Oral ontogeny of the Ayu, Plecoglossus altivelis and comparisons with the jaws of other salmoniform fishes

The Japanese Ayu, Plecoglossus altivelis Temminck & Schlegel is the sole representative of the salmoniform family Plecoglossidae. The Ayu is remarkable for its dentition which in adults comprises groups of diagonally arranged comb-like teeth in the outer tissue of the jaws. In juveniles (below 63 mm SL) the teeth are attached normally to the jaws. The transition of tooth form is correlated with a switch from zooplanktivory to algal or aufwuchs grazing. The present study follows the development of the teeth, jaws, oral cavity ethmoid and suspensorial elements in specimens ranging in size from 41–70 mm SL. The possible mode of function of the adult dentition is discussed. Comparisons are made with the jaws of other salmoniform fishes and a suite of supposed apomorphic characters are identified which are also shared with certain genera of the family Osmeridae, thus supporting the ideas of others that the Osmeridae is a paraphyletic assemblage.     

Endocrine function of the heart. Structure and biological properties of peptides secreted by the heart atrium

Apart from the generally known functions, the heart has also an endocrine function. Atrial cardiocytes, being typical secretory cells, release peptide hormones into the blood stream: atrial natriuretic peptide containing 28 amino acids and cardiodilatin. The structure of atrial peptides was determined. It was shown that both peptides were derived from their common precursor, a protein containing 151 amino acids. The presence of specific receptors is demonstrated on plasmatic membranes of cells of kidney epithelium, arterial smooth muscle, arterial endothelium, kidney cortex and hypophysis. The interaction of atrial peptides with these receptors activates the guanylate cyclase system. The biological action of atrial peptides manifests itself in the quick, massive and instantaneous increase of diuresis and electrolyte excretion, elevated clearance of creatinine, decrease of kidney vascular resistance, intensification of glomerular filtration, inhibition of stimulated secretion of aldosterone, relaxation of blood vessels, elimination of arterial and intestinal spasm induced by various endogenous and exogenous vasoconstrictors and in correction of kidney hypertension. Various radioimmunoassays for the presence of atrial peptides in human plasma were developed; it was shown that in patients with congestive heart failure the content of atrial peptides is increased.     

The right ventricular working heart preparation

An isolated working rat heart preparation was modified to study right ventricular (RV) performance. All hearts were perfused with a Krebs-Henseleit bicarbonate buffer via a Langendorff column at 90 mm Hg. Right atrial filling (preload) was varied by raising a buffer reservoir from 5 cm below to 10 cm above the right atrium while pulmonary artery outflow resistance remained fixed. RV systolic pressure and the maximum rise and decrease in pressure development (+/- dP/dt) were measured via a catheter in the RV. Cardiac output was collected with a catheter placed in the pulmonary artery. One group of hearts, monitored at a fixed preload (0 cm H2O) for 2 hr, and another group of hearts, in which two ventricular function curves were performed, demonstrated the stability and reproducibility of the preparation. Additionally, the ability of this preparation to measure changes in inotropy was studied. A negative inotropic effect was measured after verapamil (5 X 10(-8) M) treatment. Positive dP/dt showed the greatest depression (30%) and was significantly lower at every preload. A positive inotropic effect was demonstrated by reducing the buffer Ca2+ concentration to 1.9 mM for the first work curve followed by an addition of Ca2+ (2.8 mM final concentration) or ouabain (5 X 10(-5) M) for the second work curve. Again, the greatest effect was found in the dP/dt measurements (elevated by 20 and 30%, respectively). Thus, this preparation manifests qualities similar to those used in studying the left ventricle and allows investigation of various cardiac diseases which may affect RV pump function.     

A homologous radioimmunoassay for guinea pig corticosteroid-binding globulin

A rapid, specific, and sensitive (requiring only 20 fmole of antigen equivalent to 0.007 microliter of serum) radioimmunoassay (RIA) was developed for the measurement of guinea pig corticosteroid-binding globulin (CBG). CBG was purified to homogeneity from guinea pig serum by affinity chromatography and used for immunization, as the standard and as the radiolabeled trace in the RIA. The antiserum to CBG was raised in rabbits. It was judged specific by immunoelectrophoresis and by comparison of RIA values with steroid-binding assay profiles obtained on serum separated on the basis of size and ion-exchange properties. The results of the radioimmunoassays agree with those of a steroid-binding assay run on identical samples. The sensitivity of the assay allows detection of CBG in serial serum samples, other biologic fluids such as milk, and cell culture supernatants.     

