Qualitative Histopathology Research Articles

Prenatal test cohort of a modified rat comparative thyroid assay adding brain thyroid hormone measurements and histology but lowering group size appears able to detect disruption by sodium phenobarbital

The Comparative Thyroid Assay (CTA, USEPA) is a screening test for thyroid hormone (TH) disruption in peripheral blood of dams and offspring. Recently, we began investigating feasible improvements to the CTA by adding examination of offspring brain TH concentrations and brain histopathology. In addition, we hypothesize that the number of animals required could be reduced by 50 % while still maintaining sensitivity to characterize treatment related changes in THs. Previously, we showed that the prenatal test cohort of the modified CTA could detect 1000 ppm sodium phenobarbital (NaPB)-induced suppression of brain T3 (by 9 %) and T4 (by 33 %) with no significant changes in serum T3 and T4 (less than 8 %). In the current study we expanded the dose response in a prenatal test cohort. Pregnant SD rats (N = 10/group) were exposed to 0, 1000 or 1500 ppm NaPB in the diet from gestational days (GD) 6 to GD20. Serum THs concentrations in GD20 dams together with serum/brain THs concentrations and brain histopathology in the GD20 fetuses were examined. NaPB dose-dependently suppressed serum T3 (up to −26 %) and T4 (up to −44 %) in dams, with suppression of T3 in serum (up to −26 %) and brain (up to −18 %) and T4 in serum (up to −26 %) and brain (up to −29 %) of fetuses but without clear dose dependency. There were no remarkable findings that deviated significantly from controls in GD20 fetal brain by qualitative histopathology. Overall, the present study suggests that the prenatal test cohort of this modified CTA is able to detect the expected fetal TH disruptions by prenatal exposure to NaPB, while also reducing the number of animals used by 50 %, consistent with the results of our previous study. These findings add to the suggestion that lowering group sizes and adding endpoints may be a useful alternative to the original CTA design.

Comparison of acute respiratory epithelial toxicity for 4-Methylimidazole and naphthalene administered by oral gavage in B6C3F1 mice

4-Methylimidazole (4MEI) is a contaminant in food and consumer products. Pulmonary toxicity and carcinogenicity following chronic dietary exposures to 4MEI is a regulatory concern based on previous rodent studies. This study examined acute pulmonary toxicity in B6C3F1 mice from 6 h to 5 days after oral gavage with a single dose of 150 mg/kg 4MEI, a double dose delivered 6 h apart, or vehicle controls. Oral gavage of 150 mg/kg naphthalene, a prototypical Club cell toxicant, was used as a positive control. Intrapulmonary conducting airway cytotoxicity was assessed in fixed-pressure inflated lungs using qualitative histopathology scoring, quantitative morphometric measurement of vacuolated and exfoliating epithelial cells, and immunohistochemistry. 4MEI treatment did not change markers of cytotoxicity including the mass of vacuolated epithelium, the thickness of the epithelium, or the distributions of epithelial proteins: secretoglobin 1A1, proliferating cell nuclear antigen, calcitonin gene-related peptide, and myeloperoxidase. 4MEI and vehicle controls caused slight cytotoxicity with rare vacuolization of the epithelium relative to the severe bronchiolar epithelial cell toxicity found in the naphthalene exposed mice at terminal bronchioles, intrapulmonary airways, or airway bifurcations. In summary, 4MEI caused minimal airway epithelial toxicity without characteristic Club Cell toxicity when compared to naphthalene, a canonical Club Cell toxicant.

Stereology of the Peripheral Nervous System.

