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Biomedical subjects

M Goldberg

Publications and source records attributed to M Goldberg.

At least 181 records · Page 10Linked to original sources
PubMed1996

Tissue-specific developmental regulation of protein kinase C isoforms.

The limited amount of available information regarding the developmental control of protein kinase C (PKC) isoform expression restricts our understanding of the role of these enzymes in normal physiology. Accordingly, this study investigated PKC isoform expression in selected tissues from fetal, neonatal, and adult rats. PKC beta immunoreactivity was prominent in brain tissue, whereas the expression of PKC alpha, PKC delta, PKC epsilon, and PKC zeta was found to be widespread. Although no developmental change in any PKC isoform was evident in liver, striking tissue-specific age-dependent differences in PKC isoform abundance were noted in other tissues. For example, age-dependent increases in PKC alpha, PKC beta, and PKC delta in brain contrasted with age-dependent decreases in PKC alpha and PKC delta in lung, kidney, and heart. Immunoreactivity for PKC epsilon was abundant in all fetal/neonatal tissues; PKC epsilon was detected in the adult brain, heart, and liver, but not the adult kidney and lung. Finally, PKC zeta was more abundant in fetal/neonatal than in adult brain, lung, kidney, and heart. These results indicate that the fetal/neonatal lung, kidney, and heart are enriched in PKC zeta, PKC alpha, PKC delta, and PKC epsilon, relative to the adult tissues. These age-dependent variations in the abundance of individual isoforms of PKC may critically influence tissue responsiveness to external stimuli. Moreover, the finding that PKC zeta is particularly abundant in fetal tissues as well as the liver, the only tissue included in this study which retains regenerative capacity in the adult animal, is consistent with the notion that PKC zeta may play a role in cell proliferation.

Age Factors↗
PubMed1996

Dual incorporation of (35S)sulfate into dentin proteoglycans acting as mineralization promotors in rat molars and predentin proteoglycans.

Autoradiographic investigations were carried out 0.5, 1, 2, 4, 24, 48, 72, and 120 hours after the injection of a single dose of [35S]-sulfate on undemineralized molars of 7-15-day-old rats. In predentin, labeling was detected at 0.5 hours. Silver grain density reached a plateau value between 1 and 24 hours, then decreased and disappeared 120 hours after injection. In dentin, the mineralization front started to be labeled as early as 0.5 hours after injection. Labeling increased at the dentin edge between 1 and 2 hours, reached a maxima at 4 hours, then started to decrease, the labeled band seen 24 hours after injection being further incorporated into dentin. This band stood at constant distance from the dentin-enamel junction with stable grain density, even at 120 hours. This investigation proves the existence of two distinct groups of [35S]-labeled proteoglycans, one exclusively related to predentin and disappearing with time, and the second one located in dentin behaves as a stable component. The fact that an early labeling appeared at the mineralization front which was further incorporated into dentin, confirms that dentin proteoglycans constitute an individual group of molecules that are not derived from predentin proteoglycans, and act as mineralization promotors.

Animals↗
PubMed1996

Morphological study of amelogenesis in the rat lower incisor after thyro-parathyroidectomy, parathyroidectomy and thyroidectomy.

The effects of thyro-parathyroidectomy, parathyroidectomy or thyroidectomy upon enamel formation in the rat incisor were studied. One control group and four groups of surgically treated rats were used: parathyroid autotransplanted, thyroidectomized, parathyroidectomized, and thyro-parathyroidectomized. One month after surgery, the incisors were processed for light and electron microscopy. The present study revealed perturbations of the Tomes process morphology, of the rod pattern in the inner enamel formation, of the enamel surface, and of the mineralization after thyro-parathyroidectomy. After parathyroidectomy, only mineralization defects could be visualised. No effects were observed in enamel after thyroidectomy. A severe hypocalcemic state as seen in thyro-parathyroidectomized rats affects the enamel shape, and mineralization, and the morphology and function of secretory ameloblasts. Knowledge of the way in which the alteration of the enamel surface is produced should contribute to a better understanding of the development of tooth enamel.

