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Biomedical subjects

M Zatz

Publications and source records attributed to M Zatz.

At least 181 records · Page 10Linked to original sources
PubMed1988

Relation between height and clinical course in Duchenne muscular dystrophy.

We have evaluated the relation between height and rate of clinical progression in boys with Duchenne muscular dystrophy (DMD). In all, 111 DMD patients with age ranging from 2 to 23 years (mean 8.2 +/- 3.4 years) were assessed; of these patients, 92 had their height measured. Clinical course was determined through Vignos scale of functional disability, motor ability, and timed functional tests. All patients had grossly elevated serum creatine-kinase (CK) and pyruvate-kinase (PK) levels. When height was adjusted for patients' age, a statistically significant correlation was found between height and clinical course (positive with Vignos scale and negative with motor ability), suggesting that smaller boys have a better clinical course than taller patients of comparable age. These results support our previous hypothesis and suggest that growth inhibition seems to be effective in diminishing the progression of DMD.

Age Factors↗
PubMed1988

Genetic and environmental components of serum creatine kinase (CK) and pyruvate kinase (PK) in normal twins: implication for genetic risks estimates in Duchenne muscular dystrophy carriers.

The serum activity of creatine kinase (CK) and pyruvate kinase (PK) was measured in 98 pairs of same-sex Brazilian twins. The purpose of this study was to estimate the genetic and environmental components of serum activity levels for both enzymes. Heritabilities were estimated separately by path analysis in each sex. The results showed that CK and PK activities are under genetic control in normal males and females. Environmental components were not statistically significant for CK or PK. The genetic component of both enzymes estimated in females has implications in the calculation of genetic risks for Duchenne muscular dystrophy carriers.

Creatine Kinase↗
PubMed1988

Effect of mazindol on growth hormone levels in patients with Duchenne muscular dystrophy.

Human growth hormone (HGH) inhibition may be beneficial in Duchenne muscular dystrophy (DMD) and slow down the rate of progression of the disease. The purposes of the present investigation were: 1) to assess, through pharmacological stimuli (L-dopa test), the HGH response in untreated DMD patients, and 2) to evaluate the inhibitory effect of mazindol on HGH levels as a potential treatment for DMD. In 55 DMD patients, HGH levels were measured through the L-dopa test, and 40 received mazindol. After 1 year, there was wide variability in the individual response to mazindol. An apparent diminution in the mean HGH level was observed in the whole group of patients; this was statistically significant after 3 and 6 months but not after 9 and 12 months of treatment. The results suggest that this drug is not effective for arresting growth or inhibiting HGH secretion for a prolonged period of time.

Adolescent↗
PubMed1988

A novel photopigment candidate in membranes of cultured chick pineal cells.

The photopigment of avian pineal which mediates light sensitivity was sought via its chromophore. Chick pineal cells in primary cultures were incubated overnight in the dark with [3H]retinol. Reduction of Schiff's bases with cyanoborohydride prior to SDS-PAGE revealed radioactivity bound to a 30 kDa component in pinealocyte membranes. All-trans-retinal, but not retinol or retinoic acid, incubated with pinealocyte homogenates prior to reduction, resulted in a loss of radioactivity from the 30 kDa region of the gel. The radioactivity was also displaced by NH2OH in the dark. Incubation of cultured cells or homogenates with retinoyl fluoride, an acylating agent specific for the retinal binding site of opsins, also displaced radioactivity from the protein. Furthermore, retinoyl fluoride, added to chick pineal cells in culture, blocked the suppressive effect of light on melatonin output by these cells. Taken together these results raise the possibility that the 30 kDa protein mediates photosensitivity in the chick pineal.

Animals↗
PubMed1988

Effect of thymic hormones on interleukin 2 synthesis by lymphocytes from HIV-positive pre-AIDS subjects.

The PHA-induced synthesis of interleukin 2 (IL-2) by peripheral blood lymphocytes (PBL) from 9 normal and 8 pre-AIDS individuals was evaluated. IL-2 content in supernatant fluids of PBL cultures derived from pre-AIDS patients was only around 20% of that found in normal PBL cultures. The addition of two thymic preparations, thymosin faction 5 and TFX-Polfa, to PHA-stimulated PBL cultures from pre-AIDS patients caused significant increase of IL-2 content in cultures. Thymosin alfa 1 was ineffective in this respect. However, thymic factors corrected only partially the defective IL-2 synthesis by PBL from pre-AIDS patients increasing it to ca. 35% of value for normal PBL. The findings suggest the potential of PBL from pre-AIDS patients to respond in vitro to enhancing activity of thymic hormones.

