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Biomedical subjects

G Vogel

Publications and source records attributed to G Vogel.

At least 199 records · Page 11Linked to original sources
PubMed1990

A new method of bacterial identification using gold immunolabelling and scanning electron microscopy.

This study sought to develop an immunolabelling technique to identify specific bacteria by scanning electron microscopy. Bacterial suspensions were prepared of Actinobacillus actinomycetemcomitans, Porphyromonas (Bacteroides) gingivalis and mixtures of these species with other genera of common oral microorganisms. This method was also used to examine subgingival plaques from 6 subjects with chronic adult periodontitis. Sample preparation consisted of prefixation of the bacterial suspensions with 0.2% glutaraldehyde, incubation with species-specific rabbit antisera and goat anti-rabbit IgG conjugated with colloidal gold particles, postfixation in 2% glutaraldehyde and dehydration in ethanol. Finally, the samples were dried, coated with evaporated carbon and examined by scanning electron microscopy. Pure cultures and artificial mixtures of A. actinomycetemcomitans and Bact. gingivalis were specifically labelled by gold probes as demonstrated by both secondary and back-scattered imaging. These species were also evident in samples of subgingival plaque. The findings indicate that this new technique can be used to identify specific microorganisms both in plaque samples and on the root surface of extracted teeth.

Actinobacillus↗
PubMed1990

Decreased intracranial self-stimulation in a new animal model of endogenous depression.

Neonatal treatment of rats with clomipramine may produce adult animals which model endogenous depression. We report here that a major factor of depression in humans, the diminished capacity for pleasure, appears present in these rats. At age 7 months, bar-press responding for rewarding hypothalamic stimulation is reduced across a range of intensities. At age 4 or 5 months this effect is not seen, although other behavioral abnormalities are present at the younger age. The delayed onset of diminished intracranial self-stimulation may relate to the gradual insidious onset of endogenous depression in humans.

Animals↗
PubMed1990

Procedure- and age-dependent hyperactivity in a new animal model of endogenous depression.

We have replicated the findings of Mirmiran and colleagues that neonatal administration of the antidepressant clomipramine (CLI) to male rats results in hyperactivity in open-field tests in adulthood. We report that this effect does not reliably occur in a "Digiscan" activity device. The difference in effect between the two activity measuring devices may be due to more stress being present in the open-field test, and we propose that the CLI-treated rats may be more reactive to stress. This hypothesized enhanced reactivity to stress may be similar to the proposed vulnerability of depressed humans to stress. In addition, we have found that the open-field effect does not occur until the rats are at least 4 months old; this delayed effect may be analogous to the progressive onset of endogenous depression in humans.

Aging↗
PubMed1990

Diminished sexual activity in a new animal model of endogenous depression.

Our laboratory has proposed a new animal model of endogenous depression. The proposal is that in rats neonatal clomipramine (CLI) produces adult animals that model endogenous depression. Diminished sexual activity is a salient behavioral abnormality found in endogenous depression. This suggests that an animal model of endogenous depression should show diminished sexual activity. We report here a test of the prediction that after neonatal treatment with CLI, adult male rats show decreased sexual activity. We found that after neonatal CLI, adult male Long-Evans rats had a pervasive diminution of sexual activities including decreased mounts, intromissions, ejaculations, and increased mount latencies and postejaculatory pause. Sprague-Dawley and Wistar strains also tended to show decreased intromissions and ejaculations, but their baseline sexual activity was too low to give interpretable data. The results with the sexually active Long-Evans strain are consistent with the hypothesis that neonatal CLI produces adult rats that model human endogenous depression.

Animals↗
PubMed1990

REM sleep abnormalities in a new animal model of endogenous depression.

Endogenous depression has reliable REM sleep abnormalities. These include a short REM latency, frequent sleep onset REM periods, and after REM sleep deprivation (RSD), an abnormal temporal course of REM rebound in the presence of a normal total REM rebound. The reliability of these abnormalities suggests that they ought to be present in an animal model of endogenous depression. In 1982, we proposed a new animal model of endogenous depression. Our hypothesis is that in rats neonatal clomipramine (CLI) will produce adult animals that model endogenous depression. In this study we tested the prediction that after neonatal treatment with CLI, adult rats will show the above three REM sleep abnormalities of human endogenous depression. We found that neonatal treatment with CLI produced rats that at age 6 months had shorter REM latency, more sleep onset REM periods than control rats, and after RSD, had an abnormal temporal course of REM rebound in the presence of a normal total REM rebound. The finding of these REM sleep abnormalities supported the validity of the animal model of endogenous depression.

