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Biomedical subjects

A Maier

Publications and source records attributed to A Maier.

At least 127 records · Page 7Linked to original sources
PubMed1989

Contours and distribution of sites that react with antiacetylcholinesterase in chicken intrafusal fibers.

Serial cross and longitudinal sections of intrafusal fibers from the intracapsular portions of chicken tibialis anterior muscle spindles were incubated with a monoclonal antibody specific for chicken acetylcholinesterase (AchE) and examined by immunofluorescence for the presence of the enzyme on presynaptic and postsynaptic membranes of neuromuscular junctions. The midequatorial sensory region which lacks organized sarcomeres was negative, but immediately distal to it faintly staining regions of AchE localization were observed on intrafusal fibers. In cross sections at the juxtaequator, the outlines of areas that were positive for AchE were either thin and crescentlike or thick and compact. The distribution of both types of localization continued into the polar region. Toward the more distal polar region, the intensity of sites on the postsynaptic membrane that reacted with the anti-AchE progressively increased. In longitudinal sections, AchE localization was largely limited to two configurations. One was elongate, while the other was more round or oval and often also smaller. Both types might occur on the same, or on different, intrafusal fibers. Examination of silver-impregnated sections revealed the presence of platelike and of traillike axon terminals. The variety of shapes observed on presynaptic and postsynaptic membranes warrants further study to determine whether chicken muscle spindles are innervated by more than one type of motor neuron.

Acetylcholinesterase↗
PubMed1989

Reactivity of rat and rabbit intrafusal fibers with monoclonal antibodies directed against myosin heavy chains.

Serial cross and longitudinal sections from the intracapsular portions of intrafusal fibers of rat and rabbit tibialis anterior muscles were examined by fluorescence microscopy with a library of monoclonal antibodies directed against different epitopes on myosin heavy chains. Intrafusal fiber types were identified with the histochemical reactions for acid-stable and alkali-stable actomyosin ATPase. Three antibodies, known to react with avian heart and slow-tonic myosins, produced fluorescent staining in intrafusal fibers. Nuclear bag2 fibers reacted with all three antibodies, chain fibers with two, and nuclear bag1 fibers with only one. These results indicate that in rat and rabbit tibialis anterior muscle spindles nuclear bag2 fibers and chain fibers contain more than one myosin isoform. They also demonstrate that, in addition to the histochemical actomysin ATPase reaction, nuclear chain fibers and the two types of nuclear bag fibers can be identified by the selective reactivities of their myosin heavy chains.

Animals↗
PubMed1989

Expression of the small cell carcinoma antigens of cluster-5 and cluster-5A in primary lung tumours.

The expression of the small cell carcinoma (SCLC) antigens cluster-5 (antibody LAM8) and cluster-5A (antibody SWA20) was examined on a panel of routinely processed biopsy or surgical specimens of 290 lung tumours by immunoperoxidase staining. Antigen expression was largely restricted to SCLC. Of over 150 tissue samples evaluated, moderate or strong antigen expression was found in 49% (cluster-5) and 45% (cluster-5A). Concordance in expression of the two antigens was seen in 71% of SCLC samples, with 35% expressing both antigens strongly, 8% moderately and 28% being negative for both antigens. Antigen expression was independent of the morphological subtype of SCLC. Primary lung tumours of other histology, including squamous cell carcinoma, large cell carcinoma, adenocarcinoma, mesothelioma or carcinoid had no significant antigen expression. Of 135 tumours, strong or moderate expression of both antigens was seen only in two cases. 20%, mostly carcinoids, were weakly positive for cluster 5 and 4% for cluster 5A antigen. The remainder were antigen negative. No significant antigen expression was seen in 25 normal lung tissues. The membrane antigens of SCLC cluster 5 and 5A are markers for SCLC and their expression in tissues is tumour-associated.

Antigens, Neoplasm↗
PubMed1989

[Sonography of gallbladder carcinoma. Correlation with surgical findings in 60 cases].

60 patients with carcinoma of the gallbladder were staged preoperatively by sonography (staging scheme by Nevin and TNM scheme of the UICC). This was correlated with the operative and histopathological findings. The tumour was diagnosed by sonography in 70% of the patients, 15% were diagnosed at operation and 15% histopathologically. The criterion for malignancy was tumour invasion into the liver (94.7% Sensitivity) and/or into adjacent tissues (36.8% Sensitivity). Most tumours were in an advanced stage (98.5%) and only one early carcinoma (1.5%) was found histopathologically. No improvement in the diagnosis of early carcinomas was achieved by ultrasound in our series.

