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PubMed1997

Quantitative studies of chicken somatotrophs during growth and development by morphometry, immunocytochemistry, and flow cytometry.

Changes in the male chicken somatotroph during growth and maturation have been examined by morphometric and immunocytochemical (ICC) analysis of serial sections of the anterior pituitary gland and by flow cytometry of dispersed anterior pituitary cells. ICC showed that somatotrophs are confined to the middle and caudal thirds of the anterior pituitary gland at all ages from 5 to 26 weeks. At a given age somatotrophs are of equal size at all positions along the cephalocaudal axis of the anterior pituitary gland. However, there are age-related changes: from 5 to 11 weeks rises occur in both the mean total somatotroph volume per gland (64%) and the mean number of somatotrophs (78%), while the mean volume of the single somatotroph is unchanged. From 11 to 18 weeks the mean volume of the single somatotroph decreases 41%. From 18 to 26 weeks the mean volume of the somatotroph, the mean total somatotroph volume, and the mean number per gland do not change. Flow cytometry studies suggested that somatotrophs from adults have less growth hormone (GH) than somatotrophs from young birds. The increases in total somatotroph volume and number from 5 to 11 weeks are consistent with the rise in anterior pituitary GH reported previously. Basic quantitative morphological information about age-related changes in somatotrophs is reported here. When combined with additional facts from future work, they may explain the well-documented sharp decline in circulating GH from 5 to 11 weeks.

Aging↗
PubMed2000

GH secretion in TRH-refractory and TRH-responsive chickens is independent of somatotroph abundance and morphometry.

Chicken pituitary glands chronically exposed (for 2-4 h) to growth hormone (GH) secretagogues in vitro have increased GH secretion and increased numbers of GH-secreting cells. In contrast, thyrotropin-releasing hormone (TRH)-induced GH release in chickens in vivo is only transitory and cannot be maintained by constant infusion or repeated serial iv administration. The possibility that this reflects changes in somatotroph abundance, morphology, and GH content was therefore examined in chickens responsive or refractory to TRH in vivo. TRH-induced GH release was immediately (within 10-30 min) followed by a reduction in the size and number of immunoreactive pituitary somatotrophs and in the size of somatotroph clusters, resulting in a reduction in somatotroph area. The number and area of the immunoreactive GH-secreting cells was further reduced 60 min after the bolus administration of TRH, although control values were restored after 120 min. The decline in immunoreactive somatotroph number and size was attenuated by serial TRH injections, but this did not restore plasma GH responsiveness in TRH-refractory birds. These results demonstrate that somatotroph responses to GH secretagogues in vivo differ from those in vitro.

Animals↗
PubMed1994

Nuclear morphometry as a predictor of response to neoadjuvant chemotherapy plus radiotherapy in locally advanced cervical cancer.

We have studied nuclear morphometric characteristics from H & E slides of 23 patients with locally advanced squamous cell carcinoma of the cervix treated with neoadjuvant chemotherapy (cis-platinum + 5-fluorouracil) plus radiation therapy to see if a correlation existed between these morphometric assessments and response to chemotherapy/radiotherapy. On the same 23 patients, biopsies were taken at three times: before treatment, after chemotherapy alone, and after chemotherapy plus radiation therapy. Using the Zeiss Videoplan III morphometric workstation, tumor nuclear area and nuclear roundness factor were assessed on three different tumor cell populations: the basal, intermediate, and superficial cell layers. There were two principal results from this study: (1) There was a significant (P = 0.007) reduction in the appearance of the basal layer of tumor cells following chemotherapy. (2) The reduction in nuclear area of intermediate layer tumor cells by chemotherapy alone was significant in responders (P = 0.005) but not in nonresponders (P = 0.74) to the combined therapy. The ability to differentiate between responders and nonresponders to combined therapy after only the chemotherapy has been administered may allow more rational patient selection for radiation therapy.

Adult↗
PubMed1996

Cardiac injury by activated leukocytes: effect of cyclooxygenase and lipoxygenase inhibition evaluated by electron microscopical morphometry.