Animals↗
PubMed1990

A new animal model of endogenous depression: a summary of present findings.

In 1982 our laboratory proposed a new animal model of endogenous depression. The proposal was that in rats, neonatally administered clomipramine (CLI) will produce adult animals that model endogenous depression. We summarize here several tests of the validity of the model. Results were that after neonatal CLI, adult male rats showed behavioral abnormalities of the human disorder: decreased sexual, aggressive, and intracranial self-stimulation activities, as well as motor hyperactivity in a stressful situation. Preliminary evidence suggested that behavioral abnormalities in rats (sexual, aggressive, and motor) briefly treated with antidepressant treatments (imipramine, REM sleep deprivation) begin to normalize. Lastly, after neonatal CLI, the adult rats showed REM sleep abnormalities of endogenous depression, viz, low REM latency, frequent sleep onset REM periods, and abnormal temporal course of REM rebound after REM sleep deprivation. These results supported the hypothesis that in rats neonatal CLI produced adult animals that modelled endogenous depression.

Animals↗
PubMed1990

The chronic efficacy of midazolam.

The chronic efficacy of midazolam 15.0 mg was studied in 2 male and 10 female subjects. Only subjects with a complaint of sleep latency insomnia which was verified by polysomnography were included in the study. Following a screening and adaptation period, subjects spent 3 consecutive nights in the laboratory during the weeks of the study. Placebo was administered 15 min before lights out on the initial 8 and final 2 nights, and midazolam for the intervening 35 nights. Midazolam significantly reduced sleep latency parameters and significantly increased total sleep time the entire 5 weeks of nightly administration. No within-night rebound insomnia, residual daytime effects, or rebound effects upon discontinuation appeared.

Adult↗
PubMed1990

Pharmacokinetics of fluoride in man and its clinical relevance.

A large number of parameters will influence and mediate the activity and the pharmacological response of dental fluoride products after systemic or topical treatment. This report reviews some aspects of the pharmacokinetics of fluoride in man, fluoride bio-availability, plasma kinetics, and kinetics of fluoride in saliva and plaque fluid. Pharmacokinetic studies in growing dogs show that 90% of a single injected fluoride dose is retained shortly after birth, but at maturity it decreases to about 50%. The degree of fluoride accumulating in calcifying tissues seems to be strongly related to age. The bio-availability of fluoride from swallowed fluoride toothpaste is shown to be decreased if the toothpaste is ingested close to a meal. Several studies show that fluoride exerts its cariostatic effects through the liquid phase surrounding the enamel. The importance of fluoride in the fluid environment of the teeth and the kinetics of fluoride in saliva are discussed. Clinical studies using different slow-release fluoride systems indicate that they are promising cariostatic agents--in particular intra-oral slow-release devices and lozenges. A new micro-analytical method to study the kinetics of fluoride in plaque fluid collected from single tooth sites has been developed. Preliminary studies show that the clearance of fluoride from plaque fluid is slowest in the upper incisor region, followed by the molar region, and faster in the lower incisor region. A site-by-site study of the concentration of fluoride in plaque fluid after topical fluoride administration could be extremely beneficial in optimization of the methods and recommended safety regimens for fluoride therapy.

Biological Availability↗
PubMed1990

Identification of Actinobacillus actinomycetemcomitans by gold immunolabeling and scanning electron microscopy.

Recent evidence suggests that dental plaque is not a homogeneous bacterial mass but, on the contrary, specific bacterial morphotypes and species may be preferentially located within certain microenvironments. The aim of the present study was to develop combined gold immunolabeling and scanning electron microscopic (SEM) techniques for the identification of periodontal pathogens in subgingival dental plaque and on the root surfaces of extracted teeth. Suspensions of pure A. actinomycetemcomitans cultures or suspensions of A. actinomycetemcomitans mixed together with other oral bacteria were prepared, labeled with goat anti-rabbit IgG conjugated with 5 nm or 40 nm colloidal gold particles, and observed by SEM using both secondary and back-scattered imaging. Scanning electron microscopy demonstrated that the A. actinomycetemcomitans bacterial cell surface was specifically labelled. There was no cross-reaction with any of the other bacterial morphotypes. Only the labeled A. actinomycetemcomitans were visible in mixtures examined by back-scattered imaging scanning electron microscopy. The combined techniques of gold immunolabeling and SEM may, therefore, be useful in identifying A. actinomycetemcomitans in subgingival plaque samples and on the root surfaces of extracted teeth as well as in studies of bacterial ecology in dental plaque, in general.

