The Effects of Temperature on the Kinematics of Rattlesnake Predatory Strikes in Both Captive and Field Environments.

The outcomes of predator-prey interactions between endotherms and ectotherms can be heavily influenced by environmental temperature, owing to the difference in how body temperature affects locomotor performance. However, as elastic energy storage mechanisms can allow ectotherms to maintain high levels of performance at cooler body temperatures, detailed analyses of kinematics are necessary to fully understand how changes in temperature might alter endotherm-ectotherm predator-prey interactions. Viperid snakes are widely distributed ectothermic mesopredators that interact with endotherms both as predator and prey. Although there are numerous studies on the kinematics of viper strikes, surprisingly few have analyzed how this rapid movement is affected by temperature. Here we studied the effects of temperature on the predatory strike performance of rattlesnakes (Crotalus spp.), abundant new world vipers, using both field and captive experimental contexts. We found that the effects of temperature on predatory strike performance are limited, with warmer snakes achieving slightly higher maximum strike acceleration, but similar maximum velocity. Our results suggest that, unlike defensive strikes to predators, rattlesnakes may not attempt to maximize strike speed when attacking prey, and thus the outcomes of predatory strikes may not be heavily influenced by changes in temperature.

Characterization of alterations in plasma lipoprotein lipid and apoprotein profiles accompanying hepatoma-induced hyperlipidemia in rats.

Alterations in plasma lipoprotein lipid and apoprotein accompanying the hyperlipidemia of rats bearing Morris hepatoma 7288C were characterized. In tumor-bearing animals all plasma lipid classes except cholesterol ester (CE) were elevated, particularly free cholesterol (FC) and triglyceride (TG), which increased by 57 and 63%, respectively. Fasting only partially reduced the tumor-induced hyperlipidemia and had no effect on the ratios of FC/CE and TG/CE. Analysis of plasma lipoproteins revealed an elevation of VLDL, IDL, and LDL in host rats, with more than a 2-fold increase in both lipid and protein of VLDL. In contrast, the three high density fractions, HDL2, HDL3, and d greater than 1.21 g/ml, were reduced. The inverse changes in concentration of host lipoproteins of lower versus higher density indicate a defective catabolism of TG-rich lipoprotein. This possibility is supported by the analysis of apolipoprotein. The percentage of total apoprotein contributed by apo C-I and C-II was reduced in all host fractions except HDL2, while the C-IIIs remained unchanged except for a small decrease in C-III-3 of host VLDL and a slight increase in the combined C-IIIs of HDL2. These changes were reflected in the decreased C-I+C-II/C-III ratios of all host lipoprotein fractions. Apo E levels remained similar to control values except for a significant decrease in HDL2. Host VLDL showed increased apo A-IV and A-I content, while A-IV was decreased in HDL2. Changes in apo B profiles were also observed.

Role of lipid transfer proteins in the abnormal lipid content of Morris hepatoma mitochondria and microsomes.

The level of nonspecific lipid transfer protein in three Morris hepatomas of varying degrees of differentiation has been found to be less than 10% of the level in either host or control livers, whereas phosphatidylcholine transfer activity is slightly reduced for hepatomas compared to host livers (20 to 40%), though nearly the same as levels present in livers of non-tumor-bearing rats. Two major differences have been observed in the lipid compositions of tumor mitochondrial and microsomal membranes compared to those of normal membranes. For all three hepatomas, the cholesterol content of mitochondria is markedly elevated, and the phospholipid content of microsomes is reduced (per mg of protein). As a consequence of the above alterations, the cholesterol: phospholipid ratio of both the microsomal and mitochondrial membranes of these tumors is increased, and the extent of this increase correlates well with the degree of differentiation of the hepatomas. If an important physiological role of lipid transfer proteins is to transfer newly synthesized lipids from microsomes to other cellular organelles, one would expect a 10-fold decline of nonspecific lipid transfer protein activity in hepatomas to result in phospholipid and cholesterol accumulation in microsomes and depletion in mitochondria. The observed decline of phospholipid in microsomes and accumulation of cholesterol in mitochondria from hepatomas suggest that this is not an important function of the nonspecific lipid transfer protein. Finally, preliminary studies of the possibility that the elevated cholesterol: phospholipid levels in hepatoma membranes affect the activities of enzymes of these membranes are reported.

Calculation of s20,w values using ultracentrifuge sedimentation data from linear sucrose gradients, an improved, simplified method.

A mathematical method is described for calculating the sedimentation coefficient (S20,W) with ultracentrifuge data from linear sucrose gradients. Gradient density and viscosity functions are precisely described by regression equations, which permit continuous evaluation (by integration) of the effects of gradient geometry on particle sedimentation. The results agree with previously used and more complex methods.

The sucrose gradient and native DNA S20,W, an examination of measurement problems.

