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Biomedical subjects

M M Young

Publications and source records attributed to M M Young.

At least 37 records · Page 2Linked to original sources
PubMed1993

Insulin resistance, glucose intolerance, and hyperinsulinemia in patients with microvascular angina.

Plasma glucose and insulin responses to oral glucose and insulin-mediated glucose disposal were determined in 20 patients with microvascular angina and 20 normal volunteers who were similar in terms of age, gender distribution, and degree of obesity. Plasma glucose and insulin responses to a 75-g oral glucose challenge were significantly higher in those with microvascular angina (P < .001), as were steady-state plasma glucose concentrations after a 180-minute infusion of somatostatin, glucose, and insulin (12.2 +/- 1.0 v 7.6 +/- 0.6 mmol/L, P < .001). Since steady-state plasma insulin concentrations were similar in the two groups (627 +/- 32 v 631 +/- 29 pmol/L), these data indicate that patients with microvascular angina are insulin-resistant, glucose-intolerant, and hyperinsulinemic compared with a matched group of normal volunteers.

Blood Glucose↗
PubMed1989

Treatment of sarcomas of the chest wall using intensive combined modality therapy.

As part of two sequential protocols using intensive combined modality treatment in pediatric and adolescent sarcomas, 31 consecutive patients with primary chest wall tumors were treated between November 1977 and March 1986. This group included 13 patients with peripheral neuroepithelioma (Askin's tumor), 11 patients with Ewing's sarcoma, 3 patients with rhabdomyosarcoma, and 4 patients with undifferentiated sarcomas. Following complete work-up, 17 patients presented with localized disease and 14 patients presented with metastases. Patients received intensive combined modality treatment with combination chemotherapy (vincristine, cyclophosphamide, Adriamycin, +/- actinomycin-D and DTIC) and high-dose conventionally fractionated radiation therapy to the primary (55-60 Gy) and non-pulmonary metastases (45-50 Gy). Radiation techniques used for the primary chest wall tumor varied with the clinical presentation. Patients achieving a complete response received either low-dose fractionated TBI (1.5 Gy/0.15 Gy fx/5 weeks) or high-dose TBI (8 Gy/4 Gy fx/2 days) and an intensive cycle of chemotherapy followed by autologous bone marrow transplantation. Twenty-five of 31 patients were judged to have a complete response (including 1 patient with complete resection). With minimum follow-up of 6 months and median follow-up of 36 months from completion of treatment, 14 patients remain disease-free with 2 additional patients alive in second remission after relapse. Patients with localized disease at presentation have improved disease-free survival and overall survival compared to patients with metastases at presentation. All 17 localized patients achieved a CR and 11 are NED compared to 8 of 14 metastatic patients achieving a CR and only 3 are NED. There have been 5 loco-regional recurrences with 3 "in-field" failures and 2 failures in the regional pleura. There were no treatment-related deaths and no clinically significant cases of pneumonitis. To date, 2 patients have significant treatment related morbidity, including 1 patient with scoliosis requiring surgery and 1 patient with acute leukemia developing 42 months after the start of therapy (presently in remission). We conclude that this intensive combined modality therapy results in a high CR rate and good local control with acceptable morbidity. Patients with metastatic disease at presentation remain a therapeutic challenge.

Adolescent↗
PubMed1989

Putative cocaine receptor in striatum is a glycoprotein with active thiol function.

Dopamine transporters of bovine and rat striata were identified by their specific [3H]cocaine binding and cocaine-sensitive [3H]dopamine [( 3H]DA) uptake. Both binding and uptake functions of bovine striatal transporters were potentiated by lectins. Concanavalin A (Con A) increased the velocity but did not change the affinity of the transporter for DA; however, it increased its affinity for cocaine without changing the number of binding sites. This suggests that the DA transporter is a glycoprotein and that Con A action on it produces conformational changes. Inorganic and organic mercury reagents inhibited both [3H]DA uptake and [3H]cocaine binding, though they were all more potent inhibitors of the former. n-Ethylmaleimide inhibited [3H]DA uptake totally but [3H]cocaine binding only partially. Also, n-pyrene maleimide had differential effects on uptake and binding, inhibiting uptake and potentiating binding. [3H]DA uptake was not affected by mercaptoethanol up to 100 mM, whereas [3H]cocaine binding was inhibited by concentrations above 10 mM. On the other hand, both uptake and binding were fairly sensitive to dimercaprol (less than 1 mM). The effects of all these sulfhydryl reagents suggest that the DA transporter has one or more thiol group(s) important for both binding and uptake activities. The Ellman reagent and dithiopyridine were effective inhibitors of uptake and binding only at fairly high concentration (greater than 10 mM). Loss of activity after treatment with the dithio reagents may be a result of reduction of a disulfide bond, which may affect the transporter conformation.