HIV Seropositivity↗
PubMed1987

Acylation of disc membrane rhodopsin may be nonenzymatic.

Bovine retinal rod outer segments (ROS) support the incorporation of [3H]palmitate into rhodopsin. [14C] Palmitoyl-CoA serves as the donor with an apparent Km of 40 microM. Solubilization of ROS in the detergent, Emulphogene, results in increased incorporation of label into rhodopsin. A further increase is found when ConA-Sepharose-purified rhodopsin is used as the source of both "enzyme" and acceptor. Failure to separate enzyme from acceptor suggested the possibility of a nonenzymatic reaction. This was confirmed when boiled rhodopsin was found to support the reaction. However, the acylation of rhodopsin is not an artifact since analysis of purified native rhodopsin reveals the presence of covalently bound palmitate and we showed that whole bovine retinas incubated with [3H] palmitate incorporated the fatty acid into rhodopsin (O'Brien, P.J., and Zatz, M. (1984) J. Biol. Chem. 259, 5054-5057). Furthermore, in vivo experiments with rat retinas have revealed that opsin is acylated both in the rod inner and outer segments (St. Jules, R. S., and O'Brien, P.J. (1986) Exp. Eye Res. 43, 929-940). Incubation of labeled rhodopsin with mercaptoethanol resulted in release of the labeled palmitate indicating the presence of a thioester bond. This also illustrates the ease with which a thioester, such as palmitoyl cysteine or palmitoyl-CoA, can transfer the fatty acyl group to a free thiol, such as cysteine or mercaptoethanol.

Acylation↗
PubMed1987

Duchenne muscular dystrophy: comparison among different racial groups.

We have compared 232 patients with Duchenne muscular dystrophy belonging to three racial groups: caucasoids, negroids, and mongoloids. Clinical evolution, serum creatine-kinase, and pyruvate-kinase levels were analysed in the three groups. The results of this investigation show that the clinical evolution did not differ significantly among these three racial groups. For serum enzyme activities a statistically significant difference was found only for CK between negroids and mongoloids.

Brazil↗
PubMed1987

Interactions among lithium, calcium, diacylglycerides, and phorbol esters in the regulation of adrenocorticotropin hormone release from AtT-20 cells.

Interactions among lithium, calcium, and phorbol esters in the regulation of adrenocorticotropin hormone (ACTH) release were examined in a tumor cell line (AtT-20) of the anterior pituitary. Lithium, which blocks the phosphatase that converts inositol phosphates (IPs) to inositol, increases the levels of IPs in these cells and stimulates ACTH release. This ion potentiates the ability of calcium, an activator of phospholipase C, to raise levels of IPs in these cells and to stimulate ACTH secretion. Pretreatment of AtT-20 cells with calcium specifically abolishes the ACTH release response to lithium or calcium, a result suggesting that these secretagogues may act through a common mechanism to induce hormone secretion. Prior exposure of AtT-20 cells to either lithium or calcium also attenuates the ACTH release induced by phorbol ester, an activator of protein kinase C. To examine the link among lithium, calcium, phosphatidylinositol (PI) turnover, and phorbol ester-evoked ACTH secretion, AtT-20 cells were treated with 1-oleoyl-2-acetoyl-sn-3-glycerol (OAG), an analogue of the diacylgylcerols that are formed by phospholipase C during PI metabolism and that also activate protein kinase C. OAG itself does not alter ACTH release or the levels of IPs in AtT-20 cells. Pretreatment of AtT-20 cells with OAG, however, selectively blocks the ACTH release response to lithium, calcium, or phorbol ester. Furthermore, such pretreatment reduced the ability of lithium to increase levels of IPs. The results suggest that one mechanism of action of lithium is to potentiate selectively an action of calcium, possibly the stimulation of phospholipase C activity.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1987

Translocation of protein kinase C in anterior pituitary tumor cells.

Previous studies have shown that phorbol esters and lithium each stimulate the secretion of adrenocorticotropic hormone (ACTH) by the anterior pituitary tumor cell line AtT20/D16-16. Pretreatment with either lithium or phorbol ester desensitizes the cells to subsequent stimulation by phorbol ester. An early consequence of phorbol ester action in other systems is the translocation of protein kinase C from cytosol to membranes. We have assayed protein kinase C activity in cytosol and membranes of AtT20 cells after treatment with phorbol dibutyrate, lithium, or other agents that stimulate secretion of ACTH in these cells. Phorbol dibutyrate clearly induced translocation of protein kinase C, but lithium treatment did not cause translocation itself, nor did pretreatment with lithium affect the translocation induced by phorbol dibutyrate. These results are consistent with a role for translocation of protein kinase C in the stimulatory and desensitizing effects of phorbol esters but fail to implicate translocation in the actions of lithium on AtT20 cells.

