Bowen disease with invasive mucin-secreting sweat gland differentiation: Report of a case and review of the literature.

Bowen disease (BD) with divergent adnexal differentiation is a rare composite cutaneous tumor featuring different phenotypic elements. Sebaceous, poroid and trichilemmal invasive components have been described in this setting and very infrequent reports of mucinous glandular differentiation are extant. Clinically, these tumors are not sufficiently distinctive to enable recognition without histopathological evaluation.

Development of a high speed laser scanning confocal microscope with an acquisition rate up to 200 frames per second.

There has been an increasing interest for observing fast biological phenomena such as cell movements in circulations and action potentials. The laser scanning confocal microscopy offers a good spatial resolution and optical sectioning ability to observe various in vivo animal models. We developed a high speed laser scanning confocal microscope capable of acquiring 512 by 512 pixel images at 200 fps (frames per second).

Metabolic arrest and its regulation in anoxic eel hepatocytes.

Some vertebrates depress overall metabolism in an abrupt and reversible fashion when challenged with anoxia, ensuring stabilization of cellular [ATP] and long-term survival, but little is known about the eliciting stimuli (e.g., change in O2, adenylates) and downstream effectors responsible for metabolic arrest.

Exclusive involvement of folliculosebaceous units by herpes: a reflection of early herpes zoster.

The histopathological changes of herpes simplex, herpes zoster, and varicella are considered to be indistinguishable from one another. Evaluation of the clinical setting, with adjunctive studies if necessary, generally clarifies the specific diagnosis. Vesicular lesions in all three conditions can involve epidermal and adnexal epithelium with characteristic cytopathic features.

Metaplastic breast carcinoma: clinical-pathologic characteristics and HER2/neu expression.

Background: Metaplastic breast carcinomas (MBC) are rare primary breast malignancies characterized by the co-existence of carcinoma with non-epithelial cellular elements. They can be classified as monophasic spindle cell (sarcomatoid) carcinoma, biphasic carcinosarcoma, adenocarcinoma with divergent stromal differentiation (osseous, chondroid and rarely rhabdoid) as well as adenosquamous and pure squamous cell carcinomas. There is a paucity of information on clinically relevant pathologic features and clinical outcomes for these rare tumors.

Environmental hypoxia does not constrain the diurnal depth distribution of free-swimming Nautilus pompilius.

The behaviour of Nautilus pompilius swimming freely in a controlled mesocosm (tower tank, 4 m diameter x 10.5 m deep) was monitored using ultrasonic depth telemetry. Initially depths were monitored in water equilibrated with air.

Adaptive plasticity of skeletal muscle energetics in hibernating frogs: mitochondrial proton leak during metabolic depression.

The common frog (Rana temporaria) spends the coldest months of each year overwintering in ice-covered ponds where temperatures can vary from 0.5 to 4.0 degrees C.

Mechanisms of metabolic defense against hypoxia in hibernating frogs.

The cold submerged frog (Rana temporaria) serves as a useful model for many hibernating ectotherms that take refuge in hypoxic ponds and lakes until more favourable conditions of climate and food availability return. In all such animals, entry into a hypometabolic state effectively extends their survival time by lessening the impact of ATP demands on endogenous substrates. At the cellular level, metabolic depression may be brought about by decreasing energy-consuming processes and/or by increasing the efficiency of energy-producing pathways.

Caudal differential pressure as a predictor of swimming speed of cod (Gadus morhua).

We report the results of an experiment designed to investigate the feasibility of using differential pressure to estimate the swimming speed and metabolic rate of Atlantic cod (Gadus morhua). Seven cod were fitted with a miniature differential pressure sensor mounted on one side of the caudal peduncle immediately anterior to the base of the caudal fin rays. Relationships between differential pressure, tailbeat frequency, tailbeat amplitude, swimming speed and rate of oxygen consumption ((O(2))) were determined as a function of the swimming speed of cod swimming at 5 degrees C in a recirculating 'Brett-style' respirometer.