Actinobacillus↗
PubMed1990

Dose effects of temazepam in transient insomnia.

A transient insomnia model, the "first night" effect in the sleep laboratory, was used to assess the dose range for the hypnotic and sleep stage effects of temazepam. 201 healthy, normal subjects (97 men and 104 women), 21 to 49 years old, with no sleep complaints were studied. Each was randomly assigned to receive either placebo, 7.5, 15, or 30 mg temazepam hard gelatin capsules (Restoril) administered double-blind 30 min before bedtime on their first night in the sleep laboratory. Over the 8-h polysomnogram total sleep time and sleep efficiency increased significantly in a linear fashion with increasing doses of temazepam. Sleep tendency was significantly reduced by increasing doses again in a linear manner. Wake time during the sleep period was reduced significantly only by the higher dose. The percentage of stage 1 sleep was reduced and the percentage of stage 2 sleep was increased, each linearly with increasing doses. These data are the first to demonstrate the hypnotic effects of a 7.5 mg dose of temazepam and also support previous studies of 15 and 30 mg temazepam administered to chronic insomniacs. They also illustrate the utility of the "first night" effect as a model of transient insomnia.

Adult↗
PubMed1989

mRNAs for plasma membrane calcium pump isoforms differing in their regulatory domain are generated by alternative splicing that involves two internal donor sites in a single exon.

cDNA clones coding for human plasma membrane Ca2+ pump isoforms have been isolated from a fetal skeletal muscle cDNA library. Compared with the sequence of a teratoma cDNA-encoded pump these clones specify isoforms that contain either 29- or 38-amino acid insertions within the calmodulin-binding region. Replacement of two basic arginine residues by an aspartic acid and a glutamine residue could influence the binding of calmodulin to these isoforms. RNase mapping shows that RNA species containing the 29-residue-encoding insertion are particularly abundant in skeletal muscles. The sequences coding for the insertions are present on a single 154-base-pair exon, as demonstrated by an analysis of the corresponding genomic region, and they are included in their respective mRNAs by alternative splicing involving the differential usage of two internal "cryptic" donor splice sites in the presence of a nearby canonical one. Inclusion of the complete 154-base-pair exon results in an mRNA coding for a pump protein with a shorter C-terminal amino acid sequence that lacks a consensus site for phosphorylation by the cAMP-dependent kinase. Exclusion, inclusion, or partial inclusion of the same exon can thus lead to the production of four different mRNAs from a single gene. When expressed as protein, these mRNAs encode Ca2+ pump isoforms that differ in their C-terminal regulatory domains.

Adult↗
PubMed1989

Periodontitis in a patient with chronic neutropenia.

The aim of this investigation was to obtain information about the composition and the morphology of the microorganisms that inhabit the root surface of a patient with chronic neutropenia and severe and progressive periodontitis. In addition, gingival biopsies were studied by both scanning and transmission electron microscopy (SEM and TEM) to look for bacteria within the gingiva. Dark field microscopy (DFM) revealed 50% spirochetes, 30% motile rods, and 20% coccoid forms. Fourteen extracted teeth studied by SEM showed that the distribution of different bacterial morphotypes varies along the root surface and spirochetes are the prevailing bacteria on the most apically located plaque. TEM analyses of gingival tissue revealed no bacterial invasion within the gingiva. This study suggests that spirochetes may play an important role in the etiology of periodontitis associated with chronic neutropenia. In spite of neutropenic status, there was no bacterial invasion into the gingiva, suggesting that host reaction to dental plaque has not been abolished in this condition.

Adult↗
PubMed1989

Two-site immunochemiluminometric assay of intact human parathyrin in serum with use of a tracer peptide purified by reversed-phase high-performance liquid chromatography.

