Biomedical subjects
Publications and source records attributed to J Gross.
The protein content of an individual periodontal ligament fibroblast decreases with increasing cell density during growth in culture. A mean total protein concentration of 3.3 +/- 0.4 micrograms per 10(3) cells was calculated. This reference value can be used in studies evaluating enzyme activities, transport rates or metabolic functions.
The present study examined nicotine replacement effects on postcessation weight gain in smoking cessation clinic volunteers using objective indices of cigarette smoking, gum use, and body weight. After they achieved abstinence, subjects were randomly assigned to either active nicotine or placebo gum conditions for 10 weeks, during which smoking status was carefully monitored. Analyses revealed strong evidence for a gum effect on weight gain, with active gum users gaining a mean total of 3.8 lb compared with 7.8 lb for placebo gum users at the end of the 10-week trial. Evidence for a dose-response relation was found, suggesting that more gum use (greater than or equal to 6.5 pieces/day) resulted in greater weight suppression. Placebo gum subjects reported greater postcessation increases in eating and hunger compared with active gum subjects. The implications of the weight suppression effect of nicotine gum for smoking cessation treatments are discussed.
We identified by a monoclonal antibody-based immunoradiometric assay high concentrations of an exocrine pancreatic protein called pancreatic thread protein (PTP) in several areas of Alzheimer disease (AD) brain. The saline-extractable soluble immunoreactivity shares at least three epitopes in common with the native pancreatic form of the protein; the Mr varies from approximately 17,000 to 20,000. Quantitative measurements of PTP immunoreactivity in various regions of several AD brains revealed levels varying from 12 to 295 ng/g of tissue (mean, 116 ng/g) compared with 1-11 ng/g of tissue (mean, 5 ng/g) found in comparable areas of control brains. Immunocytochemistry performed with the anti-PTP monoclonal antibodies demonstrate PTP immunoreactivity within large pyramidal neurons--many of which contain neurofibrillary tangles in both AD and Down syndrome. Less accumulation was observed in astrocytes, and some PTP immunoreactivity was found extracellularly. The highest number of labeled cells in AD and Down syndrome was seen in the hippocampal formation. Fewer positive-staining cells were noted in normal and disease control brains. We conclude, therefore, that an exocrine pancreatic protein is present in the central nervous system of normal individuals at low levels; in AD brain concentrations of this protein are much higher.
Sleep electroencephalograms (EEGs) of subjects with primary panic disorder were compared to those of normal controls matched for age and sex. Significant differences were found between patients and controls in sleep latency, sleep efficiency, and stage 2 sleep duration. No differences were found between the two groups in REM latency. Because depressed patients are known to have reduced latency to REM sleep, these data add support to the hypothesis that panic disorder and depression are distinct disorders.
We have investigated the relationship between collagenase production, cell shape and stimulatory factors in cell culture. In a homogeneous culture of primary rabbit corneal stromal cells, shape change induced by a variety of agents was not effective in stimulating collagenase secretion. Only in the presence of a biologically active cytokine or phorbol myristate acetate was a correlation seen between changes in cell shape (induced by a second agent) and collagenase secretion by these primary cells. Cell shape changes were not, however, necessary for collagenase secretion, since certain concentrations of endotoxin or lactalbumin hydrolysate effected secretion of the enzyme in the absence of morphological changes. With passaged cells or mixed cell cultures, where cell shape change did correlate with collagenase secretion without the addition of an exogenous agent, the production of an effective cytokine (autocrine or paracrine) was demonstrated. Thus cell shape change seems to be neither universally necessary nor sufficient for the stimulation of collagenase secretion. It is proposed that the function of cytokines may be more immediately related to gene expression in this system than is change in the shape of the cell. The hypothesis is presented that cell shape changes may render the target cells receptive to cytokines, perhaps by replacing the need for a natural cytokine cofactor. It is also demonstrated here that the use of passaged cells, mixed cell cultures containing endogenous cytokine-secreting cells or tissue culture additives can profoundly affect the interpretation of the effect of various agents on collagenase secretion, and may lead to observations that are not directly relevant to cell function in vivo.