Ameloblasts↗
PubMed1996

Time-trend of sleep disorder in relation to night work: a study of sequential 1-year prevalences within the GAZEL cohort.

We examined two longitudinal hypotheses: the 1-year prevalence for night workers is consistently higher than for others; the time trend is steeper for night workers than for others. Subjects were 12,779 men (age 40-50) working at Electricité de France-Gaz de France, and recruited in the GAZEL cohort. Five questionnaires were sent to all subjects on 1989 through 1993. Self-reported occurrence of sleep disorder in the previous year was regressed on night work status in 1989 and covariates to estimate prevalence rate differences (PRDs). The estimated PRD for regular night workers versus others was 6.1% (95% CI, 1.1-11.1%). There was a common time trend of 1.4% per year (1.0-1.9%), and evidence of excess trend for regular night workers: 1.1% (-0.7-2.9%). Findings indicate that the effect of night work on sleep complaints manifests itself during the first year of night work and is permanent.

Adult↗
PubMed1996

Improved accuracy of burn wound assessment using laser Doppler.

The utility of the laser Doppler for determining burn depth has been questioned because of problems with technology and methodology. This study prospectively evaluates the ability of a new laser Doppler technique to predict burn healing time. Using the Periflux System 4000 laser Doppler, readings were taken on 305 burns (147 patients) on postburn day 3 or 4. Sixty-six wounds were used to derive a predictive function (phase I) and 152 wounds were used to test the function (phase II). Blood flow dynamics (flux), microvascular dilation capacity of the wounds to beat stress, and flow motion wave pattern (vasomotion) were studied using the laser Doppler, and seven parameters were evaluated to determine their relative contribution to the prediction of healing time. These parameters are hyperemic flux (flux value after heating to 42 degrees C), average hyperemic wave amplitude (AHWA), number of average flux units >100(F100), number readings with wave amplitude 75 (A5), average flux change (AFC), percentage of average flux increase, and relative flow capacity (RFC = AFC/average hyperemic flux). After readings were made, the wounds were observed and divided into two groups: those that healed in less than 14 days and those that healed or were grafted after 14 days. A step-wise discriminant analysis was used to assess the relative contribution of the Doppler-derived measures to healing time prediction. AHWA, F100, and RFC were included in the final discriminant function explaining 72% of the healing time variance (Wilks' lambda value 0.28; p value <0.0001). Predicted outcome = 0.05(AHWA) + 0.31(F100) + 5.0(RFC) - 2.3. With this derived function, there is 94% accuracy in the prediction of burn wound healing time compared with a physician predictive accuracy of 70%.

Adolescent↗
PubMed1996

Studies and comparison of pterin patterns in the plasma of dogs and cats and their alteration in various neoplasias and virus infections.

Physiological pterin levels were evaluated in plasma samples of healthy dogs and cats. Biopterin and 7-xanthopterin were determined quantitatively by HPLC after partial purification by ion exchange chromatography. Neopterin, pterin and 6-hydroxymethylpterin were not detectable in plasma samples. Pterin levels in plasma of dogs with neoplasias and cats with neoplasias or viral infections (FeLV, FIV, FIP) were determined. Dogs with various tumours did not show qualitative but distinct quantitative alterations in the pterin concentration in plasma. Biopterin concentrations in plasma of dogs after tumour exstirpation significantly decreased compared to the levels before surgery. There was only a moderate increase of the biopterin levels in plasma of cats with neoplasias in comparison to healthy animals of this species. Cats suffering from viral infections, however, showed a significant rise in biopterin concentrations. The results underscore the importance of pterins as sensitive indicators for the presence of activation of cell mediated immune response. With emphasis on biopterin the role of pterins as helpful parameters for the preventation and the monitoring of diseases is pointed out.

Animals↗
PubMed1996

A comparative study of the transition between predentin and dentin, using various preparative procedures in the rat.

