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Biomedical subjects

J Hamilton

Publications and source records attributed to J Hamilton.

At least 55 records · Page 3Linked to original sources
PubMed1988

Protein kinase activities in the parathyroid gland: proparathyroid hormone, parathyroid hormone and secretory protein-I as substrates for phosphorylation.

We have identified two protein kinase activities in homogenates of bovine parathyroid tissue following fractionation on DEAE columns. One of these is a protein kinase C based upon its requirement for calcium and phosphatidylserine and the other one is probably M kinase. The protein kinase C phosphorylated both proparathyroid hormone and parathyroid hormone but not secretory protein-I (SP-I). Neither N [1-34] or C [35-84] terminal hormonal fragments were phosphorylated, suggesting that the structure of the intact PTH molecule is required for recognition by the enzyme. A second kinase activity behaving like M kinase was also obtained. This activity, which was not separable from a cAMP dependent kinase, was maximal with only 50 mM MgCl2 as cofactor. SP-I was readily phosphorylated by this activity but parathyroid hormone was not.

Animals↗
PubMed1987

Purification and partial amino acid sequencing of rat bone tumor (UMR106) alkaline phosphatase.

Cultured rat osteosarcoma (UMR106) alkaline phosphatase was purified to apparent homogeneity by sequential application of polyclonal antibody affinity, DEAE-cellulose, and Sepharose CL-6B chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the enzyme preparation treated with sodium dodecyl sulfate and mercaptoethanol showed the presence of a dominant band (using silver staining) corresponding to a molecular weight of 80,000. The amino acid composition was similar to those of various alkaline phosphatases. The N-terminal amino acid sequence was determined as follows: Phe-Val-Pro-Glu-Lys-Glu-Lys- Asp-Pro-Ser-Tyr-Trp-Arg-Gln-Gln-Ala-Gln-Glu-Thr-Leu- Lys-Asn-Ala-Leu-Lys-?-Gln-Lys-?-Asn-Val-Asn-Ala-Lys.

Alkaline Phosphatase↗
PubMed1987

Localization of the Goodpasture epitope to a novel chain of basement membrane collagen.

The chain origins of subunits M1, M2*, and M3 previously described (Butkowski, R. L., Wieslander, J., Wisdom, B.J., Barr, J.F., Noelken, M.E., and Hudson, B.G. (1985) J. Biol. Chem. 260, 3739-3747) of the globular domain of basement membrane collagen were identified, by amino-terminal amino acid sequence analysis, with respect to their relationship to the chains of collagen IV. M1 comprises two polypeptides which correspond to the noncollagenous segments (NC1) of the alpha 1 ad alpha 2 chains of collagen IV. M2*, containing the Goodpasture epitope, and M3 are distinct from these two constituents and from each other but have Gly-X-Y triplets and hydroxyproline at their amino terminus, reflecting the fact that each has a collagen chain origin. These results indicate the presence of two new collagen chains in basement membrane. These new chains appear to be integral components of collagen IV molecules. Alternatively, they could represent new molecular species of basement membrane collagen containing a globular domain, comprising M2* and M3, with physicochemical properties very similar to those of collagen IV.

Amino Acid Sequence↗
PubMed1987

Purification and partial amino acid sequencing of bovine kidney alkaline phosphatase.

Bovine kidney alkaline phosphatase (ALPase) was purified by the sequential application of monoclonal anti-bovine cartilage ALPase affinity, DEAE-cellulose, and Sepharose CL-6B chromatography. Sodium dodecyl sulfate-polyacrylamide-gel electrophoresis showed the presence of a single band corresponding to a molecular weight of 80,000. The N-terminal amino acid sequence of bovine kidney alkaline phosphatase was determined as follows: Leu-Val-Pro-Glu-Lys-Asp-Pro-?-Tyr-Trp-Arg-Asp-Gln-Ala-Gln.

Alkaline Phosphatase↗
PubMed1987

Eye-tracking, attention and amphetamine challenge.

Smooth pursuit eye movement (SPEM) performance has been linked to nonvoluntary attentional processes. Amphetamine is a psychotropic drug with documented effects on attentional performance. In order to evaluate the relationship between SPEM performance and amphetamine's attentional effects, SPEM performance was measured prior to and following amphetamine administration in five bipolar patients and eight obsessive-compulsive patients. In these 13 patients, amphetamine did not significantly alter the accuracy of SPEM in the two patient groups. However, significant negative correlations were observed in the obsessive-compulsive patients and in the combined patient groups between baseline SPEM impairment and changes in eye-tracking accuracy following amphetamine, i.e. individuals with poorer SPEM accuracy improved while better SPEM performers deteriorated in tracking accuracy during amphetamine treatment.