Sedimentation coefficients of T7, T2H AND T4 DNA were determined with isokinetic sucrose gradients in both 0.1 M and 1 M NaCl. The s values were completely equivalent to those measured by analytical ultracentrifuge and no reduction of s20,w was observed due to the presence of sucrose (anomalous sedimentation). s20,w values are calculated on the basis of both partial specific volume (v) and apparent specific volume (0). Using the latter value s20,w molecular weight relations are derived for 0.1 M and 1 M NaCl solvents. The glucosylation of T2H and T4 DNA appears to influence s20,w in a manner disproportionate to the molecular weight added by glucose.

Modeling of clusters in a strong 248-nm laser field by a three-dimensional relativistic molecular dynamic model.

A relativistic time-dependent three-dimensional particle simulation model has been developed to study the interaction of intense ultrashort KrF (248 nm) laser pulses with small Xe clusters. The trajectories of the electrons and ions are treated classically according to the relativistic equation of motion. The model has been applied to a different regime of ultrahigh intensities extending to 10(21) W/ cm(2). In particular, the behavior of the interaction with the clusters from intensities of approximately 10(15) W/cm(2) to intensities sufficient for a transition to the so-called "collective oscillation model" has been explored. At peak intensities below 10(20) W/cm(2), all electrons are removed from the cluster and form a plasma. It is found that the "collective oscillation model" commences at intensities in excess of 10(20) W/cm(2), the range that can be reached in stable relativistic channels. At these high intensities, the magnetic field has a profound effect on the shape and trajectory of the electron cloud. Specifically, the electrons are accelerated to relativistic velocities with energies exceeding 1 MeV in the direction of laser propagation and the magnetic field distorts the shape of the electron cloud to give the form of a pancake.

Sleep-induced ventilatory dysfunction in Down's syndrome.

Three patients with Down's syndrome demonstrated severe sleep-induced ventilatory failure characterized by Cheyne-Stokes respiration with superimposed obstruction of the upper airway. Anatomic otolaryngologic factors were present in two of the three patients, implicating both mechanical and CNS factors in the pathogenesis of this phenomenon. Administration of protriptyline hydrochloride elicited considerable improvement in one case. Occult sleep-related ventilatory failure may account for the previously unexplained tendency for pulmonary hypertension to develop in patients with Down's syndrome.

Protriptyline: an effective agent in the treatment of the narcolepsy-cataplexy syndrome and hypersomnia.

The authors present five case reports illustrating that 10-20 mg of protriptyline in a single dose at bedtime can effectively control arousal dysfunction (sleep drunkenness and hypersomnia) and the narcolepsycataplexy syndrome without the apparent development of tolerance and without the side effects that are frequent complications of treatment with other agents. Although protriptyline was efficacious in controlling symptoms, it was found to have relatively poor REM sleep-suppressing properties.

Adrenergic hyperactivity and cardiac abnormality in primary disorders of sleep.

Symptoms suggesting autonomic instability and increased adrenergic effect were identified in 53 patients with primary disorders of impaired wakefulness. Urine and plasma catecholamine concentrations were significantly increased in patients with sleep apnea. Excessive increases in heart rate during isoproterenol infusions suggested adrenergic hyperresponsiveness as an alternative explanation for symptoms of catecholamine excess in some individuals. Twenty-two patients demonstrated mitral valve prolapse (MVP), implicating primary neurologic disturbances as potential factors in the fatigue and lassitude often associated with MVP. The catecholamine abnormalities may explain some of the difficulties frequently encountered in using stimulants to treat sleep disorders.

Disordered growth hormone and prolactin secretion in primary disorders of sleep.

Growth hormone (GH) and prolactin (PR) secretion were evaluated in 28 patients who had sleep apnea or narcolepsy but no other primary neurologic or endocrine disorders. Eighty-one percent of subjects with impaired alertness failed to demonstrate serum GH concentrations in excess of 5 ng per milliliter following oral administration of L-DOPA, 500 mg. Diminished GH responses to sleep and intravenous arginine were observed in 57 percent and 44 percent, respectively, of patients tested. Sleep-related PRL release was less than normal in women with narcolepsy, with or without sleep apnea. All patients had at least one abnormality in GH or PRL secretion.

Sleep apnea: treatment with protriptyline.

Fourteen patients with an average of more than 60 episodes of upper airway obstruction during night sleep were treated with a nonsedating tricyclic antidepressant, protriptyline. Frequency and duration of recorded apneas decreased in 11 cases, and satisfactory control of sleep apnea was maintained with medical therapy alone in 8 of these 11 patients for 7 to 15 months. Potential adverse effects of protriptyline, particularly on the cardiovascular system, limit its use in this illness. These results indicate the possibility of pharmacologic reversal of sleep-induced incoordination of the upper airway.

Inhibition of cholesteryl ester transfer protein activity in hamsters alters HDL lipid composition.