Leukocytes can take part in an inflammatory response in the heart after myocardial infarction or cardio-thoracic surgery. To investigate the injurious mechanism of activated polymorphonuclear leukocytes (PMN), isolated rat hearts were perfused with phorbol 12-myristate 13-acetate (PMA) activated PMN (3 x 10(6)/ml) alone for 10 min, in combination with a mixture of oxygen free radical scavengers (superoxide dismutase+catalase+thiourea) or in combination with ibuprofen (IBU), a cyclooxygenase inhibitor or diethylcarbamazine (DCM), a lipoxygenase inhibitor or BW 755C, a dual inhibitor of cyclooxygenase and lipoxygenase and an oxygen free radical scavenger. After 30 min of recovery, the hearts were perfusion-fixed with glutaraldehyde for electron microscopical examination. Based on examination of 25 micrographs per heart obtained by a random sampling procedure and on morphometric methods, volume fractions (Vv) of mitochondria (mito), altered mitochondria (alt mito), myofilament, and cellular edema were measured as fractions of myocyte volume. The most important finding was that Vv(alt mito/myocyte) was 0.09 +/- 0.16 and 0.02 +/- 0.04 in the hearts receiving PMN+PMA alone and when scavengers were added, respectively, whilst no changes in mitochondrial ultrastructure was observed after addition of IBU, BW 755C or DCM. Vv(mito/myocyte) was for PMN+PMA alone: 0.33 +/- 0.04, +scavengers: 0.29 +/- 0.02 +IBU:0.29 +/- 0.02, +BW 755C: 0.23 +/- 0.03*, +DCM: 0.28 +/- 0.02 (mean +/- S.D., *P < 0.05 compared to PMN+PMA). Capillary wall volume (cap wall) as a fraction of the whole capillary was also quantified. Vv(cap wall/cap) was for PMN+PMA alone: 0.26 +/- 0.06, +scavengers: 0.22 +/- 0.03, +IBU: 0.19 +/- 0.04*, +BW755C: 0.21 +/- 0.03, +DCM: 0.15 +/- 0.04* (*P < 0.05). These results further strengthen the notion that activated PMN are intravascularly active. In addition to exerting a cardiodepressive effect the present study shows that activated PMN can induce structural changes in the heart through the combined action of oxygen free radicals and arachidonic acid metabolites.

Animals↗
PubMed1995

Morphometry and histochemistry of pulmonary arteries in a hypoplastic lung model.

Persistent pulmonary hypertension (PPH) is a common consequence of many neonatal respiratory diseases. The pathophysiology of PPH remains unknown. To study PPH, a rat model of pulmonary hypoplasia was used. Lung mass and body mass were recorded and lungs were prepared for frozen section examination and stained with hematoxylin and eosin, elastin, anti-Factor VIII, and nitro blue tetrazolium to identify nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase. The lungs were analyzed for air space volume, pulmonary artery wall thickness, total pulmonary arterial cross-sectional area, and density of tissue NADPH diaphorase staining. The mass of hypoplastic lungs was less than that of normal lungs (mean mass 85.93 mg vs 142.97 mg, P < 0.0001). The measured fraction of airspace volume was significantly less in hypoplastic lungs compared to controls (17.7% vs 30.8%, P < 0.0001). There was a significant difference in the pulmonary artery wall thickness ratio between the two groups (control 0.46 vs hypoplastic 0.487, P = 0.001). The arterial cross-sectional area was identical (control 1.25% vs hypoplastic 1.37%, P = 0.47). Staining density for NADPH diaphorase activity was determined using an intensity staining index (ISI). The experimental group showed increased staining for NADPH diaphorase (ISI = 54 in hypoplastic lungs vs 38 in controls, P < 0.01). Lung mass, appearance, and measured volume of airspace and tissue were all consistent with hypoplasia. In this model, arterial wall thickness was measurably greater in the hypoplastic group, while arterial cross-sectional area was not different. Staining for NADPH diaphorase showed significantly greater levels of enzyme in the hypoplastic lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Sexual dimorphism in the corpus callosum: methodological considerations in MRI morphometry.

Studies of sexual dimorphism in the corpus callosum (CC) have employed a variety of methodologies for measurement and normalization but have yielded disparate results. The present work demonstrates how in some cases different manipulations of the same raw data, corresponding to different commonly used methodologies, produce discordant results. Midsagittal CC area was measured from magnetic resonance images (MRIs) of 137 young normal volunteers. Three strategies intended to normalize for average differences in brain size between the sexes, as well as five different normalization variables, were contrasted and evaluated. The stereotaxic method normalizes for intersubject differences in overall brain size by scaling MRIs into a standardized space. The ratio method uses one of five different indices of brain size and divides it into CC area. The covariate method uses one of the indices as a covariate in statistical analyses. Male subjects show significantly larger absolute total area, as well as anterior third and posterior midbody. However, in two of three normalization strategies, namely the stereotaxic and ratio methods, females show relatively larger total area, anterior midbody, and splenium. The covariate method did not show any significant differences at the 0.05 level. Results suggest that different approaches to normalization and analysis are not necessarily equivalent and interchangeable.

Adult↗
PubMed2001

A unified statistical approach to deformation-based morphometry.