Attention↗
PubMed1987

Treatment of claudication with pentoxifylline: are benefits related to improvement in viscosity?

Forty-five patients with short-distance claudication were treated with pentoxifylline. The initial claudication distance increased significantly (32.5 m, p = 0.02) and the absolute claudication distance (ACD) increased significantly (49.5 m, p = 0.001) while the patients were receiving pentoxifylline. Patients with initial elevated viscosity levels were more likely to have decreased viscosity with pentoxifylline than were patients with normal viscosity levels (p = 0.01). No significant improvement in ACD or viscosity was noted in 51% of patients. Both ACD and viscosity improved in 15% of patients, viscosity improved without improvement in ACD in 9%, and ACD improved without improvement in viscosity in 25%.

Blood Viscosity↗
PubMed1987

Experiential sampling in the study of multiple personality disorder.

The authors describe the application of experiential sampling, a new time-sampling method, to the assessment of rapid state changes in a woman with multiple personality disorder. She was signaled at random intervals during study periods and asked to provide information on alternate personality switches, amnesia, and mood state. The alternates displayed some characteristics that were as different as those occurring between separate individuals studied previously with this method. There were notable discrepancies between the self-report study data and information reported during therapy hours. The authors conclude that the phenomenology of multiple personality disorder is frequently more complex than is suspected early in the course of treatment.

Adult↗
PubMed1986

A prospective study of inhibitive casting as an adjunct to physiotherapy for cerebral-palsied children.

The effect of a three-week course of inhibitive casting and neurodevelopmental therapy on the static muscle tonus, developmental skills, passive range of ankle dorsiflexion and gait pattern was determined in 32 cerebral-palsied children. Two weeks after treatment, passive range of ankle dorsiflexion and foot-floor contact in walking had improved significantly but there was no significant change in the static muscle tone or developmental skills. After five months the improvements in ankle dorsiflexion and walking pattern were no longer evident. Further objective studies to determine the effect of 'inhibitive casting' are necessary before the modality is used indiscriminately.

Ankle↗
PubMed1986

Platelet interaction with a pancreatic ascites tumor.

The mechanism leading to the hypercoagulability in pancreatic carcinoma is unclear. The rapid progress of the disease after its diagnosis and the inaccessibility of the tumor make studies on the mechanism difficult in man. With the successful induction of this malignancy and conversion of it into an ascites tumor in Syrian golden hamsters, interactions between isolated tumor cells and individual hemostatic components can be investigated. In this paper, studies on in vitro tumor cell-platelet interactions and some hemostatic changes in hamsters following intravenous injection of isolated tumor cells are described. Freshly isolated tumor cells and tumor-cell sonicates, but not those that had been kept at 4 or -70 C overnight, induced comparable aggregation of human platelets in both heparinized and citrated platelet-rich plasmas (hPRP and cPRP). The aggregation was not followed by clot formation; a specific synthetic thrombin inhibitor had no effect on the aggregation in either hPRP or cPRP. Washed and gel-filtered platelets, even in the presence of 5% of citrated or heparinized platelet-poor plasma (cPPP or hPPP) failed to be aggregated by tumor cells. Tumor-cell-induced platelet aggregation was accompanied by thromboxane formation and serotonin release, both of which were several orders of magnitude greater in cPPP than in hPRP. Aspirin, apyrase, and PGI2 all inhibited tumor-cell-induced platelet aggregation in both PRPs, but the inhibition by aspirin was minimal. Intravenous infusion of isolated tumor cells into normal hamsters resulted in a 50% reduction of platelet count and a 20-30% decline in antithrombin III and fibrinogen. Platelet aggregates and fibrin strands were seen in the lungs of these animals.

Animals↗
PubMed1985

Auditory hallucinations in nonverbal quadriplegics.

When a system for communicating with nonverbal, quadriplegic, institutionalized residents was developed, it was discovered that many were experiencing auditory hallucinations. Nine cases are presented in this study. The "voices" described have many similar characteristics, the primary one being that they give authoritarian commands that tell the residents how to behave and to which the residents feel compelled to respond. Both the relationship of this phenomenon to the theoretical work of Julian Jaynes and its effect on the lives of the residents are discussed.

Adult↗
PubMed1985

Multicenter seroepidemiologic study of the impact of cytomegalovirus infection on renal transplantation.