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The development of the discipline "Pathological and Clinical Biochemistry" at the Charité hospital from 1963-1983 was described. In the beginning of the sixties new structures for the clinical chemistry were necessary. The role of biochemical diagnostics increased due to the rapid development of the mechanization and automation of clinical chemical analysis. The centralization period of the laboratories of the clinics of the university hospital Charité included two phases: 1963 - foundation of the department of clinical biochemistry of the clinic of internal medicine and 1971 - foundation of the department of clinical biochemistry of the Charité. The main stimulus for the centralization of the laboratories and the foundation of the department of Clinical Biochemistry of the Charité hospital was the increased requests for medical care of the patients. With the new building and the reconstruction of the Charité hospital (1979-1983) the prerequisite were given to establish the discipline as Pathological and Clinical Biochemistry and in form of an institute (1983). The main stimuli for this development were demands to meet all requirements of research, teaching, biochemical diagnostics and pathobiochemical interpretation of biochemical findings of patients.
The effects of hypoxia in adult and newborn rats on the release rate of DA from slices and synaptosomes of striatum were studied. In adult animals hypoxia (10 kPa oxygen tension in the inspiratory air) induces a decrease of the FER of DA from slices up to 70% dependent on the duration of the hypoxia. An early postnatal hypoxia (10 kPa, 2nd -11th day of life) brings about a long-term increase of the FER of DA from slices by about 30% when the release is measured at the age of 2-3 month. Slices show a relatively low release rate compared to synaptosomes. The hypoxia effects found with slices, i.e. a decrease of the FER in adult animals and increase in those that had experienced an early postnatal hypoxia, could not be confirmed in synaptosomes. The much lower release rate from slices suggests the action of inhibitory factors controlling the release of DA. In that case hypoxia would exert an indirect influence.
The effects of hypoxanthine (HX) and xanthine oxidase (XO) on the (3H)-dopamine (DA) uptake into synaptosomes of rat striatum were examined. Preincubation with 20 mU XO and 0.25 mM HX for 10 min diminished the uptake to 55% of controls. Under these conditions no increase of TBARS as an indicator of lipid peroxidation was observed. Kinetic studies revealed that the decrease in DA uptake was related to the high-affinity transport whereas the low-affinity transport carrier remained unaffected. SOD did not influence uptake inhibition, Catalase completely restituted DA uptake at an activity of 50 U. Thus, hydrogen peroxide and the hydroxyl radical appears to be involved in the deleterious action of HX/XO. The effects of this radical generating system seems to be directed to specific sites of biological membranes.
The influence of a hypobaric hypoxia on the dopamine uptake was studied in rat striatum using a concentration range of dopamine from 30 nM to 0.1 mM. Uptake kinetics were calculated by a non-linear regression computer procedure assuming one carrier protein with two binding sites and negative cooperativity. Hypoxia most prominently affected the low affinity uptake site2; a marked increase of Vmax2 was always obtained. This effect seems to be related to the degree of hypoxia and persists for 10 hours at least. For the high affinity uptake site1, a transient decrease of the Vmax1 was apparent but this effect was less reproducible than the alterations of the low affinity uptake site2. These findings are discussed in the context of increased neuronal dopamine release after oxygen deprivation both in vivo and in vitro.
Mild chronic postnatal hypoxia induces a long-lasting increase of DA release from striatal slices in rats. The effect of mild hypoxia on DA and DOPAC concentrations were examined in striata of newborn and adult rats. The short-lasting hypoxia (1 h, pO2 of inspired air was 11.3 kPa) did not change the concentrations of DA and DOPAC neither in newborn nor in adult rats. The long-lasting mild hypoxia (10 h or 17 h) increased the concentrations of DA, decreased that of DOPAC and decreased the turnover of DA turnover. Neither the DA concentration nor DA turnover were altered in striata of adult rats after an exposure to the mild chronic postnatal hypoxia.