Qualitative histopathology has been the gold standard for evaluation of morphological tissue changes in all organ systems, including the peripheral nervous system. However, the human eye is not sensitive enough to detect small changes in quantity or size. Peripheral nervous system toxicity can manifest as subtle changes in neuron size, neuron number, axon size, number of myelinated or unmyelinated axons, or number of nerve fibers. Detection of these changes may be beyond the sensitivity of the human eye alone, necessitating quantitative approaches in some cases. Although 2-dimensional (2D) histomorphometry can provide additional information and is more sensitive than qualitative evaluation alone, the results are not always representative of the entire tissue and assumptions about the tissue can lead to bias, or inaccuracies, in the data. Design-based stereology provides 3D estimates of number, volume, surface area, or length, and stereological principles can be applied to peripheral nervous system tissues to obtain accurate and precise estimates, such as neuron number and size, axon number, and total intraepidermal nerve fiber length. This review describes practical stereological approaches to 3 compartments of the peripheral nervous system: ganglia, peripheral nerves, and intraepidermal nerve fibers.

Falcaria vulgaris Extract Attenuates Ethanol-induced Renal Damage by Reducing Oxidative Stress and Lipid Peroxidation in Rats.

Background:Alcohol consumption is capable of producing free radicals and inducing disturbance in body antioxidant. Falcaria vulgaris (F. vulgaris) is a vegetable and it has beneficial antioxidant effects.Materials and Methods:Forty-eight Wistar rats were divided randomly into eight groups (n = 6): control normal (saline) and ethanol (5g EtOH/kg body weight/24h) control groups, F. vulgaris groups (50, 100, and 150mg/kg), and F. vulgaris + ethanol treated groups (50, 100, and 150mg/kg). Treatments were administered intraperitoneally and through gavage daily for 12 weeks. Parameters related to the function and the histology of the kidneys were evaluated and statistically analyzed from kidney and blood serum samples with respect to the groups.Results:Ethanol administration increased significantly Bowman’s space, qualitative histopathology indices, kidney malondialdehyde (MDA) level, blood urea nitrogen (BUN), creatinine, and nitrite oxide levels and decreased significantly total antioxidant capacity (TAC) level and diameter and number of renal corpuscles compared to that in the control normal group (P < 0.001). The F. vulgaris and F. vulgaris + ethanol treatments in a dose-dependent manner reduced significantly Bowman’s space, qualitative histopathology indices, kidney MDA level, BUN, creatinine, and nitrite oxide levels and increased significantly TAC level and diameter and number of renal corpuscles compared to that in the ethanol normal group (P < 0.001).Conclusion:It seems that F. vulgaris administration in a dose-dependent manner improved kidney injury induced by ethanol in rats.

Bone Toolbox: Biomarkers, Imaging Tools, Biomechanics, and Histomorphometry.

Bone is a unique tissue with turnover, metabolic, and cellular activities that vary through development to aging and with a mineralized matrix in which the current state and the history of a bone coexist. Qualitative histopathology often lacks sensitivity to detect changes in bone formation, mineralization and resorption, which often requires chronic dosing to result in structural changes such as variation in bone mass and geometry. A large panel of modalities can be used to fully analyze the health of the skeleton, including biomarker evaluation in serum or urine, imaging techniques ranging from radiology to computed tomography, biomechanical testing, and undecalcified tissue processing with bone histomorphometry. The use of clinically relevant biomarkers provides an important noninvasive, sensitive, rapid, and real-time tool to monitor bone activity at the whole skeleton level when conducting safety assessments in a preclinical setting. Imaging modalities also allow in vivo longitudinal assessments with a powerful, noninvasive and clinically translatable tools to monitor drug effects. Different imaging modalities are used in the preclinical studies to evaluate the bone tissues: standard radiography, dual-energy X-ray absorptiometry, peripheral quantitative computed tomography (pQCT), micro-computed tomography, and high-resolution pQCT. Bone histomorphometry is an important tool that provides sensitive evaluation to detect effects of test articles on bone resorption, formation, mineralization, remodeling rates and growth to address a potential target- or class-related theoretical bone liability. Ultimately, the measurement of bone mechanical properties in pharmaceutical testing is critical to understand the potential effects of that pharmaceutical on bone health and fracture risk. Important considerations are required for including these different techniques in toxicology rodents and nonrodent studies, to actually integrate these into safety assessment.

