Integrity of lysosomes in the isolated perfused rat liver before and after exposure to dimethylsulphoxide.

We have studied the integrity of lysosomes in isolated rat livers perfused for 3, 4, or 6 hr at 35 °C with BSA (40 g/l) in Krebs Ringer bicarbonate buffer. The latency and sedimentability of β-glucuronidase in homogenates of these livers was well maintained even after 6 hr. The latency and sedimentability of acid phosphatase remained at about control levels during the first 4 hr of perfusion but decreased between 4 and 6 hr. These decreases in latency and sedimentability correlated with a decrease in bile production and an increase in the rate of release of GOT into the perfusate and could indicate either intracellular disruption of lysosomes

Latencies, Sedimentabilities, and Specific Activities of Acid Phosphatase and β-Glucuronidase in Homogenates of Rat Liver Prepared before or at Various Times after Exposure to 1.4 m Me₂SO for 1 hr

     

2.

Hemopoietic activities of cryopreserved murine fresh and postmortem bone marrow cells     

P. I. Liu  K. C. Poon  L. Crook  S. S. Liu  C. C. Hong 《Cryobiology》1979,16(6):513-516

The percentage of preservation of erythropoietic and granulopoietic precursor cells in the murine bone marrow was studied using in vitro methylcellulose clonal cell culture assays and in vivo murine spleen colony assays. This study clearly demonstrates

a. Type of Spleen Colonies Induced by 6-hr Postmortem Murine Bone Marrow Cells^a

Time (hr)	0	3	4	6
Acid phosphatase
Latency (%)	83.2 ± 0.8	64.7 ± 5.1	62.4 ± 7.9	68.9 ± 5.4
Sedimentability (%)	81.7 ± 0.6	77.6 ± 3.1	81.0 ± 3.4	79.4 ± 5.1
Specific activity (mIU/mg protein)	2.8 ± 0.4	2.8 ± 0.2	2.4 ± 0.4	1.6 ± 0.2
β-Glucuronidase
Latency (%)	06.8 ± 1.5	71.3 ± 4.3	74.2 ± 2.5	63.3 ± 4.5
Sedimentability (%)	69.5 ± 0.3	75.4 ± 3.2	75.0 ± 1.1	74.6 ± 2.0
Specific activity (mIU/mg protein)	1.8 ± 0.1	1.6 ± 0.1	1.6 ± 0.2	1.6 ± 0.2

	Mean (%)
Type of colonies	t Score	P Value	Unfrozen	Frozen
			Erythrocytic	26.283	14.100	2.09	0.059
Granulocytic	23.741	32.917	1.45	0.173
Mixed	49.321	52.700	0.55	0.59

a

$\text{N = 92}$. the presence of pluripotent hemopoietic precursor cells in cryopreserved 0-, 3-, 6-, 9-, and 12-hr postmortem murine bone marrow cells. Apparently, the erythropoietic precursor cells are more sensitive to freezing injury as compared to granulopoietic precursor cells.

     

Hemopoietic activities of cryopreserved murine fresh and postmortem bone marrow cells

The percentage of preservation of erythropoietic and granulopoietic precursor cells in the murine bone marrow was studied using in vitro methylcellulose clonal cell culture assays and in vivo murine spleen colony assays. This study clearly demonstrates

a. Type of Spleen Colonies Induced by 6-hr Postmortem Murine Bone Marrow Cells^a

A digital thermocouple thermometer

Measurements of the reproducibility of a random selection of copper/constantan thermocouples were made and it was found that they agreed within 1 ° C. Based on this finding, a digital thermocouple thermometer was designed and constructed incorporating a thermocouple linearizer and cold junction compensation. The instrument

Accuracy of the Completed Digital Thermometer

     

4.

Hyperosmotic injury in mammalian cells. Volume and alkali cation alterations of CHO cells in unprotected and DMSO-treated cultures.     

