharge originating in a single frontal lobe.

Adult↗
PubMedDate not supplied

[Immunohistologic study of the epiretinal membranes in proliferative diabetic retinopathy and retinal detachment with vitreo-retinal proliferation].

An immunohistological study was performed in specimens of epiretinal membranes obtained during surgery in patients with proliferative diabetic retinopathy or retinal detachment with proliferative vitreoretinopathy. Using immunostaining procedures, these membranes were found to contain great amounts of immunoglobulins and complement, as well as a strong expression of class II antigens. These results confirm the involvement of auto-immune phenomena in intra-ocular proliferative diseases and the close relationship between the immune system and peptide growth factors.

Cell Division↗