The effects of cytomegalovirus (CMV) infection on patient and allograft survival were determined in 1245 renal transplant recipients from 46 transplant centers. When an antilymphocyte preparation was administered to cadaveric allograft recipients, those at risk for primary CMV had a worse outcome than similar patients treated with prednisone and azathioprine (53.1% alive at 6 months with a functioning allograft vs. 70.8%, P = .05) or patients at risk for reactivation CMV (53.1% vs. 71.1%, P = .035). Patients at risk for reactivation CMV had a better outcome if they received an antilymphocyte preparation (71.1% vs. 60.8%, P less than .01). The type of immunosuppression had no effect on patients without CMV. Living-related donor transplantation was not significantly influenced by CMV or type of immunosuppression. We conclude that CMV infection is strongly influenced by the form of immunosuppression employed, and that both are important determinants of the outcome of cadaveric renal transplantation.

Age Factors↗
PubMed1985

Carnitine and carnitine transferases in the intestinal mucosa of suckling rats.

Carnitine acetyltransferase and palmitoyltransferase activity in the mucosa of the small intestine of rats rises after birth and falls at the time of weaning. The carnitine contents of the mucosa (free, acetyl-, palmitoyl- and total) decrease postnatally, reaching adult levels at the time of weaning. Orally administered 14C-carnitine is only slowly absorbed so that radioactivity is still high in plasma and organs 6 h later, whereas label given subcutaneously disappears from the plasma and tissues more rapidly. The intestinal mucosa also takes up carnitine from 14C-carnitine administered subcutaneously. It is concluded that carnitine plays an important role in the gut of suckling rats.

Acetyltransferases↗
PubMed1984

Alpha-adrenergic-induced changes in hamster (Mesocricetus) brown adipocyte respiration and membrane potential.

Respiratory rates of brown adipocytes were stimulated by 10 microM phenylephrine, the magnitude of this stimulation being about only one-third that evoked by 1 microM isoproterenol, or norepinephrine. The smaller thermogenic response to phenylephrine did not reflect limited substrate availability as shown by the finding that respiration with phenylephrine plus butyrate was not greater than that with phenylephrine or butyrate alone. These data also imply that the thermogenic response to the alpha-agonist does not involve a significant degree of mitochondrial uncoupling. Examination of in vivo changes in brown adipocyte membrane potentials indicated that phenylephrine and isoproterenol can each elicit multiphasic responses (i.e. depolarization followed by hyperpolarization and a second depolarization), although the magnitude and duration of each phase differed for the two agonists. The initial depolarization occurring within seconds after norepinephrine injection appears to result primarily from activation of alpha-adrenergic receptors, with a small contribution from the beta-pathway. Similarly, the subsequent hyperpolarization and second depolarization primarily reflect events associated with the activated beta-adrenergic pathway, with a modest contribution from alpha-mediated events.

Adipose Tissue, Brown↗
PubMed1984

Withdrawal phenomena in subjects with essential hypertension on clonidine or tiamenidine.

The incidence and pathogenesis of withdrawal phenomena with the centrally acting drugs clonidine (CLON) and tiamenidine (TIAM) were evaluated. Thirty subjects with hypertension on hydrochlorothiazide (HCTZ) were randomized to TIAM or CLON. Blood pressure and integrated plasma catecholamine levels fell equally in response to both drugs. On withdrawal, blood pressure and pulse rose in both groups with no difference between them. Three subjects had symptoms of withdrawal, four had blood pressure overshoot above pretreatment levels of 10 mm Hg or more, and eight had a rise in blood pressure of 30 mm Hg systolic or 20 mm Hg diastolic. There was no difference between TIAM and CLON in these effects. There was a direct correlation between blood pressure rise and increase in integrated plasma norepinephrine levels. We conclude that the incidence of withdrawal phenomena in subjects on TIAM or CLON is infrequent and that there is a direct relationship between the rise in blood pressure and the loss of suppression of catecholamines by these drugs.

Adult↗
PubMed1984

Analysis of emotional status during the hospital treatment of a borderline patient.

This single case study illustrates a methodology for identifying recurrent pathological emotional states in a hospitalized, borderline patient. Parallel therapeutic inputs are delineated and examined in terms of patient-specific responses. The results indicate that ratings of nursing notes recorded across three periods of hospitalization can reliably isolate the patient's most salient and debilitating emotional states. State-specific therapeutic interventions are extracted and their effectiveness noted. The analyses illustrate clinical phenomena which are congruent with what is known about borderline symptomatology. In addition, the study locates therapeutic errors which often occur when working with difficult patients.

Adult↗