S Mironescu 《Cryobiology》1978,15(2):178-191

Correlated studies on volume distributions and cation (Na⁺ and K⁺) content of CHO cells in suspension were carried out after various exposures to hypertonic NaCl or sucrose (500–7550 mOsm in both the presence and absence of DMSO (5–20%; $\text{w}\text{v}$). The effects superimposed by ouabain (10^?2–10^?4m), amphotericin B (6–18 μg/ml), and glutaraldehyde (1.25%) on the above-mentioned parameters were also investigated. Volumetric analysis of CHO cells with the Coulter Channelyzer indicated a biphasic dose-dependent response to hypertonic media, the duration of the

TABLE 2. Correlation between Volume, Survival, and Cation Content of CHO Cells Exposed to Hypertonic Media in Suspension

Temperature	Indicated	Error
(°C)	temperature	(°C)
	(°C)
?1.95.75	?195	0.75
?77.02	?78	0.38
0	0	0
52.49	53	0.51
Mean		0.413

     

5.

Cell Biology: Paper alert     

《Current opinion in cell biology》2000,12(5):525-535

A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in cell biology.

Osmolality mOsm	Exposure (min)								Hypertonic agent
					NaCl				Sucrose
		$\text{V}{}^{\mathrm{a}}$	Na+	K+	$\text{S}{}^{\mathrm{b}}$	V	Na+	K+	S
1000	60 or less	Small	High	High	High	Normal	Low	High	High
1500–2000	60 or less	Small	High	Low	Low	Normal	Low	High	High
2000 or over	60 or more	Small or largec	High	Very low	Very low	Small	Very low	Very low	Very low

     

6.

Reproductive potential and endocrinological responses of sheep kept under controlled lighting. I. Comparative reproductive performance of four breed types of ewe     

G. Evans  T.J. Robinson 《Animal reproduction science》1980,3(1):23-37

Five ewes of each of four breed types were kept in each of two environmentally-controlled rooms over a period of 2.5 years. The daylength varied between 20 and 9 h on a 6-monthly cycle, including a period of 22 weeks during which daylength was decreased by 0.5 h per week, 2 weeks in which it increased from 9 to 20 h, and 2 weeks at 20 h; each room operated 3 months out of phase with the other. Towards the end of the period of decreasing daylength each ewe was synchronised with a progestagen sponge for 12 days, given an injection (i.m.) of 750 I.U. pregnant mares' serum gonadotrophin (PMSG) on withdrawal, and inseminated 48 and 58 h later (500 million fresh undiluted sperm per insemination). Thus, insemination occurred at a single synchronised oestrus every 6 months. Progesterone pregnancy diagnosis was performed on blood samples taken 18 days later and parturition was induced by an injection (i.m.) of 16 mg dexamethasone on day 143 of gestation. Lambs were weaned at birth, allowing the ewes approximately 5.5 weeks to recover before the next insemination and a ‘successive’ conception.The performance of the four types of ewe, starting as maidens, is tabulated.

Contents (chosen by)
525	Cytoskeleton (Desai and Holleran)
526	Cell regulation (Roche, Servant and Weiner)
528	Nucleus and gene expression (Aasland and Weinzierl)
529	Membranes and sorting (Ponnambalam)
530	Membrane permeability (Slesinger)
531	Cell-to-cell contact and extracellular matrix (Pfaff)
533	Cell differentiation (van Roessel, Kaltschmidt, Tsang and Huckriede)
534	Cell multiplication (Sclafani)

     

7.