4-Chloromercuribenzenesulfonate↗
PubMed1988

Enhanced chemiluminescence production by phagocytosing neutrophils in psoriasis.

Using serum-coated zymosan, the generation of reactive oxidants by measurement of chemiluminescence was shown to be significantly enhanced in isolated peripheral psoriatic neutrophils compared to normal controls. This response was observed irrespective of whether zymosan was opsonized with fresh autologous or normal AB serum. However, this increased activity was reduced with zymosan was opsonized with serum that was preheated at 56 degrees C for 30 min. There was no statistical correlation of chemiluminescence activity with degranulation of beta-glucuronidase in either normal or psoriatic subjects. In addition, chemiluminescence produced by normal cells was significantly increased when zymosan was opsonized with psoriatic serum. The plasma membrane-bound enzyme, NAD(P)H oxidase, which produces superoxide in response to phagocytic stimulation, was significantly increased in psoriatic neutrophils compared to normal controls. These data add further evidence for activated neutrophils in psoriasis.

Female↗
PubMed1988

5-Hydroxytryptamine-stimulated inositol phospholipid hydrolysis in the mouse cortex has pharmacological characteristics compatible with mediation via 5-HT2 receptors but this response does not reflect altered 5-HT2 function after 5,7-dihydroxytryptamine lesioning or repeated antidepressant treatments.

5-Hydroxytryptamine (5-HT; 3 x 10(-8)-1 x 10(-5)M) produced a dose-dependent increase in phosphatidylinositol/polyphosphoinositide (PI) turnover in mouse cortical slices, as measured by following production of 3H-labelled inositol phosphates (IPs) in the presence of 10 mM LiCl. Analysis of individual IPs, in slices stimulated for 45 min, indicated substantial increases in inositol monophosphate (IP1; 140%) and inositol bisphosphate (IP2; 95%) contents with smaller increases in inositol trisphosphate (IP3; 51%) and inositol tetrakisphosphate (IP4; 48%) contents. The increase in IP3 level was solely in the 1,3,4-isomer. This response was inhibited by the nonselective 5-HT antagonists methysergide, metergoline, and spiperone. It was also inhibited by the selective 5-HT2 antagonists ketanserin and ritanserin but not by the 5-HT1 antagonists isapirone, (-)-propranolol, or pindolol. 5-HT-stimulated IP formation was also unaltered by atropine, prazosin, and mepyramine. Lesioning brain 5-HT neurones using 5,7-dihydroxytryptamine (5,7-DHT; 50 micrograms i.c.v.) produced a 210% (p less than 0.01) increase in the number of 5-HT2-mediated head-twitches induced by 5-methoxy-N,N-dimethyltryptamine (2 mg/kg). However, 5,7-DHT lesioning had no effect on 5-HT-stimulated PI turnover in these mice. Similarly, an electroconvulsive shock (90 V, 1 s) given five times over a 10-day period caused an 85% (p less than 0.01) increase in head-twitch responses but no change in 5-HT-stimulated PI turnover. Decreasing 5-HT2 function by twice-a-day injection of 5 mg/kg of zimeldine or desipramine (DMI) produced 50% (p less than 0.01) and 56% (p less than 0.01), respectively, reductions in head-twitch behaviour.(ABSTRACT TRUNCATED AT 250 WORDS)

5,7-Dihydroxytryptamine↗
PubMed1985

Serotonergic agonists stimulate inositol lipid metabolism in rabbit platelets.