We present a unified statistical framework for analyzing temporally varying brain morphology using the 3D displacement vector field from a nonlinear deformation required to register a subject's brain to an atlas brain. The unification comes from a single model for structural change, rather than two separate models, one for displacement and one for volume changes. The displacement velocity field rather than the displacement itself is used to set up a linear model to account for temporal variations. By introducing the rate of the Jacobian change of the deformation, the local volume change at each voxel can be computed and used to measure possible brain tissue growth or loss. We have applied this method to detecting regions of a morphological change in a group of children and adolescents. Using structural magnetic resonance images for 28 children and adolescents taken at different time intervals, we demonstrate how this method works.

Adolescent↗
PubMed2001

Voxel-based morphometry using the RAVENS maps: methods and validation using simulated longitudinal atrophy.

Statistical analysis of anatomical maps in a stereotaxic space has been shown to be a useful tool in population-based studies for quantifying local anatomical differences or changes, without a priori assumptions about the location and extent of the regions of interest. This paper presents an extension and validation of a previously published methodology, referred to as RAVENS, for characterizing regional atrophy in the brain. A new method for elastic, volume-preserving spatial normalization, which allows for accurate quantification of very localized atrophy, is used. The RAVENS methodology was tested on images with simulated atrophy within two gyri: precentral and superior temporal. It was found to accurately determine the regions of atrophy, despite their localized nature and the interindividual variability of cortical structures. Moreover, it was found to perform substantially better than the voxel-based morphology method of SPM'99. Improved sensitivity was achieved at the expense of human effort involved in defining a number of sulcal curves that serve as constraints on the 3D elastic warping.

Atrophy↗
PubMed2003

Very high-resolution morphometry using mass-preserving deformations and HAMMER elastic registration.

This article presents a very high-resolution voxel-based morphometric method, by using a mass-preserving deformation mechanism and a fully automated spatial normalization approach, referred to as HAMMER. By using a hierarchical attribute-based deformation strategy, HAMMER partly overcomes limitations of several existing spatial normalization methods, and it achieves a level of accuracy that makes possible morphometric measurements of spatial specificity close to the voxel dimensions. The proposed method is validated by a series of experiments, with both simulated and real brain images.

Adult↗
PubMed1995

Age, gender, and hemispheric differences in human striatum: a quantitative review and new data from in vivo MRI morphometry.

We reviewed postmortem and neuroimaging studies of striatal neuroanatomy in humans. The quantitative review revealed evidence of moderate age-related shrinkage of the caudate nucleus and the putamen and consistent leftward asymmetry of the globus pallidus. The data on sex differences were very sparse. We examined neostriatal structures in two samples (healthy volunteers and patients with negative radiological findings) using in vivo magnetic resonance imaging. In both samples, bilateral age-related shrinkage of the caudate nucleus was found, although among the patients the effect was significant only for males. The putamen was measured only in the second sample, and age-related reduction in its volume was found also only among males. A trend for rightward asymmetry in the volume of caudate nucleus was observed in both samples, although it reached statistical significance only among the patients. Putative pathological and physiological mechanisms underlying the observed differences in teh neostriatum are discussed.

Adolescent↗
PubMed2001

Relationship of airway responsiveness with airway morphometry in normal and immunized rabbits.

Airway responses to chemical stimuli occur over a wide range of concentrations, with overlap between severe, moderate and mild asthmatic groups and with normal healthy individuals. Mathematical modelling has suggested that relative thickness of the airway wall may account for this range of responsiveness. We have investigated whether in vivo airway responsiveness varies as a function of airway wall thickness in terms of airway smooth muscle area in normal and immunized New Zealand White (NZW) rabbits. Airway responsiveness to inhaled methacholine (MCh) was determined in vivo under neuroleptanalgesia. Subsequently, ex vivo responsiveness to MCh (pD(2)=-log EC(50)) of isolated bronchi from the same animal was established. Smooth muscle area per mm basement membrane (SM/mmBM) was also measured morphometrically in the tested bronchi and the findings related to in vivo and ex vivo responsiveness. We found no relationship between airway responsiveness in vivo and pD(2)values in either immunized or control rabbits. In both control and immunized rabbits, no correlation was found between SM/mmBM and in vivo airway responsiveness. Only in immunized animals with a PCA titre >0, was there a significant correlation (=-0.5986, P<0.05) between SM/mmBM and pD(2). We conclude that airway smooth muscle area per se is not the sole contributor of airway responsiveness in vivo in normal rabbits.

Animals↗
PubMed1997

Toluene disrupts outer hair cell morphometry and intracellular calcium homeostasis in cochlear cells of guinea pigs.