DNA synthesis catalysed by endogenous templates and DNA-dependent DNA polymerases in spermatogenic cells from rat     

Norman B. Hecht  Martti Parvinen 《Experimental cell research》1981,135(1):103-114

The activity levels of DNA polymerases α and β have been measured by autoradiography in squash preparations from rat testis of sexually mature animals. Similar results were obtained with ‘fixed’ samples (dipped in acetone: ethanol for 5 min at 25 °C) or ‘unfixed’ samples (frozen in liquid nitrogen and freeze-dried). The activities of DNA polymerases α and β in situ were distinguished by differential assay conditions and by selective inhibition with compounds such as N-ethylmaleimide and aphidicolin. Using the endogenous chromatin as template, maximal activity for both enzymes was obtained in the presence of all four deoxyribonucleoside triphosphates, MgCl₂ and ethylene glycol. When DNA polymerase activities in several predominant testicular cell types (pre-leptotene primary spermatocytes, pachytene primary spermatocytes, round spermatids and elongated spermatids) were quantitatively compared, on a per cell basis, the following percentage distribution was observed:

Conceptions	Merino	Dorset Horn × Merino	Border Leic. × Merino	South Suffolk × Merino	$\text{P}$
Successive (%)	20.0	12.5	11.1	47.6	$\text{< 0.01}$
Non-successive (%)	76.0	76.9	66.7	95.0	$\text{< 0.05}$
Overall (%)	51.1	52.4	44.4	70.7	$\text{< 0.05}$
Mean litter size	1.7	1.5	1.5	2.2	$\text{< 0.05}$
Mean lambs per ewe per year	1.8	1.6	1.3	3.1	$\text{< 0.01}$

     

8.

Clinical challenges     

《Clinical eye and vision care》1997,9(3):165-167

Glaucomatocyclitic crisis should be considered in the differential diagnosis of unilaterally increased IOP. A careful history, slit-lamp examination and gonioscopic examination will assist the examiner in making an accurate diagnosis.The etiology of this syndrome remains unknown. If indeed it is a disturbance of the anterior intraocular vasculature secondary to an autonomic abnormality, any of the proposed etiologies might possibly trigger an attack (Table 2).Treatment at this time should consist of 1 gH. 0.5% apraclonidine given in office or a topical steroid, cycloplegic, and ocular hypotensive agent combination. Follow-up should be within 24 h to monitor for IOP reduction. If treatment with apraclonidine is initiated, additional drops should be instilled as needed to lower the IOP to acceptable levels. Prophylactic treatment with topical steroids has been considered in this mostly benign syndrome [14]. However, the potential side-effects of long-term steroid use and the unpredictable frequency of glaucomatocyclitic crises may preclude steroid use in these cases. Table 2. Proposed etiological factors and diseases related to glaucomatocyclitis crisis.

	Pre-leptotene primary spermatocyte %	Pachytene primary spermatocyte %	Round spermatid %	Elongated spermatid %
DNA polymerase α	25	42	30	3
DNA polymerase β	29	34	36	1

     

9.

Heat exchange in the cryosurgery of Menière's disease: Experimental and clinical studies     

S. Harly  J.E. Aastrup  O. Elbrønd 《Cryobiology》1977,14(5):609-613

The temperature course in the lateral semicircular canal and in the facial canal was studied in experiments during freezing of the semicircular canal. The course of the temperature was measured with thermocouples. Concurrently, the heat flow was measured, and also the total heat exchange was measured throughout the freezing period by a thermoelectric heat flowmeter incorporated in the cryotip. The measurements showed correlation between the total amount of heat exchanged, the freezing time, and the temperature in the semicircular canal. This correlation was utilized to assess and calculate (the temperature of the lateral semicircular canal) the course of the cryoprocess in vivo, where it is possible to measure the heat flow and the total heat exchange during the freezing period only.

2. Results upon Vertigo

Form of developmental glaucoma

Autonomic imbalance

Allergy, peptic ulcer, stress

Herpes simplex virus

Cytomegalovirus

Varicella-zoster virus

Mesodermal dysgenesis

     

10.

A simple system for extending refrigerated, nonfrozen preservation of biological material using pressure.     

S E Charm  H E Longmaid  J Carver 《Cryobiology》1977,14(5):625-636

High pressure (above 238 atmg) substantially extends the refrigerated storage of highly perishable biological material in a nonfrozen state.