Ecotoxicological impacts of exposure to copper oxide nanoparticles on the gill of the Swan mussel, Anodonta cygnea (Linnaeus, 1758)

ABSTRACTThis study was conducted to investigate the ecotoxicological effects of exposure to copper oxide nanoparticles (CuO NPs) on the gill of the swan mussel Anodonta cygnea using several approaches including qualitative and quantitative histopathology, ultra-morphology (scanning electron microscopy [SEM]) and measures of clearance rate (CR) and bioaccumulation of CuO NPs. Histological alterations in mussels exposed to 0.25 (T1), 2.5 (T2) and 25.0 µg L−1 (T3) CuO NPs for 12 days include changes in the length and form of gill lamellae, changes in inter-lamellar spaces, epithelial hyperplasia, atrophy and tissue rupture. Ultra-morphological changes following CuO NP exposure included epithelial hyperplasia and hypertrophy, epithelial lifting, tissue rupture (water channel fusion) and extensive necrosis of the gill surfaces. IGill (gill damage severity) index values for both histopathological and ultra-morphological data were significantly (P < 0.05) higher in T3. The CR of mussels was significantly (P < 0.05) lower in the highest exposure concentration (CR = 39.21 ± 16.85 [L min−1 g−1 dry weight]) in comparison to controls (CR = 108 ± 47.14 [L min−1 g−1 dry weight]). CuO NPs accumulated in exposed mussels at all exposure concentrations until day 4, but there was no further change in accumulation levels by the end of the exposure period. The accumulated content of CuO NPs was significantly (P < 0.05) lower in 25.0 µg L−1 exposure concentration. Based on these results, significant accumulation of CuO NPs in the gills of swan mussel could affect histological and ultra-structural characteristics of this organ and consequently have deleterious impacts on its filtration activity.

Resveratrol attenuates malathion-induced renal damage by declining oxidative stress in rats

Background: Malathion is the most organophosphates which are capable to produce free radicals and induce disturbance in body antioxidant. Resveratrol is an herbal polyphenol and it has been beneficial antioxidant effects during short‑term administration. This study was designed to evaluate the effects of resveratrol against damage induced by malathion to the kidneys of rats. Materials and Methods: Forty‑eight Wistar rats divided randomly into eight groups (n = 6): sham (saline) and malathion control treated groups (27 mg/kg); resveratrol groups (2, 8, and 20 mg/kg); and resveratrol + malathion‑treated groups (2, 8, and 20 mg/kg). Treatments were administered intraperitoneally and gavage daily for 45 days. Parameters related to the function and the histology of the kidneys were evaluated and statistically analyzed from kidney and blood serum samples in respect of the groups. Results: Malathion administration increased significantly Bowman’s space, qualitative histopathology indices, kidney malondialdehyde (MDA) level, blood urea nitrogen (BUN), creatinine, and nitrite oxide levels and decreased significantly total antioxidant capacity (TAC) level and diameter and number of renal corpuscles compared to the Sham group (P < 0.001). The resveratrol and resveratrol + malathion treatments in a dose‑dependent manner reduced significantly Bowman’s space, qualitative histopathology indices, kidney MDA level, BUN, creatinine, and nitrite oxide levels and increased significantly TAC level and diameter and number of renal corpuscles compared to the malathion control group (P < 0.001). Conclusion: It seems that resveratrol administration in a dose‑dependent manner improved kidney injury induced by malathion in rats.