For this two-site immunochemiluminometric assay of intact human parathyrin (hPTH), the luminescent tracer was synthetic hPTH(53-84), conjugated via succinimide linkage to (aminobutyl)ethyl-isoluminol hemisuccinimide (abei-h). Purification of the labeled hPTH(53-84) by reversed-phase high-performance liquid chromatography allowed isolation of the conjugate having the highest incorporation of abei-h, 1.6 mol per mole of hPTH(53-84). The solid-phase antibody directed against the N-terminal part of hPTH was immobilized by adsorption onto the polystyrene surface of the assay tube and extracted the intact hPTH and N-terminal fragments. Another antibody against synthetic hPTH(53-84), which bound to the C-terminal part of intact hPTH, was indirectly labeled at its second free binding site with the abei-h-labeled hPTH(53-84). The assay has a detection limit of 0.5 pmol/L; it is accurate, precise, and reliable; and it shows a linear response for samples containing up to 100 pmol of hPTH per liter. The normal reference interval ranged from 1.8 to 5.9 pmol/L; 56 patients with primary hyperparathyroidism had concentrations ranging from 5.9 to 113 pmol/L. The concentrations detected in patients with idiopathic hypoparathyroidism were below the normal reference interval.

Chromatography, High Pressure Liquid↗
PubMed1988

Clinico-pharmacological studies with recombinant hirudin.

The pharmacokinetics of recombinant hirudin were studied in 9 healthy subjects after single intravenous, subcutaneous or intramuscular doses of 0.1 mg/kg. Generally, administration of r-hirudin was tolerated without side effects. An assay was used which detects the inhibitor in blood and urine by its antithrombin activity. Absorption, distribution and elimination of r-hirudin were found to be corresponding to the results obtained with native hirudin. The effects on the haemostatic system were evaluated. Thrombin time and partial thromboplastin time were prolonged dependent on the r-hirudin plasma level. Platelet counts, fibrinogen level and fibrinolytic system were unchanged. Bleeding time was not prolonged. After administration of r-hirudin in case of chronic DIC, fibrinogen level, platelet counts and fibrin monomers transiently returned to normal values.

Adult↗
PubMed1988

Treatment of coronary heart disease by diet and exercise: fasting and diurnal lipoproteins.

The effects of a combined exercise and low-fat dietary regimen were studied in 11 patients with angiographically documented coronary heart disease (cholesterol 233 mg/dl, triglycerides 158 mg/dl) and 13 comparable patients (cholesterol 224 mg/dl, triglycerides 174 mg/dl) on usual care. During one year, fasting serum lipoproteins were lowered to "ideal" levels in the intervention group (cholesterol 191 mg/dl, triglycerides 100 mg/dl, LDL-cholesterol 121 mg/dl). There was no change of triglycerides and cholesterol on usual care while LDL-cholesterol rose significantly. Neither regimen had any effect on HDL-cholesterol. Diurnal triglycerides as a presumptive measure of IDL in the intervention group were diminished by 39%. The study demonstrates the feasibility of a diet and exercise regimen to normalize mildly elevated plasma lipid levels and thus to possibly affect the course of coronary heart disease without drugs.

Cholesterol↗
PubMed1988

Complete primary structure of a human plasma membrane Ca2+ pump.

cDNAs coding for a plasma membrane Ca2+ pump were isolated from a human teratoma library and sequenced. The translated sequence contained 1,220 amino acids with a calculated molecular weight of 134,683. All regions of functional importance known from other ion-transporting ATPases could be identified. The translated sequence also contained, near the carboxyl terminus, the calmodulin-binding domain and two domains which are very rich in glutamic acid and aspartic acid. These two domains resemble calmodulin somewhat and one of them may play a role in the binding of Ca2+. The enzyme also contains domains rich in serine and threonine, one of which has a sequence matching those of good cAMP-dependent protein kinase substrates. The carboxyl-terminal region is important for regulation by calmodulin, proteolysis, and phosphorylation. Near the amino terminus are two domains which are very rich in lysine and glutamic acid, as well as two domains resembling EF hands, one of which also has some resemblance to calmodulin. Comparison of the cloned sequence with peptide sequences from the erythrocyte Ca2+ pump showed that the two proteins have a very high proportion of identical residues but are not 100% identical, indicating that they represent different isozymes.

Amino Acid Sequence↗