Adrenocorticotropic Hormone↗
PubMed1987

Dental benefits and reimbursements.

This article analyzes and compares the various dental benefit reimbursement methodologies currently available in the dental marketplace. Emphasis is placed on the advantages and disadvantages of the capitation/HMO approach from the point of view of the patient, dentist, plan administrator, and purchaser/employer.

Capitation Fee↗
PubMed1986

Translocation of protein kinase C in rat hippocampal slices.

Tumor-promoting phorbol esters specifically activate protein kinase C and mimic the effects of neurotransmitters in certain systems. Treatment of hippocampal slices with phorbol dibutyrate caused translocation of protein kinase C activity from cytoplasm to membranes. Experiments with carbachol, norepinephrine, glutamate, KCl, and LiCl failed to demonstrate a similar translocation. Translocation more readily provides an index of protein kinase C involvement for phorbol esters than for other agents in hippocampus.

Animals↗
PubMed1986

Investigation on genetic heterogeneity in Duchenne muscular dystrophy.

The preliminary results of a study to investigate possible genetic heterogeneity in Duchenne muscular dystrophy (DMD) are reported. Ninety-eight patients have been analyzed: 47 were isolated cases; 51 were familial cases. The patients were divided into three groups (normal intelligence, borderline, and mentally retarded) according to mental capacity and a comparison of clinical evolution (onset of clinical signs and loss of ambulation) as well as serum enzyme activities (creatine-kinase and pyruvate-kinase). In addition intrafamilial correlation analysis was done for the same parameters. The preliminary results did not show a significant difference between DMD patients with normal intelligence and those with mental retardation.

Adolescent↗
PubMed1986

Treatment of Duchenne muscular dystrophy with growth hormone inhibitors.

A controlled, double-blind therapeutic trial with the drug mazindol, a growth hormone inhibitor, was performed in a pair of 7 1/2 year-old monozygotic twins, with Duchenne muscular dystrophy (DMD). The rationale for this trial was based on a patient (reported previously) affected simultaneously with DMD and growth hormone (GH) deficiency, who is showing a benign course of the dystrophic process and is still walking at 18 years. One of the twins received 2 mg of mazindol daily, while the other received a placebo. The assessment, repeated every 2 months, included weight and height measurements, functional and motor ability tests, ergometry and determinations of serum enzymes and GH levels. After one year of trial the code was broken and it was seen that the twin under placebo treatment was strikingly worse than his brother, the progression of whose condition was practically arrested. These results strongly suggest that treatment with a GH inhibitor is beneficial for DMD patients.

Body Height↗
PubMed1986

Evaluation of carrier detection rates for Duchenne and Becker muscular dystrophies using serum creatine-kinase (CK) and pyruvate-kinase (PK) through discriminant analysis.

Serum pyruvate-kinase (PK) and creatine-kinase (CK) determinations have been carried out in a sample of 100 obligate carriers for the Duchenne muscular dystrophy (DMD) gene, 23 obligate carriers for the Becker muscular dystrophy (BMD) gene, and 50 normal adult control women. Blood samples were collected from all subjects three times on three independent occasions and the means of these three determinations were considered for both PK and CK activities in the statistical analysis. Discriminant analysis has shown that, in the group of carriers for the DMD gene, the estimated misclassification frequencies (M.F.) using either serum CK, PK, or both enzymes were: 26.5% for CK alone, 19.5% for PK alone, and 19% for both enzymes. In the group of carriers for the BMD gene, the estimated proportions of M.F. were: 31.7% for CK alone, 23.8% for PK alone, and 20.4% for both enzymes. It is concluded that, although a proportion of carries still remains undetected, the use of serum PK determinations enhances the capability of detecting carriers of both DMD and BMD mainly when compared with serum CK alone.

Biometry↗
PubMed1986

Duchenne muscular dystrophy in a girl with a 45,X/46,XX/47,XXX chromosome constitution.

We report on a 4-year-old girl with Duchenne muscular dystrophy (DMD). One of her sisters had grossly elevated serum creatine-kinase and pyruvate-kinase levels, and one of her maternal great uncles was presumptively affected by DMD. Cytogenetic analysis showed a 45,X/46,XX/47,XXX chromosome constitution. The maternally inherited DMD gene is presumed to be present on the single X of the 45,X cell line.

Child, Preschool↗