The appearance of the junction between predentin and dentin of rat incisors was investigated after chemical fixation (aldehyde), physical fixation (high pressure freezing and freeze substitution) and by histochemistry. Physical fixation revealed a 1-2 micron wide intermediary zone, in which only the collagen fibers were mineralized. In dentin, which looked denser and more homogeneous, both collagen fibers and intercollagenous spaces were mineralized. The intermediary layer could not been seen after aldehyde fixation. When cationic dyes were used during fixation in order to retain proteoglycans, a 0.5-5 micron border zone located at the junction between predentin and dentin was densely stained on the dentin side, whereas in dentin only the interglobular network displayed electron density. The periodic acid-thiocarbohydrazide-silver proteinate reaction, visualizing glycoproteins, and the phosphotungstic acid/chromic acid mixture, which reveals glycoproteins and phosphorylated proteins, produced extensive staining of the transitional zone located at the dentin edge, whereas staining was weaker in dentin. These morphological and histochemical investigations support the existence of an intermediary zone in which mineralization occurs. This transitional zone between predentin and dentin has specific properties; therefore we propose it be termed metadentin.

Aldehydes↗
PubMed1996

Failure of early postnatal dexamethasone to prevent chronic lung disease in infants with respiratory distress syndrome.

OBJECTIVE: To study the effect of early postnatal dexamethasone (days 1-3) on the incidence and severity of chronic lung disease in preterm infants with respiratory distress syndrome. METHODS: A multicentre, randomised, placebo controlled, blinded study was carried out in 18 neonatal intensive care units in Israel. The primary outcome measure was survival to discharge without requirement for supplemental oxygen therapy beyond 28 days of life. The secondary outcome measures were requirement for mechanical ventilation at 3 and 7 days, duration of ventilation or oxygen therapy, need for subsequent steroids for established chronic lung disease and incidence of major morbidities. RESULTS: The study consisted of 248 infants (dexamethasone n = 132; placebo n = 116). No differences were found in the outcome variables except for a reduction in requirement for mechanical ventilation at age 3 days in treated infants (dexamethasone 44%, placebo 67%; P = 0.001). Gastrointestinal haemorrhage, hypertension, and hyperglycaemia were more common in treated infants, but no life threatening complications, such as gastrointestinal perforation, were encountered. CONCLUSIONS: These data do no support the routine use of early postnatal steroids, but may justify further study in a selected, high risk group of infants.

Birth Weight↗
PubMed1996

Anaplastic large cell Ki-1 lymphoma: primary bone presentation in an elderly man.

Ki-1 anaplastic large cell lymphoma (Ki-1 ALCL) is a recently recognized entity. Primary presentation in the bone is very rare. Very few cases of primary bone presentation have been reported. All previous reported patients were children and young adults, usually with multiple bone involvement. We report a case of a 60-year old man who presented with extensive mixed blastic and lytic lesions in one tibia, simulating osteogenic sarcoma radiographically, with regional lymphadenopathy. Further studies showed this tumor to be a B cell Ki-1 ALCL. Tumor cells stained positive for Ki-1 antigen (CD30), leukocyte common antigen (CD45), vimentin, and L26 (CD20), negative for cytokeratin, S100, Leu M1 (CD15). The patient was treated with combination chemotherapy and local radiation, with an excellent initial response.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Radioautographic study of the incorporation of (3H)-choline into the phospholipids of secretory ameloblasts and enamel of normal and essential-fatty-acid-deficient rats.

(3H)-choline, a precursor for phosphatidylcholine (PC) and sphingomyelin (SM), was injected into rats killed after 4, 24, 48, and 96 hrs. Radioautography carried out on malachite-green/aldehyde-fixed tissues demonstrated that labeled choline was incorporated into cells and further released into the extracellular matrix. In predentin, labeling decreased rapidly, whereas in dentin, silver grains formed a stable band. In contrast, labeling was still high at 48 and 96 hrs in secretory ameloblasts as well as in the forming enamel. This indicates that ameloblasts are actively involved in the synthesis of membranes. Membrane remnants of the ameloblasts could be released into the forming enamel. In rats fed with an essential fatty-acid-deficient (EFAD) diet for 42 days, (3H)-choline uptake was delayed and reduced in pulp cells and odontoblasts, and consequently the migration of labeled phospholipids into dentin. The influence of the EFAD diet on secretory ameloblasts was limited. No difference was detected between normally fed and EFAD-fed rats in the forming enamel.