We investigated the role of cholesteryl ester transfer protein (CETP) in hamsters by using a monoclonal antibody (MAb) that inhibited hamster CETP activity. MAbs were prepared against partially purified human CETP and screened for inhibiton of 3H-cholesteryl oleate (CE) transfer from LDL to HDL in the presence of human plasma bottom fraction (d > 1.21 g/ml). Antibody 1C4 inhibited CE transfer activity in both human plasma bottom fraction (IC50 = approximately 4 micrograms/ml) and in whole plasma from male Golden Syrian hamsters (IC50 = approximately 30 micrograms/ml). Purified MAb 1C4 was injected into chow- and cholesterol-fed hamsters, and blood was collected for analysis of plasma CETP activity and HDL lipid composition. Plasma CETP activity was inhibited by 70%-80% at all and HDL lipid composition. Plasma CETP activity was inhibited by 70%-80% at all times up to 24 h following injection of 500 micrograms MAb 1C4 (approximately 3.7 mg/kg). The amount of antibody required for 50% inhibition at 24 h post-injection was 200 micrograms (approximately 1.5 mg/kg). Inhibition of hamster CETP activity in vivo increased hamster HDL cholesterol by 33% (P < 0.0001), increased HDL-CE by 31% (P < 0.0001) and decreased HDL-triglyceride by 42% (P < 0.0001) (n = 36) as determined following isolation of HDL by ultracentrifugation. An increase in HDL cholesterol and a redistribution of cholesterol to a larger HDL particle were also observed following fast protein liquid chromatography (FPLC) gel filtration of plasma lipoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute mastoiditis in children: a review of 54 cases.

Fifty-four children with acute mastoiditis were managed at the Los Angeles County-University of Southern California Medical Center from 1972 through 1982. Our criteria for the diagnosis of acute mastoiditis are acute or subacute otitis media, postauricular swelling and erythema, protrusion of the auricle, and clouding of mastoid air cells on radiographs. Thirty-one (57%) recovered with conservative therapy consisting of early myringotomy and intravenous antibiotic, usually ampicillin. Twenty-three patients were managed surgically. The indication for surgery in each case was the clinical diagnosis of subperiosteal abscess; mastoid radiographs played no part in the decision to operate. Two of the 23 patients managed surgically had only incision and drainage of abscess; simple mastoidectomy was performed on 20 and radical mastoidectomy on one. Etiologic bacteria were cultured in 21 instances, S. pyogenes was cultured in 9, S. pneumoniae was cultured in 6, H. influenzae in 1, enterococci in 1, anaerobes in 2, and M. tuberculosis in 2.

Videoendoscopic determination of the mechanism of obstruction in obstructive sleep apnea.

Six patients with obstructive sleep apnea were studied with our system of simultaneous video recording of the polysomnographic record and the endoscopic image from the pharyngeal airway. Preoperative and postoperative recordings were made during sleep in each patient. Tracheotomized patients recreated their preoperative laryngeal inlet obstruction and its immediate cessation by alternately opening and closing the tracheotomy tube. This demonstration coupled with the physical examination findings of "disproportionate anatomy," leads to the determination that the mechanism of obstructive sleep apnea is twofold: (1) an underlying CNS propensity to hypotonia of pharyngeal musculature during sleep and (2) either an isolated obstructive upper airway lesion or a combination of alterations in normal relationships within the upper airway that cause a passive narrowing of the upper airway. This combination of altered relationships is collectively referred to as "disproportionate anatomy."

Flexible laryngoscopy in neonates, infants, and young children.

Flexible laryngoscopy was performed 453 times on 264 patients 4 years of age or younger. Sixty-five percent were under 6 months of age. Stridor was the indication for laryngoscopy in 60% of the patients. Problems secondary to intubation and poor voice each were indications in 12%. The most common finding was laryngomalacia, followed by laryngeal edema, normal larynges, and vocal cord paralysis or paresis. Subglottic stenosis was diagnosed in 17 patients. Flexible laryngoscopy is a relatively noninvasive, safe, and effective technique for examining the larynx of infants and young children.

Orbital involvement in acute sinusitis. Lessons from 24 childhood patients.

The possibility of acute bacterial sinusitis should be considered in any child with sudden swelling about the orbit. Management is determined by the stage of the disease as well as by the sinus predominantly involved. Extraocular movements and proptosis are the best guidelines for therapy. When there is no proptosis and extraocular mobility is normal, conservative therapy with intravenous antibiotics and nasal decongestants is usually effective. When ocular mobility is impaired or proptosis develops, intranasal or external surgical drainage are usually required. Of 24 patients summarized in this paper, the ethmoid was the predominantly involved sinus in 12, the frontal in 7, the maxillary in 5. Only 4 of the 12 with predominant ethmoiditis required surgery. All 7 were predominant frontal involvement needed surgical drainage.

The Pope's confessor: a metaphor relating to illness in the analyst.

This paper examines some of the internal and external eventualities in the situation of illness in the analyst. The current emphasis on the use of the self as part of the analyzing instrument makes impairments in the analyst's physical well-being potentially disabling to the analytic work. A recommendation is made for analysts, both individually and as a professional group, to always consider this aspect of a personal medical problem.