5. Calculated Equivalent Values of Pressure and Temperature for Reducing Reaction Rates of Horseradish Peroxidase

	No Vertigo	Improved	Unchanged
Number of patients	7	5	3

Pressure (atmg)	Temperature (°K)	$\text{T}\text{T}{}_0$a
0	296	0.999
272	289	0.975
340	287	0.969
408	285	0.963

a

$\text{T}{}_0\text{= 296 °}\text{K}$It has been known for some time that high pressure stops microbial growth. The effect of high pressure is to reduce further the enzyme activity at refrigerated temperatures. Two enzymes studied, peroxidase and crude trypsin from red crab intestine, demonstrated this effect.A number of food materials such as fish, beef, and chicken were tested for microbial growth and organoleptic qualities after high-pressure storage in a simple 14-liter pressure chamber. Pressure was generated by a hand pump. The results indicated that after 30 days those items held in a non-frozen state at ?3 °C and 238 atmg were not significantly different microbiologically and organoleptically from frozen controls at atmospheric pressure and ?20 °C.This system should be useful for the preservation of biological materials where freezing or thawing effects are undesirable or unknown.The energy saved compared to freezing should also be considered. Only 62% of the energy is required for storage at ?3 °C as compared with frozen storage at ?20 °C, and about 28 cal/g must be removed in cooling to ?3 °C as compared with 120 cal/g in cooling to ?20 °C.

     

Hyperosmotic injury in mammalian cells. Volume and alkali cation alterations of CHO cells in unprotected and DMSO-treated cultures.

Correlated studies on volume distributions and cation (Na⁺ and K⁺) content of CHO cells in suspension were carried out after various exposures to hypertonic NaCl or sucrose (500–7550 mOsm in both the presence and absence of DMSO (5–20%; $\text{w}\text{v}$). The effects superimposed by ouabain (10^?2–10^?4m), amphotericin B (6–18 μg/ml), and glutaraldehyde (1.25%) on the above-mentioned parameters were also investigated. Volumetric analysis of CHO cells with the Coulter Channelyzer indicated a biphasic dose-dependent response to hypertonic media, the duration of the

TABLE 2. Correlation between Volume, Survival, and Cation Content of CHO Cells Exposed to Hypertonic Media in Suspension

Cell Biology: Paper alert

A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in cell biology.

Reproductive potential and endocrinological responses of sheep kept under controlled lighting. I. Comparative reproductive performance of four breed types of ewe

Five ewes of each of four breed types were kept in each of two environmentally-controlled rooms over a period of 2.5 years. The daylength varied between 20 and 9 h on a 6-monthly cycle, including a period of 22 weeks during which daylength was decreased by 0.5 h per week, 2 weeks in which it increased from 9 to 20 h, and 2 weeks at 20 h; each room operated 3 months out of phase with the other. Towards the end of the period of decreasing daylength each ewe was synchronised with a progestagen sponge for 12 days, given an injection (i.m.) of 750 I.U. pregnant mares' serum gonadotrophin (PMSG) on withdrawal, and inseminated 48 and 58 h later (500 million fresh undiluted sperm per insemination). Thus, insemination occurred at a single synchronised oestrus every 6 months. Progesterone pregnancy diagnosis was performed on blood samples taken 18 days later and parturition was induced by an injection (i.m.) of 16 mg dexamethasone on day 143 of gestation. Lambs were weaned at birth, allowing the ewes approximately 5.5 weeks to recover before the next insemination and a ‘successive’ conception.The performance of the four types of ewe, starting as maidens, is tabulated.