Rats after mild chronic postnatal hypoxia always show late sequelae of behaviour and long-term alterations of neurotransmitter release from striatal slices. It was to test preventive or therapeutic actions of drugs using the model of mild chronic postnatal hypoxia of the rat. Pyritinol prevented the learning deficit due to hypoxia and decreases the potassium stimulated DA release from striatal slices. The experiments underline the high plasticity of the CNS during the neonatal period and stress the necessity of early therapy of perinatal brain damage.
To study the influence of gestational age and asphyxia on the behaviour of EDT and ECE a group of cuban control and asphyxiated newborns was investigated. A total number of 203 newborns at the age of 0-3 days of life, all with adequate weight for gestational age, were classified into 4 groups according to their gestational age, the 1 min and 5 min Apgar score and the presence of meconium stained amniotic fluid and/or respiratory distress syndrome immediately after birth. In the group of asphyxiated newborns higher values for both parameters were found when they were compared with the respective control groups (p less than 0.05). These techniques could help the neonatologists to more precisely identify newborns with severe perinatal asphyxia and to improve the prognosis of the outcome.
When we consider pressure sores, we usually think of their location in areas of contact with the bed or chair. However, in the presence of risk factors, any area of skin is subject to breakdown if exposed to constant pressure. This article presents two cases demonstrating unusual locations of pressure sores, and discusses underlying risk factors which contributed to their genesis. Vigilant attention to risk factor intervention by the multidisciplinary care team can prevent the incidence of this common complication of immobility. The use of a standardized risk factor assessment scale can be a useful guide to prevention planning.
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The bladder-emptying status of 85 stroke patients admitted to a comprehensive rehabilitation center was evaluated by postvoid residual (PVR) sequential catheterizations. Those patients with incomplete bladder emptying were assessed by scheduled PVRs throughout their hospitalization. Incomplete bladder emptying occurred initially in 48 of the 85 patients and was sustained in 28. Of this group, 22 were able to void voluntarily and 15 were continent. The incomplete emptying group also demonstrated a significantly higher rate of urinary tract infections. Incomplete bladder emptying or urinary retention in stroke patients with apparently normal bladders is a frequent problem which should be addressed as part of the routine rehabilitation management.
The purpose of this study was to establish if there are any later changes in the local cerebral energy metabolism after exposing 1-day-old rats for 5 days (10 hr daily) to hypobaric hypoxia (pO2 = 10.5 kPa). For this study the 2-[14C]deoxyglucose method for the determination of the regional utilization of glucose in the rat brain was employed. The results, obtained in 41 cerebral structures, show that rats subjected to an early postnatal hypoxia exhibit a significant decrease (-41%) 3 months later in the utilization of glucose in the CA, area of the hippocampus. This finding is a new one in the chain of several biochemical and behavioral changes observed in this experimental model. It is suggested that this finding could be useful in the search for a new therapeutic agent eventually able to alleviate the consequences of perinatal hypoxia.
Normal sera contain an IgM fraction which binds to free galactosyl groups of agarose. This fraction causes complement-dependent lysis of Ehrlich ascites tumor cells (EATC). Cancer sera show a much reduced titer of this lytic activity. In this paper we describe an immunochemical assay for these galactophilins (GALF). Agarose columns were immunoabsorbent and bound proteins were detected by labeled antibody to human IgM. All 157 normal sera contained GALF. The serum GALF concentrations of normal sera were linearly correlated to the serum cytolytic titers. However, EATC absorbed only 15% of normal serum GALF. The titers in normal females are higher than in males. The titers in 147 nonmalignant chronic disease patients were lower than the normals only in women over 40 years of age. The sera of 138 cancer patients, taken before any therapy, were significantly lower than the corresponding normal or chronic disease controls. Lymphoproliferative neoplasms were associated with the lowest titers while melanoma sera showed normal titers. It is likely that GALF is bound to tumor associated antigens with free galactosyl groups. These are on the cell surface and/or are shed into the circulation. GALF titration may prove useful in following treatment efficacy in individual cancer patients.