Chicken egg fetal liver DNA and histopathologic effects of structurally diverse carcinogens and non-carcinogens

Chicken egg fetal livers were evaluated for histopathological changes produced by four genotoxic hepatocarcinogens: 2-acetylaminofluorene (AAF), aflatoxin B1 (AFB1), benzo[a]pyrene (BaP), diethylnitrosamine (DEN); four structurally related non- or weakly- carcinogenic comparators: fluorene (FLU), aflatoxin B2 (AFB2), benzo[e]pyrene (BeP), N-nitrosodiethanolamine (NDELA); two epigenetic hepatocarcinogens: clofibric acid (CFA), phenobarbital (PB); and the non-carcinogen, D-mannitol (MAN). CFA, PB and MAN were also assessed for formation of DNA adducts using the 32P nucleotide postlabeling (NPL) assay and for DNA breaks using the comet assay. CFA was also assessed in enhanced comet assay for oxidative DNA damage induction. Eggs were dosed on days 9- 11 of incubation. For genotoxicity evaluation, livers were collected 3h after the last dose. Liver qualitative histopathology assessment was performed on days 12 and 18 of incubation. CFA was negative for DNA adducts but yielded clear evidence of DNA breaks due to oxidative stress. PB and MAN produced no DNA adducts or breaks. Liver to body weight ratios were not affected in most groups, but were decreased in DEN groups, and increased after PB dosing. Livers from control groups, FLU, AFB2, BeP, NDELA, CFA, and MAN groups, displayed a typical hepatocellular trabecular pattern at both time points. In contrast, the four genotoxic carcinogens induced time- and dose- related interference with fetal liver cell processes of proliferation, migration and differentiation, leading to hepatocellular and cholangiocellular pleomorphic dysplasia and re-(de-) differentiation with distortion of the trabecular pattern. In addition, dosing with the high dose of DEN produced gallbladder agenesis. PB induced hepatocellular hypertrophy, interference with migration, expressed as distortion of the trabecular pattern, and a moderate cholangiocellular dysplasia. In summary, histopathological analysis of chicken fetal livers revealed developmental anomalies, as well as genotoxicity-induced and, in the case of PB, adaptive morphological changes. Thus, the model provides histopathological outcomes of molecular effects.

Practical Stereology Applications for the Pathologist.

Qualitative histopathology is the gold standard for routine examination of morphological tissue changes in the regulatory or academic environment. The human eye is exceptional for pattern recognition but often cannot detect small changes in quantity. In cases where detection of subtle quantitative changes is critical, more sensitive methods are required. Two-dimensional histomorphometry can provide additional quantitative information and is quite useful in many cases. However, the provided data may not be referent to the entire tissue and, as such, it makes several assumptions, which are sources of bias. In contrast, stereology is design based rather than assumption based and uses stringent sampling methods to obtain accurate and precise 3-dimensional information using geometrical and statistical principles. Recent advances in technology have made stereology more approachable and practical for the pathologist in both regulatory and academic environments. This review introduces pathologists to the basic principles of stereology and walks the reader through some real-world examples for the application of these principles in the workplace.

Characterization of the Exocrine Pancreas in the Male Zucker Diabetic Fatty Rat Model of Type 2 Diabetes Mellitus Following 3 Months of Treatment With Sitagliptin

Sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor-based incretin therapy intended for the treatment of type 2 diabetes mellitus (T2DM), has not been linked to adverse effects on the pancreas in prospective clinical trials or in nonclinical toxicology studies. To further assess potential pancreatic effects, sitagliptin was studied in the male Zucker diabetic fatty (ZDF) rat model of T2DM. Following 3 months of oral dosing with vehicle, or sitagliptin at doses 3- to 19-fold above the clinically therapeutic plasma concentration, which increased active plasma glucagon-like peptide-1 levels up to approximately 3-fold, or following 3 months of oral dosing with metformin, a non-incretin-based reference T2DM treatment, the pancreas of male ZDF rats was evaluated using qualitative and quantitative histopathology techniques. In the quantitative evaluation, proliferative index was calculated in exocrine pancreatic ducts and ductules using computer-based image analysis on sections stained by immunohistochemistry for cytokeratin (a cytoplasmic epithelial cell marker) and Ki-67 (a nuclear marker of recent cell division). Relative to controls, sitagliptin treatment did not alter disease progression based on detailed clinical signs and clinical pathology assessments. Sitagliptin treatment did not result in pancreatitis or any adverse effect on the pancreas based on a qualitative histopathology evaluation. Proliferative index did not increase with sitagliptin treatment based on quantitative assessment of more than 5000 sections of pancreas, where control group means ranged from 0.698-0.845% and sitagliptin-treated group means ranged from 0.679-0.701% (P = .874). Metformin treatment was similarly evaluated and found not to have adverse effects on pancreas.