The aromatic hydrocarbon, toluene, has been demonstrated to disrupt auditory system function both in occupational epidemiological and in laboratory animal investigations. This agent, along with several other organic solvents, impairs hearing preferentially at middle frequencies-a finding that distinguishes these agents from the traditional high-frequency impairment observed with ototoxic drugs such as aminoglycoside antibiotics and cisplatin. Prior investigations have identified the outer hair cell as a probable target for toluene exposure, although studies designed to evaluate spiral ganglion cell impairment have not been reported. The purpose of this investigation was to determine directly whether outer hair cells isolated from the guinea pig cochlea show morphological alterations consistent with a toxic response to toluene exposure. Since slow adjustments of outer hair cell length can result from alteration in free intracellular calcium concentration, the effect of toluene on calcium homeostasis was monitored in both outer hair cells and spiral ganglion cells. A dose-response relationship was observed in the extent of outer hair cell shortening produced by toluene with a significant shortening observed at concentrations of 100 microM and higher. By contrast, the nonototoxic solvent, benzene, produced little shortening at 100 microM to 1 mM concentrations. Studies of calcium homeostasis conducted using the fluorescent probe, Fura-2, showed that toluene enhanced free intracellular calcium levels of both outer hair cells and spiral ganglion cells within 5 min of exposure at concentrations of 30 microM and higher. Intracellular calcium levels were elevated only slightly following benzene administration at 1 mM, but not at lower concentrations. Cells cultured in artificial perilymph nominally containing no calcium and those to which EGTA was added still showed a maximal increase in intracellular calcium level when treated with toluene. These data indicate that the elevation in free intracellular calcium levels produced by toluene results from release of calcium from intracellular stores.

Animals↗
PubMed1994

Morphometry of the size of the capillary-to-fiber interface in muscles.

Capillary-to-fiber perimeter ratio is a morphometric estimate of muscle capillarity in transverse sections which accounts for the three-dimensional arrangement of the capillary network. We compared different methods for estimating capillary-to-fiber perimeter ratio in muscles with large differences in fiber size and capillary density or geometry (hummingbird and bat flight muscle, bat hindlimb, tuna red muscle and rat M. soleus). There was no significant difference between light and electron microscopy estimates of capillary-to-fiber perimeter ratio by direct intersection-counting in transverse sections. Calculated values via capillary surface per fiber volume and fiber cross-sectional area/perimeter were not significantly different from those obtained by direct intersection-counting in muscle transverse sections in any muscle. A closer estimate of capillary-to-fiber perimeter ratio to that obtained by direct intersection-counting in transverse sections was calculated via capillary surface density than capillary length per fiber volume and capillary diameter, possibly because of the greater number of variables used to calculate capillary-to-fiber perimeter ratio via capillary length density and diameter. A greater capillary-to-fiber perimeter ratio was found in hummingbird and bat flight muscle than in the other muscles, consistent with an important role of the capillary-to-fiber interface in determining O2 flux rates and measurements of mitochondrial respiratory rates in flying hummingbird that are about two times greater than those in locomotry muscles of mammals running at VO2max.

Animals↗
PubMed1995

Morphometry of the optic nerve and retinal vessels in children by computer-assisted image analysis of fundus photographs.

BACKGROUND: The retinal fundus in childhood has a different morphology than in adulthood. Existing methods are not suitable for evaluation of fundus photographs from children. Therefore, a new method for quantitative analysis of fundus morphology utilizing a personal computer-assisted digital mapping system was developed. METHODS: A CCD flatbed scanner is used to digitize fundus photographs, producing computer images which are analyzed on an IBM/AT computer. Area measurements of the optic disc, excavation and peripapillary crescent are made, as well as determinations of the length, branching, tortuosity and distribution of the retinal vessels on the fundus surface. RESULTS: Determination of the inter- and intra-observer variability of the computer-assisted image analysis technique demonstrated good reproducibility. The method is demonstrated using fundus photographs of six normal children and six children with the fetal alcohol syndrome. Typical variations in appearance of optic disc and retinal vessels are seen. CONCLUSION: The system is unique in measuring both the optic nerve head and the retinal vessels and is therefore especially useful for detailed studies of normal and abnormal development of these structures in children.

Adolescent↗
PubMed1996

Morphometry, scanning electron microscopy and X-ray spectral microanalysis of protostylid pits on human lower third molars.

Protostylid pits on 50 lower third molars were studied. The depth and width of the pits, the thickness of the enamel at the pit bottom and the concavity of the dentino-enamel junction under the pit were measured by light microscopy. The pit content was examined by scanning electron microscopy and X-ray spectral microanalysis. The results show that the morphometric variables of protostylid pits are similar to those of occlusal fissures and pits. The protostylid pits were seen to contain globular formations, belonging mainly to dental calculus; organic rod-shaped bodies, which could represent remnants of the enamel organ--or more probably--foreign bodies, were frequently observed. The study suggests that the development of the most common form of protostylid is basically similar to that of an occlusal cusp, with variations attributable to the low expression of the protostylid and particularities of cusp development in the lateral tooth wall.

Calcium↗