Morphological, physiological and biochemical observations on skate electric organ

Summary The electric organs of two species of skate have been examined morphologically, physiologically and biochemically. They can be easily dissociated into innervated or denervated component electrocytes by a Torpedo Ringer's solution containing 1% collagenase. Collagenase treatment did not, however, separate the Schwann cell cover capping the synaptosomes. Isolated electrocytes generate normal MEPP frequencies and show evoked responses for two days in Torpedo Ringer's. The nerve terminals retain excitability and transmitter release properties up to the time of separation. Since isolated terminals and denervated electrocytes show normal ultrastructural characteristics for up to 12 h, the skate electric organ provides several preparations which are not attainable with Torpedo tissue. Acetylcholine (ACh) content of supernatant fractions containing the synaptosomes was comparable to that found in Torpedo (sps.). Collagenase specifically eliminates the basal lamina associated with the synaptic junctional region. Neuronal cell death and synaptic terminal degeneration were also noted in the adult organs of both species. The skate electric organ is ideally suited for the study of cholinergic development and transmission.     

Premenstrual anxiety and depression: comparison of objective psychological tests with a retrospective questionnaire

Increased anxiety and depression are among the most frequently reported psychological problems in women seeking help for severe symptomatic premenstrual change, but there has been little objective evaluation of these symptoms. We therefore examined the results of objective psychological testing in 40 women with no apparent psychiatric or psychological disorder who had reported moderate to extreme increased anxiety and depression on a retrospective assessment form. Scores on the State-Trait Anxiety Inventory and Institute of Personality and Ability Testing (IPAT) Depression Scale increased from the low symptom intermenstrual phase of the cycle (days 5-10) to the premenstrual phase (within the last 6 days of the cycle), suggesting that retrospective complaints of increased premenstrual anxiety and depression can be confirmed on objective psychological assessment. However, it was observed that the distribution of intermenstrual IPAT depression scores was bimodal. Cyclic changes varied among the tests depending upon the IPAT depression score. The study suggests that 2 populations may exist in this screened sample; one population appears to have "pure PMS" and the second groups manifests a premenstrual exacerbation of subclinical depression.     

Cellular elements of the dermis and collagen remodelling during larval life of anurans

The differentiation of the collagenous dermis has been followed by electron microscopy in larvae of three anuran species. Events can be divided into five phases, depending on the organization of the cellular elements. Initial secretion of collagen appears to be from the epidermis but fibroblasts are present from early stages. Apart from secretion, there is phagocytosis of fibrils by fibroblasts, seen most frequently when the operculum is formed and at metamorphosis. In most larval stages, the dermis consists of regular plies of collagen fibrils, penetrated by processes from underlying fibroblasts and crossed by nerves, with a cellular layer defining the deep face. In Rana, these cells contain enormous vacuoles and have been called "compartmented cells", but the vacuoles are absent in Bufo and Xenopus. Just before metamorphosis, fibroblasts and chromatophores migrate into the dermis, and establish a stratum laxum. A few plies of larval collagen fibrils are left under the epidermis, the bulk of the larval dermis becomes the stratum compactum. During larval life, the hypodermis contains chromatophores, blood capillaries and wandering leucocytes. The dermis gains a blood circulation only at metamorphosis, when subdermal lymph sacs and vertical smooth muscles are established.     

Experience with osseous implants for bone and biomaterials research

A Cancellous Access Port (CAP) osseous implant for repeated sampling of cancellous tissue was developed and tested for experimental studies of bone, marrow, and materials biocompatibility. The CAP and associated methods were shown in a series of studies to allow the repeated biopsy of unstrained cancellous tissue with little morbidity and no mortality when used in baboons, rhesus, sheep, and horses. CAP infusion, material testing, and biopsy core assemblies were developed and tested for the administration and assessment of the effects of pharmaceuticals and biologics; the placement and retrieval of a biomaterial with the surrounding tissue; and studies of cancellous bone healing and remodeling.     