Continuing Education Course #3

The continuing education course on Developmental Neurotoxicity Testing (DNT) was designed to communicate current practices for DNT neuropathology, describe promising innovations in quantitative analysis and noninvasive imaging, and facilitate a discussion among experienced neuropathologists and regulatory scientists regarding suitable DNT practices. Conventional DNT neuropathology endpoints are qualitative histopathology and morphometric endpoints of particularly vulnerable sites (e.g., cerebral, cerebellar, or hippocampal thickness). Novel imaging and stereology measurements hold promise for automated analysis of factors that cannot be effectively examined in routinely processed specimens (e.g., cell numbers, fiber tract integrity). The panel recommended that dedicated DNT neuropathology data sets be acquired on a minimum of 8 sections (for qualitative assessment) or 3 sections (for quantitative linear and stereological analyses) using a small battery of stains to examine neurons and myelin. Where guidelines permit discretion, immersion fixation is acceptable for younger animals (postnatal day 22 or earlier), and peripheral nerves may be embedded in paraffin. Frequent concerns regarding DNT data sets include false-negative outcomes due to processing difficulties (e.g., lack of concordance among sections from different animals) and insensitive analytical endpoints (e.g., qualitative evaluation) as well as false-positive results arising from overinterpretation or misreading by inexperienced pathologists.

Improved detection of incipient vascular changes by a biotechnological platform combining post mortem MRI in situ with neuropathology

The histopathological counterpart of white matter hyperintensities is a matter of debate. Methodological and ethical limitations have prevented this question to be elucidated. We want to introduce a protocol applying state-of-the-art methods in order to solve fundamental questions regarding the neuroimaging–neuropathological uncertainties comprising the most common white matter hyperintensities [WMHs] seen in aging. By this protocol, the correlation between signal features in in situ, post mortem MRI-derived methods, including DTI and MTR and quantitative and qualitative histopathology can be investigated. We are mainly interested in determining the precise neuroanatomical substrate of incipient WMHs. A major issue in this protocol is the exact co-registration of small lesion in a tridimensional coordinate system that compensates tissue deformations after histological processing. The protocol is based on four principles: post mortem MRI in situ performed in a short post mortem interval, minimal brain deformation during processing, thick serial histological sections and computer-assisted 3D reconstruction of the histological sections. This protocol will greatly facilitate a systematic study of the location, pathogenesis, clinical impact, prognosis and prevention of WMHs.

Dacarbazine induces genotoxic and cytotoxic germ cell damage with concomitant decrease in testosterone and increase in lactate dehydrogenase concentration in the testis