Adult↗
PubMed1989

[Multiple elemental organic components of the broncho-alveolar lavage fluid in normal subjects and in various lung pathologies (excluding silica and asbestos fibers)].

Owing to a technical analysis enabling the detection of mineral elements present in trace amounts in small volumes, an analysis of the liquid obtained in 148 broncho-alveolar lavages could be studied. The elements consistently recovered were as follows: iron, copper, zinc, nickel, lead and titanium. Normal values were established. In the absence of exposure, there was no significant difference distinguishing the different pulmonary diseases studied. In occupational disease, the presence of iron in large quantities, tungsten, nickel and rare earths could be shown objectively, as well as the persistence of gold or iodine after medical absorption. However, this preliminary work does not allow one to establish a formal correlation between the alveolar concentrations obtained and the pulmonary disease observed.

Adolescent↗
PubMed1988

A combined histochemical and immunohistochemical study on the dynamics of fast-to-slow fiber transformation in chronically stimulated rabbit muscle.

Chronically stimulated fast-twitch muscles of the rabbit were histochemically and immunohistochemically analyzed in serial cross sections (1) for percentages of fiber types, and (2) for the presence of myosin heavy chain isoforms during fast-to-slow transformation. By four weeks of stimulation the number of type-I fibers had increased more than fourfold, while only about 6% of the original IIB fibers remained. Type-IC and -IIC fibers transiently rose to 20% of the total fiber population. After 16 weeks, the number of type-I fibers had increased to 42%. With prolonged stimulation fewer fibers reacted with antibodies against embryonic and neonatal myosins and more with the antibody against slow myosin. The reaction for embryonic myosin was most often detected in the C fibers (IC, IIC). Immunohistochemical subtypes were observed for each fiber type in the stimulated muscles. The greatest number was seen in type-IIC fibers, which, in addition to their reaction for fast/neonatal and slow myosins, might also react with the antibodies against neonatal/embryonic and embryonic myosins. These findings indicated that the transforming fibers temporarily expressed myosin heavy chain isoforms normally not detectable in adult skeletal muscle. Myotubes reacted strongly with the antibodies against fast/neonatal and embryonic myosins, and some of them also with the antibody against slow myosin. Thus, it appears that under the influence of the low frequency stimulus pattern some of the newly formed myotubes developed into type-I fibers.

Animals↗
PubMed1988

Immunohistochemical demonstration of embryonic myosin heavy chains in adult mammalian intrafusal fibers.

Serial cross sections of rat, rabbit and cat intrafusal fibers from muscle spindles of normal adult hindlimb muscles were incubated with a monoclonal antibody against embryonic myosin heavy chains. Intrafusal fiber types were identified by noting their staining patterns in adjacent sections incubated for myofibrillar ATPase after acid or alkaline preincubation. In rat and rabbit muscle spindles dynamic nuclear bag1 fibers reacted strongly at the polar and juxtaequatorial regions. Static nuclear bag2 fibers reacted weakly or not at all at the polar region, but showed a moderate amount of activity at the juxtaequator. At the equatorial region both types of nuclear bag fibers displayed a rim of fluorescence surrounding the nuclear bags, while the areas occupied by the nuclear bags themselves were negative. Nuclear chain fibers in rat and rabbit muscle spindles were unreactive with the specific antibody over their entire length. In cat muscle spindles both types of nuclear bag fibers presented profiles which resembled those of the nuclear bag fibers in the other two species, but unlike in rat and rabbit spindles, cat nuclear chain fibers reacted as strongly as dynamic nuclear bag1 fibers.

Adenosine Triphosphatases↗
PubMed1988

Distribution of sarcoplasmic reticulum Ca-ATPase and of calsequestrin at the polar regions of rat, rabbit and cat intrafusal fibers.

Sarcoplasmic reticulum (SR) Ca2+-pumping ATPase (Ca-ATPase) and calsequestrin (CaS) were visualized by indirect immunofluorescence at the polar regions of adult rat, rabbit and cat intrafusal fibers. The immunohistochemical reaction products were regarded as histochemical markers of the SR and as valid indicators of the distribution of the two Ca2+-sequestering proteins. Static nuclear bag2 fibers displayed lower levels of both Ca-ATPase and CaS than the other two intrafusal fiber types. Nuclear chain fibers presented the highest Ca-ATPase levels and, together with dynamic nuclear bag1 fibers, they also exhibited relatively high amounts of CaS. The level of Ca-ATPase was lower in bag 1 fibers than in nuclear chain fibers, but not as low as in bag2 fibers. The comparatively high levels of Ca-ATPase and CaS seen in nuclear chain fibers coincided with their reported faster contractile speeds compared to nuclear bag fibers.