Achieving smoke-free hospitals. Tips for administrators

Almost thirty years have passed since the surgeon general of the United States released the first report on the effects of smoking (U.S. Department of Health, Education, and Welfare 1964). Over the ensuing years, further reports have expanded our knowledge of the widespread physiological effects of tobacco smoke and those at greatest risk (U.S. Department of Health, Education, and Welfare 1979; U.S. DHHS 1987, 1991, 1992; American Medical Association 1989). Subsequently, there has been a dramatic decrease in the number of smokers; more than thirty-six million Americans have quit smoking since the surgeon general's report (U.S. DHHS 1987, 7). Supporting this trend are the surgeon general's national health objectives for the year 2000 to achieve smoke-free work environments (Koop 1985). All of these trends contribute to current efforts to make hospitals smoke-free environments.     

Bile reflux and the gastric mucosa: an experimental ferret model

To study the effects of chronic bile reflux on the mammalian gastric mucosa, the ferret model was chosen for its practical aptitude and for its similarity to human gastric anatomy and physiology. A technique was first perfected for endoscopically directed gastric mucosal biopsy in the ferret. Subsequently, a surgical model of maximal enterogastric reflux (MR) and a control model of minimal reflux or "nonreflux" (NR) were developed. A stable population of 9 MR and 9 NR ferrets surviving 1-3 years has been established. All 18 animals, plus 6 nonoperative control animals, have undergone multiple repeat endoscopy and gastric biopsy without complication. The surgical and endoscopic techniques, with preliminary findings, are described.     

Some problems and some solutions in research on psychotherapeutic intervention in cancer

Several requirements of psychotherapeutic intervention (PI) research are presented. Some major problems are discussed. First, confidence in experimental results may be diminished by interference of possible confounders. A large number of these exist, both physical, perhaps more easily measurable, and psychological or psychosocial. Second, the value and limitations of randomization are presented, with special reference to small N. Validity and reliability are addressed, with emphasis on things that may dilute the strength of both of these measures. Natural remedies are proposed. Internal consistency and reliability are compared and cautions are given regarding their use and possible invalid substitution of consistency for reliability. Comparison of different PIs is commented on, with some relevant examples. Finally, a matter of special interest is discussed: the inconsistency between Spiegel's control survival curve and that produced from local population normative data.Presented at the Symposium Psychotherapeutic Interventions in Cancer Patients, Flims, Switzerland, 12–14 January 1995     

Symptomatic pulmonary complications from liquid acrylate embolization of brain arteriovenous malformations.

PURPOSETo describe symptomatic pulmonary emboli from brain arteriovenous malformation embolization with liquid acrylates and to analyze the reasons for these complications and describe preventive techniques.METHODSThe clinical records of 182 patients embolized with acrylate glue since 1978 for treatment of brain AVMs were searched for evidence of symptomatic pulmonary complications. Originally iso-butyl-2-cyanoacrylate and more recently n-butyl-2-cyanoacrylate were used in all patients. Arteriovenous malformation morphology, amounts and techniques of glue injection, and clinical and radiologic investigations in the symptomatic patients were recorded.RESULTSThree patients had pulmonary symptoms within 48 hours of glue injection. One patient with a left frontal arteriovenous malformation had embolization with an isobutyl-2-cyanoacrylate/pantopaque/acetic acid mixture; severe pleuritic chest pain developed 2 days later. One patient with a left temporal and one with a left cerebellar arteriovenous malformation had embolization with n-butyl-2-cyanoacrylate/lipiodol mixtures; a cough, pleuritic chest pain, and bloody sputum developed in both within 24 hours. Two patients experienced a significant drop in PO2. No flow-arrest techniques were used for any of the injections in these three patients. All patients demonstrated significant changes on chest x-ray and CT chest examinations. All were treated conservatively and recovered spontaneously.CONCLUSIONSSymptomatic pulmonary complications can occur after acrylate glue injection, particularly when delivery systems without flow arrest are used in high-flow vascular brain lesions. Techniques using acetic acid to delay polymerization time and "sandwich" techniques in which glue is pushed with dextrose are also more susceptible to this complication.