DNA synthesis catalysed by endogenous templates and DNA-dependent DNA polymerases in spermatogenic cells from rat

The activity levels of DNA polymerases α and β have been measured by autoradiography in squash preparations from rat testis of sexually mature animals. Similar results were obtained with ‘fixed’ samples (dipped in acetone: ethanol for 5 min at 25 °C) or ‘unfixed’ samples (frozen in liquid nitrogen and freeze-dried). The activities of DNA polymerases α and β in situ were distinguished by differential assay conditions and by selective inhibition with compounds such as N-ethylmaleimide and aphidicolin. Using the endogenous chromatin as template, maximal activity for both enzymes was obtained in the presence of all four deoxyribonucleoside triphosphates, MgCl₂ and ethylene glycol. When DNA polymerase activities in several predominant testicular cell types (pre-leptotene primary spermatocytes, pachytene primary spermatocytes, round spermatids and elongated spermatids) were quantitatively compared, on a per cell basis, the following percentage distribution was observed:

Clinical challenges

Glaucomatocyclitic crisis should be considered in the differential diagnosis of unilaterally increased IOP. A careful history, slit-lamp examination and gonioscopic examination will assist the examiner in making an accurate diagnosis.The etiology of this syndrome remains unknown. If indeed it is a disturbance of the anterior intraocular vasculature secondary to an autonomic abnormality, any of the proposed etiologies might possibly trigger an attack (Table 2).Treatment at this time should consist of 1 gH. 0.5% apraclonidine given in office or a topical steroid, cycloplegic, and ocular hypotensive agent combination. Follow-up should be within 24 h to monitor for IOP reduction. If treatment with apraclonidine is initiated, additional drops should be instilled as needed to lower the IOP to acceptable levels. Prophylactic treatment with topical steroids has been considered in this mostly benign syndrome [14]. However, the potential side-effects of long-term steroid use and the unpredictable frequency of glaucomatocyclitic crises may preclude steroid use in these cases. Table 2. Proposed etiological factors and diseases related to glaucomatocyclitis crisis.

Heat exchange in the cryosurgery of Menière's disease: Experimental and clinical studies

The temperature course in the lateral semicircular canal and in the facial canal was studied in experiments during freezing of the semicircular canal. The course of the temperature was measured with thermocouples. Concurrently, the heat flow was measured, and also the total heat exchange was measured throughout the freezing period by a thermoelectric heat flowmeter incorporated in the cryotip. The measurements showed correlation between the total amount of heat exchanged, the freezing time, and the temperature in the semicircular canal. This correlation was utilized to assess and calculate (the temperature of the lateral semicircular canal) the course of the cryoprocess in vivo, where it is possible to measure the heat flow and the total heat exchange during the freezing period only.

2. Results upon Vertigo

A simple system for extending refrigerated, nonfrozen preservation of biological material using pressure.

High pressure (above 238 atmg) substantially extends the refrigerated storage of highly perishable biological material in a nonfrozen state.

5. Calculated Equivalent Values of Pressure and Temperature for Reducing Reaction Rates of Horseradish Peroxidase

ALGAL RESPONSE TO NUTRIENT ENRICHMENT IN FORESTED OLIGOTROPHIC STREAM1

Nutrient input in streams alters the density and species composition of attached algal communities in open systems. However, in forested streams, the light reaching the streambed (rather than the local nutrient levels) may limit the growth of these communities. A nutrient‐enrichment experiment in a forested oligotrophic stream was performed to test the hypothesis that nutrient addition has only minor effects on the community composition of attached algae and cyanobacteria under light limitation. Moderate nutrient addition consisted of increasing basal phosphorus (P) concentrations 3‐fold and basal nitrogen (N) concentrations 2‐fold. Two upstream control reaches were compared to a downstream reach before and after nutrient addition. Nutrients were added continuously to the downstream reach for 1 year. Algal biofilms growing on ceramic tiles were sampled and identified for more than a year before nutrient addition to 12 months after. Diatoms were the most abundant taxonomic group in the three stream reaches. Nutrient enrichment caused significant variations in the composition of the diatom community. While some taxa showed significant decreases (e.g., Achnanthes minutissima, Gomphonema angustum), increases for other taxa (such as Rhoicosphenia abbreviata and Amphora ovalis) were detected in the enriched reach (for taxonomic authors, see Table 2 ). Epiphytic and adnate taxa of large size were enhanced, particularly during periods of favorable growth conditions (spring). Nutrients also caused a change in the algal chl a, which increased from 0.5–5.8 to 2.1–10.7 μg chl · cm^?2. Our results indicate that in oligotrophic forested streams, long‐term nutrient addition has significant effects on the algal biomass and community composition, which are detectable despite the low light availability caused by the tree canopy. Low light availability moderates but does not detain the long‐term tendency toward a nutrient‐tolerant community. Furthermore, the effects of nutrient addition on the algal community occur in spite of seasonal variations in light, water flow, and water chemical characteristics, which may confound the observations.