Mechanisms of cell survival in hypoxia and hypothermia.

Most animals experience some degree of hypoxia and hypothermia during the course of their natural life history either as a consequence of ambient 'exposure' per se or through metabolic, respiratory and/or circulatory insufficiency. A prevailing experimental approach has been to probe tissues from natural models of hypoxia-tolerant and cold-tolerant vertebrates to look for common mechanisms of defence against O(2) lack and hypothermia. The ability to sustain vital cellular functions in severe cases of either condition varies widely amongst the vertebrates.

Unsteady-state gas exchange and storage in diving marine mammals: the harbor porpoise and gray seal.

Breath-by-breath measurements of end-tidal O(2) and CO(2) concentrations in harbor porpoise reveal that the respiratory gas exchange ratio (R(R); CO(2) output/O(2) uptake) of the first lung ventilation in a breathing bout after a prolonged breath-hold is always well below the animal's metabolic respiratory quotient (RQ) of 0.85. Thus the longest apneic pauses are always followed by an initial breath having a very low R(R) (0.

Strategies of hypoxia and anoxia tolerance in cardiomyocytes from the overwintering common frog, Rana temporaria.

Using ventricular cardiomyocytes of the common frog, Rana temporaria, we investigated the metabolic strategies employed by the heart to tolerate 4 mo of hypoxic submergence (overwintering) as well as acute bouts of anoxia. In contrast to what is observed for the whole animal, there was no change in oxygen consumption in cardiomyocytes isolated from normoxic frogs compared with those isolated from 4-mo hypoxic animals. Furthermore, cells from both normoxic and hypoxic frogs were able to completely recover oxygen consumption following 30 min of acute anoxia.

Aerobic capacity of frog skeletal muscle during hibernation.

Frogs submerged at 3 degrees C in hypoxic water (Po2=60 mmHg) depress their metabolic rate to 25% of that seen in control animals with access to air. The hypometabolic state of the skeletal muscle in such cold-submerged frogs is thought to be the most important contributor to the overall metabolic depression. The aim of this study was to determine whether the aerobic capacity of frog skeletal muscle became altered during 1-4 mo of hibernation to match the reduction in adenosine triphosphate (ATP) demand.

Isolation by distance in the Atlantic cod, Gadus morhua, at large and small geographic scales.

Genetic isolation by distance (IBD) has rarely been described in marine species with high potential for dispersal at both the larval and adult life-history stages. Here, we report significant relationships between inferred levels of gene flow and geographic distance in the Atlantic cod, Gadus morhua, at 10 nuclear restriction-fragment-length-polymorphism (RFLP) loci at small regional scales in the western north Atlantic region (< 1,600 km) that mirror those previously detected over its entire geographic range (up to 7,300 km). Highly significant allele frequency differences were observed among eight northwestern Atlantic populations, although the mean FST for all 10 loci was only 0.

Merkel cell carcinoma: squamous and atypical fibroxanthoma-like differentiation in successive local tumor recurrences.

Merkel cell carcinoma (MCC) is a rare, frequently lethal, primary neuroendocrine carcinoma of the skin. Histopathologically, it appears as a dermal nodule of small, undifferentiated malignant cells. Historically, MCC was considered to be an eccrine carcinoma.

Metabolic depression and enhanced O(2) affinity of mitochondria in hypoxic hypometabolism.

This study examined whether the steady-state hypometabolism seen in overwintering frogs (Rana temporaria) is reflected at the mitochondrial level either by a reduction in their resting (state 4) and active (state 3) respiration rates and/or by increases in O(2) affinity. We isolated mitochondria from the skeletal muscle of cold-submerged frogs at different stages during their hibernation in normoxic and hypoxic water. A modest metabolic depression at the whole animal level (normoxic submergence) was not associated with a reduction in mitochondrial state 4 and state 3 respiration rates.