Ameloblasts↗
PubMed1996

Effects of accelerated eruption on the enamel of the rat lower incisor.

The effect of accelerated eruption of the rat lower incisor on enamel was studied in a series of segments obtained when the incisor was cut repeatedly out of occlusion over a five-week period. The segments were ground, cleaned, acid-etched, observed with SEM, and analyzed with EDX. Pigmentation was lost within 11 days. Pigmented superficial enamel was more acid-resistant than the rest of the enamel, but this quality decreased with decreasing iron content. Hypomineralized enamel first appeared in a restricted area at the mesio-labial angle of the tooth in the 6th-7th segment obtained after 11-14 days. Later, hypomineralization became more generalized. All enamel zones were retained throughout the experiment. The geometry of the prism pattern was affected. The angle between prism rows and the enamel-dentin junction increased from 44 degrees to 48 degrees, while the angle of decussation increased from 60 degrees to 70 degrees. The angle between the enamel surface and prisms in the outer enamel was more difficult to assess, but tended to increase from about 25 degrees to 29 degrees. However, the prisms retained their incisal direction. The connection between enamel and dentin was partly disrupted from about the 9th segment onward. The depth of the mesial concavity of the enamel-dentin junction decreased from about the 10th segment onward. Accelerated eruption affects all stages of enamel formation and is a suitable and predictable model for studying regulatory mechanisms in amelogenesis.

Ameloblasts↗
PubMed1996

Work conditions and mental health among prison staff in France.

OBJECTIVES: A cross-sectional epidemiologic survey was conducted among prison staff in France to investigate the relationships between work conditions and mental health. METHODS: The sample included men and women 20 to 64 years of age belonging to all categories of prison personnel (prison guards, administrative staff, socioeducational workers, technicians, health care workers, and managers). A postal self-administered questionnaire was used to assess sociodemographic factors, work conditions, and physical and mental disorders. Multiple logistic regression analyses were conducted to determine the effects of work conditions and social relationships on the mental health of prison staff. RESULTS: The results presented in this report only concern depressive symptomatology (measured by the French version of the Center for Epidemiologic Studies Depression Scale), anxiety (measured by the state version of the State-Trait Anxiety Inventory), and sleep disorders. The percentage of mental disorders was higher among prison staff than that determined for other occupational samples. Guards comprised the prison staff least affected by these symptoms. CONCLUSIONS: The results show that, in our sample, the factors concerning the subjective evaluation of work conditions and social support were more closely related to mental disorders than work conditions. In addition, seniority was associated with depressive symptoms and anxiety among the men.

Adult↗
PubMed1996

Selective visualization of choroidal neovascular membranes.

PURPOSE: Laser-targeted angiography has unique advantages over conventional angiography of the fundus. Its efficacy in visualizing choroidal neovascular membranes was tested in a rat model and compared to that of fluorescein angiography. METHOD: Laser-targeted angiography was performed in rats with choroidal neovascularization (CNV) by injecting heat-sensitive carboxyfluorescein liposomes intravenously, locally releasing a bolus of dye in the choroid with a weak laser pulse, and recording advancement of the bolus on a video camera. Conventional fluorescein angiography also was performed. RESULTS: Laser-targeted angiography revealed CNV as an abnormal pattern of brightly fluorescent vessels. The flow pattern of the bolus and histology, performed in some cases, confirmed the choroidal nature of the vessels. The angiographic visualization was not dependent on dye leakage through the vessels or staining of their walls. Laser-targeted angiography also provided visualization of new vessels that could not be diagnosed by fluorescein angiography. It demonstrated that blood flow was typically more sluggish in CNV than in normal choriocapillaris. Fluorescein angiography failed to demonstrate flow dynamics in all cases of CNV. CONCLUSIONS: This study, in an animal model of CNV, shows that laser-targeted angiography demonstrates CNV and its flow dynamics in a manner not provided by conventional fluorescein angiography. It holds clinical promise as a method to delineate CNV considered difficult or impossible to detect by fluorescein angiography. The method also may permit selective photocoagulation of feeding vessels in the choroid, thereby limiting damage to the overlying retina.

Animals↗