Table 2. Percent abundances of the most frequent taxa in three reaches of the Fuirosos stream. U1 and U2 untreated; E, enriched both in the periods before (bef) and after (aft) the enrichment of the E reach. Acronyms identifying the taxa are indicated.

SEAWEED EXTRACTS AS A POTENTIAL TOOL FOR THE ATTENUATION OF OXIDATIVE DAMAGE IN OBESITY‐RELATED PATHOLOGIES1

Recent studies suggest that seaweed extracts are a significant source of bioactive compounds comparable to the dietary phytochemicals such as onion and tea extracts. The exploration of natural antioxidants that attenuate oxidative damage is important for developing strategies to treat obesity‐related pathologies. The objective of this study was to screen the effects of seaweed extracts of 49 species on adipocyte differentiation and reactive oxygen species (ROS) production during the adipogenesis in 3T3‐L1 adipocytes, and to investigate their total phenol contents and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activities. Our results show that high total phenol contents were observed in the extracts of Ecklonia cava (see Table 1 for taxonomic authors) (681.1 ± 16.0 μg gallic acid equivalents [GAE] · g^?1), Dictyopteris undulata (641.3 ± 70.7 μg GAE · g^?1), and Laurencia intermedia (560.9 ± 48.1 μg GAE · g^?1). In addition, DPPH radical scavenging activities were markedly higher in Sargassum macrocarpum (60.2%), Polysiphonia morrowii (55.0%), and Ishige okamurae (52.9%) than those of other seaweed extracts (P < 0.05). Moreover, treatment with several seaweed extracts including D. undulata, Sargassum micracanthum, Chondrus ocellatus, Gelidium amansii, Gracilaria verrucosa, and Grateloupia lanceolata significantly inhibited adipocyte differentiation and ROS production during differentiation of 3T3‐L1 preadipocytes. Furthermore, the production of ROS was positively correlated with lipid accumulation (R² = 0.8149). According to these preliminary results, some of the seaweed extracts can inhibit ROS generation, which may protect against oxidative stress that is linked to obesity. Further studies are required to determine the molecular mechanism between the verified seaweeds and ROS, and the resulting effects on obesity.

Table 1. List of Korean seaweed extracts of 49 species evaluated in this experiment.