The metabolism of inositol phospholipids in response to serotonergic agonists was investigated in rabbit platelets. In platelets prelabelled with [3H]-inositol, in a medium containing 10 mM LiCl which blocks the enzyme inositol-1-phosphatase, 5-hydroxytryptamine (5-HT) caused a dose-dependent accumulation of inositol phosphates (IP). This suggests a phospholipase-C-mediated breakdown of phosphoinositides. Ketanserin, a selective 5-HT2 antagonist, was a potent inhibitor of the 5-HT response, with a Ki of 28 nM, indicating that 5-HT is activating receptors of the 5-HT2 type in the platelet. Lysergic acid diethylamide (LSD) and quipazine also caused dose-related increases in inositol phosphate levels, though these were considerably less than those produced by 5-HT. These results show that relatively small changes in phosphoinositide metabolism induced by serotonergic agonists can be investigated in the rabbit platelet, and this cell may therefore be a useful model for the study of some 5-HT receptors.

Animals↗
PubMed1984

A comparison of pulsed ultrasound, radiography and micrometer screw gauge in the measurement of skin thickness.

Comparisons of ultrasonic, radiographic and micrometer methods in the measurement of skin thickness were made in 16 volunteers before and after 1-month's treatment with four clobetasol propionate formulations. Correlations between the methods were highly significant (r = 0.68 to 0.75). Correlations in the females were better than in the males suggesting that measurements in women are more easily made. Percentage reductions in skin thickness after steroid treatment were ranked in an identical order, whichever method was used. Each of the three methods, therefore, was shown to be effective. Ultrasound was the preferred technique but the micrometer screw gauge was shown to be a reasonable alternative.

Adult↗
PubMed1983

Enhanced release of inflammatory mediators from lithium-stimulated neutrophils in psoriasis.

We have used lithium salts to stimulate degranulation in order to assess neutrophil activity in psoriasis. Evidence is presented for significant enhancement of degranulation of beta-glucuronidase (primary granules) and vitamin B12-binding protein (secondary granules) from lithium-stimulated neutrophils in psoriatic whole blood. Basal levels of granule markers showed no significant difference between normal and psoriatic neutrophils. On the other hand, enzymes associated with neutrophil function (myeloperoxidase and catalase) were found to be markedly increased in resting psoriatic neutrophils.

Catalase↗
PubMed1982

Influence of lithium and fluoride on degranulation from human neutrophils in vitro.

We have demonstrated that degranulation from normal human neutrophils in whole blood was stimulated by low concentrations of lithium salts and was produced by noncytolytic means. Significant amounts of beta-glucuronidase could be released from the primary granules, in addition to vitamin B12- binding protein from the secondary granules, by 10 mM lithium. Release was almost totally inhibited by 1 mM fluoride, under the same conditions. There was no release of lactate dehydrogenase and no loss of viability of cells incubated in either lithium or fluoride at the concentrations used. Lithium was also observed to have no effect on reactive oxygen production by phagocytic stimulation of isolated neutrophils. In addition, lithium and fluoride were shown to manipulate the intracellular levels of cAMP. The results demonstrated a direct effect of lithium on release of inflammatory mediators from neutrophils in vitro. The methods used also provide a simple and effective test to study an important function of neutrophil activity and can be used to evaluate degranulation in a number of clinical conditions.

Cyclic AMP↗
PubMed1982

Treatment of chronic plaque psoriasis with dithranol and urea creams: a double-blind study.

Stable cream formulations containing 0.1% or 0.2% dithranol in a 17% urea base have been developed. A double-blind comparative trial in 20 out-patients showed that over a 6-week treatment period the 0.2% dithranol and urea cream was significantly more effective (p less than 0.01) than the 0.1% dithranol and urea cream in clearing chronic plaque psoriasis. The 0.2% dithranol/urea cream was accompanied by a higher incidence of minor, irritant side-effects, but was still well accepted by patients for use at home. The availability of differing strengths of dithranol and urea cream enables practitioners to tailor dithranol treatment in accordance with the individual patient's clinical response.

Administration, Topical↗