Animals↗
PubMed1987

Distribution of connective tissue proteins in chick muscle spindles as revealed by monoclonal antibodies: a unique distribution of brachionectin/tenascin.

The distribution of chick muscle spindles of eight connective tissue proteins (collagen types I, IV, V, and VI, laminin, heparan sulfate, fibronectin, and brachionectin/tenascin) was examined by immunofluorescent histochemistry. Intrafusal fibers were surrounded by layers of collagen type VI and fibronectin, and by an external lamina containing collagen type IV, laminin, and heparan sulfate. Most of these layers displayed a different pattern of staining at the sensory region of the equator than at the polar region. The crescent-like sheath that caps each intrafusal fiber and sensory terminal at the equator was strongly positive for collagen type I and weakly positive for collagen type V. The outer spindle capsule contained laminin, heparan sulfate, collagen types IV and VI, brachionectin/tenascin, fibronectin, and to a lesser degree also collagen types I and V. Brachionectin/tenascin had the narrowest distribution of any of the connective tissue macromolecules studied. It was found only in the outer capsule and in the coverings of blood vessels and nerves associated with the outer capsule.

Animals↗
PubMed1987

The time course of glycogen depletion in single fibers of chronically stimulated rabbit fast-twitch muscle.

A time course study was conducted to investigate the possibility of a relationship between fiber degeneration and glycogen depletion in chronically nerve-stimulated extensor digitorum longus muscle of the rabbit. Muscles were stimulated 12 h daily at 10 Hz using alternating one-hour periods of stimulation and rest. When measured for the first time after 3 h (1 h stimulation, 1 h rest, 1 h stimulation), microphotometry revealed complete glycogen depletion of all fiber types (fast glycolytic, FG; fast oxidative glycolytic, FOG; slow oxidative, SO). Different responses were noted beginning at day 4. At this time point, all FOG and SO fibers recovered their glycogen stores with some of the FOG population attaining levels higher than the FOG fibers in the unstimulated, contralateral muscle. Approximately 28% of the FG fibers recovered to normal glycogen values, whereas 58% remained depleted and 14% displayed "overshooting glycogen" levels. Fifteen percent of all fibers were glycogen-depleted after 12 days of stimulation. At this time, classic fiber types could no longer be distinguished. Fiber degeneration, which was recognized by the invasion of nonmuscle cells, began after 6 days and was restricted to the glycogen-depleted fibers. By this time, there was also a significant increase in DNA content. Exhaustion of glycogen, the main fuel of the FG fibers, is believed to cause a collapse of energy-supply and ATP-driven ionic pumps. The latter could be the initial step of fiber deterioration.

Animals↗
PubMed1987

[Uninodular bronchiolo-alveolar cancer. Apropos of 5 cases with a prolonged course].

Five cases of uninodular bronchioloalveolar cell (BAC) carcinoma are reported. These 5 cases were characterized by the protracted course of the disease: 14.5 and 11.5 years respectively in the 2 patients who died; 7.5, 12 and 12.5 years respectively in the 3 patients who are still alive. Prior to being diagnosed at excision, the tumours had been followed up for an unusual 2 to 10 years period, with phases of radiological stability and phases of very slow growth. This very slow course is exceptional in lung cancer. It differs not only from the course of diffuse BAC carcinoma, but also from the habitual course of uninodular BAC carcinoma and from that of peripheral adenocarcinoma. Similar cases could be found in the literature, and a comparative study has been conducted between these slow-course carcinomas and normal-course carcinomas. Whatever their outcome, slow-course carcinomas are asymptomatic tumours which present at radiography of the chest as a peripheral round or oval opacity devoid of pathognomonic features. The post-operative prognosis of slow-course tumours seems to be more favourable than that of the other lung cancers. At histology, carcinomas with a protracted course usually show a pattern similar to that of lesions called by some authors "benign adenomatosis"; however, some of these tumours exhibit fairly distinct signs of malignancy, and electron microscopic images also are far from being uniform.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1987

Simultaneous determination of trace elements in lavage fluids from human bronchial alveoli by energy-dispersive x-ray fluorescence. 3. Routine analysis.

We applied the energy-dispersive x-ray fluorescence technique to determination of trace elements in human bronchoalveolar lavage fluids. Our analysis of more than 200 samples allowed us to determine normal reference values, to be used in characterizing occupational exposure. These values are expressed both in nanograms per 1000 cells (of all kinds) and nanograms per 1000 macrophages to correlate lavage efficiency and dust content of the alveoli. The result expressed in milligrams per liter is not sufficient, because some healthy volunteers showed high concentrations of iron but normal values when expressed vs the number of cells. Some examples of abnormal compositions of broncho-alveolar lavages are reported and the fully automated spectrometer developed for clinical and biological investigations is described.