Surviving hypoxia without really dying.

In cases of severe O(2) limitation, most excitable cells of mammals cannot continue to meet the energy demands of active ion transporting systems, leading to catastrophic membrane failure and cell death. However, in certain lower vertebrates, hypoxia-induced membrane destabilisation of the kind seen in mammals is either slow to develop or does not occur at all owing to adaptive decreases in membrane permeability (i.e.

The protective effects of hypoxia-induced hypometabolism in the Nautilus.

Specimens of Nautilus pompilius were trapped at depths of 225-300 m off the sunken barrier reef southeast of Port Moresby, Papua New Guinea. Animals transported to the Motupore Island laboratory were acclimated to normal habitat temperatures of 18 degrees C and then cannulated for arterial and venous blood sampling. When animals were forced to undergo a period of progressive hypoxia eventually to encounter ambient partial pressure of oxygen (PO2) levels of approximately 10 mmHg (and corresponding arterial PO2's of approximately 5 mmHg), they responded by lowering their aerobic metabolic rates to 5-10% of those seen in resting normoxic animals.

Mitochondria as ATP consumers: cellular treason in anoxia.

In anoxia, mitochondria change from being ATP producers to potentially powerful ATP consumers. This change occurs, because the mitochondrial F(1)F(0)-ATPase begins to hydrolyze ATP to avoid the collapse of the proton motive force. Species that can survive prolonged periods of O(2) lack must limit such ATP use; otherwise, this process would dominate glycolytic metabolism and threaten ATP delivery to essential ATP-consuming processes of the cell (e.

Effects of ambient PO2 and temperature on oxygen uptake in Nautilus pompilius.

This study employs closed-circuit respirometry to evaluate the effect of declining ambient oxygen partial pressure (PO2) and temperature on mass specific rates of oxygen uptake (VO2) in Nautilus pompilius. At all temperatures investigated (11, 16, and 21 degrees C), VO2 is relatively constant at high PO2 (oxyregulation) but declines sharply at low PO2 (oxyconformation). The critical PO2 below which oxyconformation begins (Pc) is temperature dependent, higher at 21 degrees C (49 mmHg) than at 11 degrees C or 16 degrees C (21.

The effect of metabolic depression on proton leak rate in mitochondria from hibernating frogs.

Futile cycling of protons across the mitochondrial inner membrane accounts for 20 % or more of the total standard metabolic rate of a rat. Approximately 15 % of this total is due to proton leakage inside the skeletal muscle alone. This study examined whether the rate of proton leak is down-regulated as a part of a coordinated response to energy conservation during metabolic depression in cold-submerged frogs.

Gas exchange and heart rate in the harbour porpoise, Phocoena phocoena.

The respiratory physiology, heart rates and metabolic rates of two captive juvenile male harbour porpoises (both 28 kg) were measured using a rapid-response respiratory gas analysis system in the laboratory. Breath-hold durations in the laboratory (12 +/- 0.3 s, mean +/- SEM) were shorter than field observations, although a few breath-holds of over 40 s were recorded.

Factors affecting membrane permeability and ionic homeostasis in the cold-submerged frog.

Frogs (Rana temporaria) were submerged at 3 degrees C in either normoxic (P(O2)=155 mmHg, P(O2)=20 kPa) or hypoxic (P(O2)=60 mmHg; P(O2)=8 kPa) water for up to 16 weeks, and denied air access, to mimic the conditions of an ice-covered pond during the winter. The activity of the skeletal muscle Na(+)/K(+) pump over the first 2 months of hibernation, measured by ouabain-inhibitable (22)Na(+) efflux, was reduced by 30 % during normoxia and by up to 50 % during hypoxia. The reduction in Na(+)/K(+) pump activity was accompanied by reductions in passive (22)Na(+) influx and (86)Rb(+) efflux (effectively K(+) efflux) across the sarcolemma.