Treatment of cancers with cytotoxic agents such as alkylating drugs often, but not always results in transient to permanent testicular dysfunction. The present study was planned to investigate the effects of dacarbazine [5-(3,3-dimethyltriazeno) imidazole-4-carboxamide] on testicular function in mice. Swiss albino mice (9–12 weeks old) were treated with 0, 5, 25, 50, or 100 mg/kg body weight/day dacarbazine (i.p.) for 5 days at intervals of 24 h between treatments. Mice were sacrificed on days 7, 14, 21, 28, 35, 49, and 70 after the last treatment (6 mice/dose/sample time), and the epididymal sperm count, sperm motility, sperm morphology, testicular histopathology (qualitative histopathology, seminiferous tubular diameter and epithelial height), and intra-testicular levels of testosterone and lactate dehydrogenase were assessed. Dacarbazine decreased the body weight only on day 28 at 25 mg/kg dose-level, but increased the paired testes weights at 50 mg/kg on day 7, at 25–100 mg/kg on day 14, and at 25 and 50 mg/kg on day 21 ( P < 0.05–0.01; one-way ANOVA and Bonferroni's post hoc test). The sperm count was decreased on all sampling days except at 5 and 25 mg/kg dose-levels on day 70, but with severe oligospermia on days 28 and 35 ( P < 0.05–0.001). The sperm motility was decreased at 100 mg/kg on days 14 and 21, at 5, 25, and 100 mg/kg on day 28, and at all dose-levels on day 35 ( P < 0.05–0.001). Dacarbazine induced both head and tail abnormalities and some sperms with cytoplasmic droplets, but significant increase was seen in all dose groups on days 14 and 21, and at 100 mg/kg dose-level on day 35. Drug-induced epithelial sloughing was seen on days 14–35 and other histopathological changes observed were vacuoles and abnormal cells. The STD was increased at 25–100 mg/kg on day 7, at all dose-levels on day 14, at 50–100 mg/kg on days 21 and 28, but without any effects on days 35–70 ( P < 0.05–0.001), and the tubular lumen was found dilated. The SE was increased on days 7, 21 and 28 at 100 mg/kg and on day 14 at 50–100 mg/kg. Dacarbazine reduced the intra-testicular testosterone level at 100 mg/kg on day 7, at 5, 50 and 100 mg/kg on day 14, at all dose-levels on days 21, 28, and 35, and at 50 mg/kg on day 49 ( P < 0.05–0.001). The intra-testicular lactate dehydrogenase concentration increased at all dose-levels up to day 35, but without any effect on days 49 and 70 ( P < 0.05–0.001). There was no particular dose–response of dacarbazine on any parameters tested. The sperm count (except on day 7-positive correlation; Pearson product moment correlation) or sperm motility did not have any relation but increase in abnormal sperms showed negative correlation with decrease in testosterone level on days 7, 21 and 28. Decrease in sperm count was in negative correlation on days 14 and 35, and increase in abnormal sperms showed positive correlation on day 35 with increase in LDH level. Finally, the decrease in sperm motility had no correlation with increase in abnormal sperm shapes. We conclude that dacarbazine is genotoxic and cytotoxic to the mouse testis in a transient fashion, and these effects are exerted along with decrease in testosterone and increase in lactate dehydrogenase levels in the testis.

Effects of the Fungicide Mancozeb on Liver Structure of Nile Tilapia, Oreochromis niloticus: Assessment and Quantification of Induced Cytological Changes Using Qualitative Histopathology and the Stereological Point-Sampled Intercept Method

1 UTAD–University of Tras-os-Montes and Alto Douro, Apartado 1013, 5000-911 Vila Real, Portugal 2 CETAV–Center of Technological, Environmenal, and Life Studies, Apartado 1013, 5000-911 Vila Real, Portugal 3 ICBAS–Institute of Biomedical Sciences Abel Salazar, Largo Professor Abel Salazar, 2, 4099-003 Porto, Portugal 4 CIIMAR–Interdisciplinary Center for Marine and Environmental Research, Rua dos Bragas, 289, 4050-123, Porto, Portugal

ADHESION FORMATION AFTER FLEXOR TENDON REPAIR: COMPARISON OF TWO- AND FOUR-STRAND REPAIR WITHOUT EPITENDINOUS SUTURE

Increased handling, increased bulk at the repair site and an increase in external suture material may affect adhesion formation and gliding after tendon repair. A previous study(1) showed no significant difference in biomechanical or histopathological measurement of adhesion formation in two- and four-strand repairs combined with an epitendinous suture in the chicken model. In the present study, the flexor digitorum profundus tendon of the middle toe of 47 broiler chickens was cut and repaired with either a single (two-strand) or double (four-strand) modified Kessler core suture without epitendinous suture and immobilised for four weeks. Adhesion formation was measured by biomechanical testing or quantitative and qualitative histopathology. Biomechanical and histological data showed no differences between two- and four-strand repairs. Results did not differ from the previous study which used an epitendinous suture. Adhesion formation is not necessarily increased when multi-strand techniques are used, nor by the placement of an epitendinous suture if care is taken with surgical technique. Individual healing response introduces more variability than an increase in tendon handling by an experienced surgeon.