Bronchoalveolar Lavage Fluid↗
PubMed1986

Relation between the frequency of colorectal adenoma and the serum cholesterol level.

Several investigators have reported an association between low serum cholesterol levels and an increased frequency of colorectal cancer. Because low cholesterol levels may be a result of an established cancer, we have investigated the relation between serum cholesterol levels and the frequency of colorectal adenomas, which are thought to be precursors of colon cancer. We prospectively studied 1083 consecutive patients who underwent colonoscopy (241 of whom were excluded because of malignant disease, chronic inflammatory bowel disease, familial polyposis, or partial colectomy). In the remaining 842 patients, analysis of covariance was performed to evaluate the contribution of serum cholesterol to the risk of colorectal adenoma. Serum cholesterol levels were significantly and positively associated with the frequency of colorectal adenoma in subjects of both sexes. After adjustment for age and body-mass index, this positive association remained significant between the top quintile and the lowest quintile for serum cholesterol, with regard to the total study group (odds ratio, 2.0; 95 percent confidence limits, 1.1 and 3.6) and men only (odds ratio, 2.2; 95 percent confidence limits, 1.0 and 4.8). We conclude that there is not an inverse correlation between serum cholesterol levels and the risk of colorectal adenomas; on the contrary, there appears to be a small positive association.

Adenoma↗
PubMed1986

Degeneration-regeneration as a mechanism contributing to the fast to slow conversion of chronically stimulated fast-twitch rabbit muscle.

Extensor digitorum longus muscles of male adult White New Zealand rabbits were indirectly stimulated at 10 Hz for 12 h daily for periods ranging up to 28 days. After four weeks the stimulated muscles showed a nearly uniform profile of high succinate dehydrogenase activity and, when incubated after acid preincubation for myofibrillar adenosine triphosphatase, displayed more dark- and intermediate-staining fibers than their contralateral counterparts. Muscles stimulated from between 6 to 21 days revealed degenerative foci and phagocytosis of degenerated fibers. These fibers were mostly of the fast-twitch, glycolytic type. Small myofibers, which often contained central nuclei, and structures identified as myoblasts or myotubes, reacted with a monoclonal antibody prepared against embryonic myosin heavy chains. The data suggest that under the employed conditions the fast to slow conversion of chronically stimulated fast-twitch rabbit muscle is not exclusively caused by adult fiber transformation, but results in part from the substitution of fast-twitch glycolytic fibers with newly formed fibers that have a high oxidative profile.

Adenosine Triphosphatases↗
PubMed1986

Distribution of sarcoplasmic reticulum Ca-ATPase and of calsequestrin in rabbit and rat skeletal muscle fibers.

Muscle fibers in rabbit extensor digitorum longus (EDL), tibialis anterior (TA) and soleus, and rat soleus, were examined immunohistochemically for two proteins of the sarcoplasmic reticulum. Ca-ATPase and calsequestrin (CaS). Fibers were typed with the histochemical reaction for actomyosin ATPase. In the rabbit EDL and TA, type I fibers clearly reacted less for Ca-ATPase and CaS than type II fibers, but the difference was less with CaS than with Ca-ATPase. Although the differences were relatively small, IIB fibers consistently presented greater amounts of Ca-ATPase than IIA fibers. No type II subgroups could be recognized after incubation with anti-CaS. These findings confirm results from previous immunochemical measurements on whole muscles containing different proportions of IIA and IIB fibers (Leberer and Pette 1986). Type IIA and IIC in the rabbit and rat soleus reacted stronger for Ca-ATPase and for CaS than type I fibers. Small differences in Ca-ATPase, but not in CaS, were recognized within the type I fiber population. Therefore, type I fibers in the rabbit and rat soleus are not a homogeneous population.

Animals↗
PubMed1986

Simultaneous determination of trace elements in lavage fluids from human bronchial alveoli by energy-dispersive x-ray fluorescence. 2: Determination of abnormal lavage contents and verification of the results.

We applied energy-dispersive x-ray fluorescence to the determination of abnormally present elements or abnormal concentrations of elements in human broncho-alveolar lavage fluids. The low detection limits and the ability to perform multi-elemental analysis permit one to establish or confirm occupational exposure of workers. We also describe different methods used to check our method and our results. We report examples of abnormal compositions of broncho-alveolar lavages containing W, Ce, La, Nd, I, Fe, or Ni. We discuss the limits of the method for characterizing silicosis or asbestosis.

Asbestosis↗