A conifer genome spruces up plant phylogenomics

The Norway spruce genome provides key insights into the evolution of plant genomes, leading to testable new hypotheses about conifer, gymnosperm, and vascular plant evolution.In the past year a burst of plant genome sequences have been published, providing enhanced phylogenetic coverage of green plants (Figure ​(Figure1)1) and inclusion of new agricultural, ecological, and evolutionary models. Collectively, these sequences are revealing some extraordinary structural and evolutionary attributes in plant genomes. Perhaps most surprising is the exceptionally high frequency of whole-genome duplication (WGD): nearly every genome that has been analyzed has borne the signature of one or more WGDs, with particularly notable events having occurred in the common ancestors of seed plants, of angiosperms, and of core eudicots (the latter ''WGD'' represents two WGDs in close succession) [1,2]. Given this tendency for plant genomes to duplicate and then return to an essentially diploid genetic system (an example is the cotton genomes, which have accumulated the effects of perhaps 15 WGDs [3]), the conservation of genomes in terms of gene number, chromosomal organization, and gene content is astonishing. From the publication of the first plant genome, Arabidopsis thaliana [4], the number of inferred genes has been between 25,000 and 30,000, with many gene families shared across all land plants, although the number of members and patterns of expansion and contraction vary. Furthermore, conserved synteny has been detected across the genomes of diverse angiosperms, despite WGDs, diploidization, and millions of years of evolution.Open in a separate windowFigure 1Simplified phylogeny of land plants, showing major clades and their component lineages. Asterisks indicate species (or lineage) for which whole-genome sequence (or sequences) is (are) available. Increases and decreases in genome size are shown by arrows.Despite the proliferation of genome sequences available for angiosperms, genome-level data for both ferns (and their relatives, collectively termed monilophytes; Figure ​Figure1)1) and gymnosperms have been conspicuously lacking - until recently, with the publication of the genome sequence of the gymnosperm Norway spruce (Picea abies) [5]. The large genome sizes for both monilophytes and gymnosperms have discouraged attempts at genome sequencing and assembly, whereas the smaller genome size of angiosperms has resulted in more genome sequences being available (Table ​(Table1)1) [6]. Because of this limited phylogenetic sample, our understanding of the timing and phylogenetic positions of WGDs, the core number of plant genes, possible conserved syntenic regions, and patterns of expansion and contraction of gene families across both tracheophytes (vascular plants) and across all land plants is imperfect. This sampling problem is particularly acute in analyses of the genes and genomes of seed plants; many hundreds of genes are present in angiosperms that are not present in mosses or lycophytes, but whether these genes arose in the common ancestor of seed plants or of angiosperms cannot be determined without a gymnosperm genome sequence. The Norway spruce genome therefore offers tremendous power, not only for understanding the structure and evolution of conifer genomes, but also as a reference for interpreting gene and genome evolution in angiosperms.

Table 1

Genome sizes in land plants

Mouse Models of Osteoarthritis: A Summary of Models and Outcomes Assessment

Osteoarthritis (OA) is a multidimensional health problem and a common chronic disease. It has a substantial impact on patient quality of life and is a common cause of pain and mobility issues in older adults. The functional limitations, lack of curative treatments, and cost to society all demonstrate the need for translational and clinical research. The use of OA models in mice is important for achieving a better understanding of the disease. Models with clinical relevance are needed to achieve 2 main goals: to assess the impact of the OA disease (pain and function) and to study the efficacy of potential treatments. However, few OA models include practical strategies for functional assessment of the mice. OA signs in mice incorporate complex interrelations between pain and dysfunction. The current review provides a comprehensive compilation of mouse models of OA and animal evaluations that include static and dynamic clinical assessment of the mice, merging evaluation of pain and function by using automatic and noninvasive techniques. These new techniques allow simultaneous recording of spontaneous activity from thousands of home cages and also monitor environment conditions. Technologies such as videography and computational approaches can also be used to improve pain assessment in rodents but these new tools must first be validated experimentally. An example of a new tool is the digital ventilated cage, which is an automated home-cage monitor that records spontaneous activity in the cages.