Skeletal efficacy with parathyroid hormone in rats was not entirely beneficial with long-term treatment.

We report the consequences of prolonged treatment with recombinant human parathyroid hormone (1-34) (PTH) in male and ovariectomized female rats with mature skeletons. Intact male and osteopenic, ovariectomized, female F-344 rats were evaluated after 1 year of treatment with 0, 8, or 40 microg/kg/day s.c. PTH. Males and females were about 6 months of age at study initiation; females were ovariectomized (Ovx) for 5 weeks before initiation of PTH treatment. PTH did not affect the survival of either intact males or ovariectomized females. Qualitative histopathology showed expected changes associated with aging in kidneys and proximal tibiae, with no treatment-related anomalies after 1 year of PTH administration. PTH slightly increased the femoral length of ovariectomized females but not that of males. No significant differences in femoral length were observed between sham and Ovx controls. Proximal femora of the males and ovariectomized females given the high dose of 40 microg/kg showed 211 and 186% greater trabecular bone area, 118 and 94% greater cortical thickness, 170 and 189% greater trabecular number, and 321 and 404% greater connectivity (node-to-node struts) compared with respective vehicle controls. Increased trabecular and endocortical surface apposition coincided with a 78 and 70% loss of marrow space for males and females treated with PTH, respectively. Biomechanical strength (ultimate load) of the femoral neck increased by 73 and 76%, respectively, in males and ovariectomized females. Cortical bone analyses of the femoral midshaft showed 105 and 72% increases in bone mineral content, 67 and 55% increases in bone mineral density, and 22 and 10% increases in cross-sectional area for males and ovariectomized females, respectively, with altered shape of femora. Biomechanical analyses of the midshaft showed substantial increases in strength and stiffness but a reduction in ultimate strain, which was likely due to the altered geometry of the midshaft for PTH groups. Aging effects on strength of vertebra and femoral midshaft were reversed by PTH treatment. In summary, the 1-year treatment duration, which represents about 50% of lifetime, did not affect survival and was not associated with any treatment-related anomalies in the kidney or skeleton. PTH reversed the aging process in bones but not kidneys and substantially increased bone mass and strength to well beyond normally attained levels. However, compared with short-term studies reported previously, there seemed to be no advantages to extending PTH treatment to 12 months in rat bones.

Effect of Penicillin on Experimental Acute Otitis Media: A histopathological study of goblet cell density, bone modelling dynamics, polyp and adhesion formation

Clinical studies have shown that the effect of antibiotic treatment on acute otitis media is modest. Experimental acute otitis media induces a number of histopathological changes in the middle ear mucosa. Among these are increased goblet cell density, polyp and adhesion formation, as well as massive osteoneogenesis. To investigate the effect of penicillin administration on these histopathological features, we employed a rat model of acute pneumococcal otitis media. Five of 25 rats were sacrificed on days 4, 8, 16, 90 and 180 post-inoculation, preceded by oral administration of penicillin V 100 mg/kg/day, initiated on day 2 and lasting 5 days. Using a light microscope, qualitative and quantitative histopathology of middle ear goblet cell density, bone-modelling dynamics, polyp and adhesion formation was registered and compared with previous studies of untreated animals. Increase in goblet cell density and new bone formation was reduced significantly by treatment, whereas polyp and adhesion formation was unaffected by penicillin administration. It is concluded that penicillin reduces middle ear secretory capacity and new bone formation during and following acute otitis media, conceivably preventing subsequent development of secretory otitis media, leaving polyp and adhesion formation unchanged.