Effects of P-fertilization and inoculation by two vesicular-arbuscular mycorrhizal fungi on growth and nodulation ofCalopogonium caeruleum

The growth response ofCalopogonium caeruleum, a leguminous covercrop in plantation agriculture, to inoculation with two vesicular-arbuscular mycorrhizal (VAM) fungi was investigated in five phosphorus (P)-deficient soils supplied with various levels of rock phosphate. Significant shoot yield increases over the uninoculated controls were obtained in most sterilised or unsterilised soils at all applied P levels, although the inoculant VAM fungi differed in their effectiveness in the soils used. Responses in mycorrhizal root infections, P and nitrogen (N) concentrations in tops and plant nodulation varied. The results are discussed in relation to the edaphic environment of the mycorrhizal association.     

Ice Encasement Injury to Microsomal Membranes from Winter Wheat Crowns : I. Comparison of Membrane Properties after Lethal Ice Encasement and during a Post-Thaw Period

The functional and physical properties of cellular membranes isolated from Triticum aestivum, cvs Norstar and Fredrick, were altered coincident with changes in composition after a lethal ice-encasement stress and further during a 6 hour post-thaw period. Crowns encased in ice for a duration which inhibited regrowth, exhibited enhanced rates of electrolyte leakage. Furthermore, the recovery of total microsomal protein and phospholipid declined, suggesting that some membrane degradation had been induced during the anoxic stress. The microviscosity of microsomes and liposomes prepared from such membranes increased during stress, and this was correlated with a 2- to 4-fold increase in the free fatty acid levels in the microsomal fraction. There was, however, only a relatively minor change in fatty acid unsaturation during the ice-encasement stress. The process continued during a 6 hour aerobic post-thaw treatment, but the pattern was somewhat different. During this phase, the leakage of electrolytes was further increased and the recovery of microsomal protein and phospholipid continued to decline, indicating general degradation; but, in contrast to the anoxic phase, the degree of fatty acid unsaturation declined markedly, indicating lipid peroxidation.     

Hynes pharyngoplasty revisited

The treatment of velopharyngeal incompetence remains unsatisfactory because the causes are many, as are the variations in anatomic and physiologic defects. Therefore, full assessment and investigation are essential in tailoring the surgery to the defect. A modified Hynes pharyngoplasty has been used in 40 patients, aged 4 to 52, over a 4-year period for velopharyngeal incompetence of varying etiologic causes. Speech was assessed before and at least 6 months after pharyngoplasty. At the same time, radiologic and, when possible, nasendoscopic investigations were undertaken. Thirty-eight patients had no or variable nasal escape (variable defined as achieving intermittent closure), whereas 33 had normal or slight hyponasal resonance. There was only one complication, an asymptomatic dehiscence of the "bucket handle" flap from the posterior wall. Thirteen patients had an assortment of side effects, none requiring surgical treatment. We believe that patients who are suitable for the described sphincter pharyngoplasty are those with slight or moderate nasal escape having a mobile palate with an anteroposterior gap of 5 mm or less.     

The effects of ionizing radiation on the pulmonary vasculature of intact rats and isolated pulmonary endothelium

We studied the effects of ionizing radiation on the morphology of the pulmonary circulation using an in vivo rat model and an in vitro pulmonary artery endothelial cell model. Gamma radiation was given as either an acute (30 Gy) or fractionated (5 X 6 Gy) dose to one hemithorax of rats. An acute 30-Gy dose delivered resulted in a 70% decrease in pulmonary arterial perfusion, using technetium-99m microaggregated albumin (99mTc-MAA), in the irradiated lung by 2-3 weeks after irradiation. Pulmonary microradiographs, using a barium sulfate perfusion method, obtained 2-3 weeks after irradiation demonstrated widespread loss of capillary filling and segmentation of the vessels. Histologic examination demonstrated intact capillaries, suggesting that the alterations in pulmonary perfusion were at the precapillary level. Similar abnormalities in lung perfusion and morphology were found after delivery of fractionated doses of radiation, but the onset of the changes was delayed, occurring 4-6 weeks postirradiation. Using cultured pulmonary endothelial cell monolayers, cell sloughing and retraction from the surface substrate were observed within 24 h after in vitro delivery of 30 Gy. Similar findings occurred in monolayers given fractionated doses (5 X 6 Gy) of radiation 2-3 days after the final dose. The in vivo animal and in vitro endothelial cell models offer a useful means of examining the morphologic alterations involved in radiation lung vascular damage.     

Catecholamine content and acetylcholinesterase activity in the brain of rats exposed to lasers

The catecholamine content was quantitated and acetylcholinesterase activity determined in rat brain locally exposed to laser radiation. It was shown that the adrenaline/noradrenaline ratio changed in the tissues under study and the cholinergic system was involved in the abscopal effect of laser radiation.