Osteoarthritis (OA) is a multidimensional health problem and a common chronic disease.³⁶ Functional limitations, the absence of curative treatments, and the considerable cost to society result in a substantial impact on quality of life.⁷⁶ Historically, OA has been described as whole joint and whole peri-articular diseases and as a systemic comorbidity.^9,111 OA consists of a disruption of articular joint cartilage homeostasis leading to a catabolic pathway characterized by chondrocyte degeneration and destruction of the extracellular matrix (ECM). Low-grade chronic systemic inflammation is also actively involved in the process.^42,92 In clinical practice, mechanical pain, often accompanied by a functional decline, is the main reason for consultations. Recommendations to patients provide guidance for OA management.^{22, 33,49,86} Evidence-based consensus has led to a variety of pharmacologic and nonpharmacologic modalities that are intended to guide health care providers in managing symptomatic patients. Animal-based research is of tremendous importance for the study of early diagnosis and treatment, which are crucial to prevent the disease progression and provide better care to patients.The purpose of animal-based OA research is 2-fold: to assess the impact of the OA disease (pain and function) and to study the efficacy of a potential treatment.^18,67 OA model species include large animals such as the horse, goat, sheep, and dog, whose size and anatomy are expected to better reflect human joint conditions. However, small animals such as guinea pig, rabbit, mouse, and rat represent 77% of the species used.^1,87 In recent years, mice have become the most commonly used model for studying OA. Mice have several advantageous characteristics: a short development and life span, easy and low-cost breeding and maintenance, easy handling, small joints that allow histologic analysis of the whole joint,³² and the availability of genetically modified lines.¹⁰⁸ Standardized housing, genetically defined strains and SPF animals reduce the genetic and interindividual acquired variability. Mice are considered the best vertebrate model in terms of monitoring and controlling environmental conditions.^7,14,15,87 Mouse skeletal maturation is reached at 10 wk, which theoretically constitutes the minimal age at which mice should be entered into an OA study.^64,87,102 However, many studies violate this limit by testing mice at 8 wk of age.Available models for OA include the following (32,111 physical activity and exercise induced OA; noninvasive mechanical loading (repetitive mild loading and single-impact injury); and surgically induced (meniscectomy models or anterior cruciate ligament transection). The specific model used would be based on the goal of the study.⁷ For example, OA pathophysiology, OA progression, and OA therapies studies could use spontaneous, genetic, surgical, or noninvasive models. In addition, pain studies could use chemical models. Lastly, post-traumatic studies would use surgical or noninvasive models; the most frequently used method is currently destabilization of the medial meniscus,³² which involves transection of the medial meniscotibial ligament, thereby destabilizing the joint and causing instability-driven OA. An important caveat for mouse models is that the mouse and human knee differ in terms of joint size, joint biomechanics, and histologic characteristics (layers, cellularity),^32,64 and joint differences could confound clinical translation.¹⁰ Table 1. Mouse models of osteoarthritis.

Stress-induced flowering

Many plant species can be induced to flower by responding to stress factors. The short-day plants Pharbitis nil and Perilla frutescens var. crispa flower under long days in response to the stress of poor nutrition or low-intensity light. Grafting experiments using two varieties of P. nil revealed that a transmissible flowering stimulus is involved in stress-induced flowering. The P. nil and P. frutescens plants that were induced to flower by stress reached anthesis, fruited and produced seeds. These seeds germinated, and the progeny of the stressed plants developed normally. Phenylalanine ammonialyase inhibitors inhibited this stress-induced flowering, and the inhibition was overcome by salicylic acid (SA), suggesting that there is an involvement of SA in stress-induced flowering. PnFT2, a P. nil ortholog of the flowering gene FLOWERING LOCUS T (FT) of Arabidopsis thaliana, was expressed when the P. nil plants were induced to flower under poor-nutrition stress conditions, but expression of PnFT1, another ortholog of FT, was not induced, suggesting that PnFT2 is involved in stress-induced flowering.Key words: flowering, stress, phenylalanine ammonia-lyase, salicylic acid, FLOWERING LOCUS T, Pharbitis nil, Perilla frutescensFlowering in many plant species is regulated by environmental factors, such as night-length in photoperiodic flowering and temperature in vernalization. On the other hand, a short-day (SD) plant such as Pharbitis nil (synonym Ipomoea nil) can be induced to flower under long days (LD) when grown under poor-nutrition, low-temperature or high-intensity light conditions.^1–9 The flowering induced by these conditions is accompanied by an increase in phenylalanine ammonia-lyase (PAL) activity.¹⁰ Taken together, these facts suggest that the flowering induced by these conditions might be regulated by a common mechanism. Poor nutrition, low temperature and high-intensity light can be regarded as stress factors, and PAL activity increases under these stress conditions.¹¹ Accordingly, we assumed that such LD flowering in P. nil might be induced by stress. Non-photoperiodic flowering has also been sporadically reported in several plant species other than P. nil, and a review of these studies suggested that most of the factors responsible for flowering could be regarded as stress. Some examples of these factors are summarized in 12^–14

Table 1

Some cases of stress-induced flowering