Histopathology of the flexor tendon sheaths and its relevance in idiopathic carpal tunnel syndrome

Compression of the median nerve in the carpal tunnel can be produced by a variety of factors, including fractures, metabolic disturbances, rheumatoid arthritis or anatomical anomalies. When it is not possible to identify a specific cause, the term ”idiopathic carpal tunnel syndrome” is used. Although this disease is very common, its pathophysiology is still unclear. In the past, the presence of a chronic non-specific tenosynovitis around the flexor tendons was postulated but several investigations failed to show any inflammatory reaction in the carpal synovium. In this study, the histology of the flexor tendon sheaths in a group of 50 patients surgically treated for idiopathic carpal tunnel syndrome (ICTS) have been investigated both from the qualitative (histopathology) and quantitative (micrometric evaluation) points of view. Lack of acute or chronic inflammatory cells, connective disorganization, and vascular modifications are the main histological findings which are present in all the specimens, regardless of the patient’s age, the duration of the sensory symptomatology or the severity of the neurological lesion on EMG exam. The carpal synovium in these patients appeared thickened when compared to the specimens obtained from the control group. However, on micrometric evaluation a relationship between synovial thickness and severity of the symptomatology or of the EMG data was not observed. The carpal synovium in ICTS has a consistent histological appearance and is increased in thickness when compared with normal specimens.

Experimental Intracerebral Hemorrhage: Early Removal of a Spontaneous Mass Lesion Improves Late Outcome

The purpose of the present study was to determine whether early removal of an experimental intracerebral mass altered cerebral blood flow, brain water content, neuropathological findings, or neurological function 24 hours later. In three experimental series, a 50-microliter balloon was inflated within the right caudate nucleus in rats. At 24 hours after inflation, we studied cerebral blood flow by quantitative autoradiography, brain specific gravity, and qualitative histopathology by light microscopy. The animals were also assessed using a simple neurological deficit scale. In each series, half of the animals had the balloon inflated for 10 minutes (Group 1), and half had the balloon inflated permanently (Group 2). After transient inflation, there were surprisingly small differences in the blood flow between the two cerebral hemispheres at 24 hours. By contrast, in animals with permanent inflation, several indices of blood flow were significantly worse in the hemisphere ipsilateral to the balloon: the mean and median blood flow levels in the caudate nucleus; the mean blood flow in the cerebral cortex; and the area of cortex with ischemic levels of blood flow. The specific gravity was reduced in areas surrounding the site of balloon insertion after either transient or permanent inflation, and there was evidence of ischemic cell damage in all animals studied. These changes were more severe after permanent inflation, but the differences were not significant. Neurological outcome was significantly better after transient as compared with permanent inflation. The present findings contradict previous results and suggest that early removal of an intracerebral mass may have subsequent benefits.

Acute effects and long-term sequelae of 1,3-dinitrobenzene on male reproduction in the rat. II. Quantitative and qualitative histopathology of the testis.

This study determined the quantitative and qualitative histopathologic effects of a single oral dose of 1,3-dinitrobenzene (48 mg/kg) on the rat testis from 1 to 175 days postexposure. The testis was damaged severely by hour 24, as evidenced by increased numbers of regressive seminiferous tubules that exhibited degenerating pachytene spermatocytes, chromatin margination in spermatids, giant cells, deformed spermatid heads, retained spermatids, and reduced numbers of meiotic figures. The major effects during the first 48 hours posttreatment were degeneration or exfoliation of pachytene spermatocytes and round spermatids and the retention of step 19 spermatids. These regressive effects continued until 24 days, after which the tubules either recovered or became atrophic. At the end of the study (175 days), three males were normal, one had regressed testicles, and three males had atrophic tubules (15 to 45%). Several cellular abnormalities were common throughout the period. In addition, the frequency of the stages of spermatogenesis was altered, an indication of a disturbance in the kinetics of spermatogenesis. 1,3-Dinitrobenzene produced profound and specific lesions in the seminiferous tubules, and recovery was slow and incomplete. Atrophic tubules seemed to form if the normal cellular associations were not reestablished within 24 days, possibly due to the inability of Sertoli cells to reorganize the synchrony of germ cell development.