Intracage ammonia promotes growth of Mycoplasma pulmonis in the respiratory tract of rats.

Ammonia (NH3) from soiled cage bedding is known to enhance the progression and severity of murine respiratory mycoplasmosis in rats. To test the hypothesis that NH3 directly or indirectly enhances the growth of Mycoplasma pulmonis in vivo, pathogen-free F344 rats were inoculated intranasally with 1 x 10(4) to 4 x 10(4) or 4 x 10(6) to 5 x 10(6) colony-forming units of M. pulmonis and exposed to less than or equal to 1.5 or 76 microgram of NH3 per liter (less than or equal to 2 or 100 ppm, respectively). Nasal passages, larynges, tracheas, and lungs from rats killed at intervals up to 28 days after inoculation were quantitatively cultured. Growth of M. pulmonis was much greater in NH3-exposed rats than in controls, particularly in those inoculated with the lower dose. Increases in M. pulmonis populations were more rapid in proximal airways than in distal airways. Serum immunoglobulin G and M antibody responses to M. pulmonis as measured by an enzyme-linked immunosorbent assay were greater in NH3-exposed rats. In other experiments, the nasal passages absorbed virtually all NH3 when the rats were exposed to less than 380 micrograms of NH3 per liter (500 ppm), indicating that NH3 induced increases in the numbers of organisms in the distal respiratory tract, probably by a secondary, rather than a direct, effect. Also, NH3 exposure did not inhibit pulmonary antibacterial activity as measured by clearance of radiolabeled Staphylococcus epidermidis. The growth of M. pulmonis in vitro was inhibited by 1 mM NH4+ added to the medium as NH4OH but not by NH4+ concentrations of 0.5, 0.1, or 0.01 mM, suggesting that NH3 increases growth indirectly through effects on the host.     

Characteristics of very poor outcome schizophrenia

The authors compared 21 "Kraepelinian" schizophrenic patients who had been ill and dependent on others for the past 5 years with 76 chronic schizophrenic patients in remission or with exacerbations requiring hospitalization. The Kraepelinian patients met the criteria for schizophrenia by more diagnostic systems than the exacerbated patients, were less responsive to haloperidol, had more severe negative symptoms, and had similarly severe positive symptoms. They had cerebral ventricles that were more asymmetrical and a greater family history of schizophrenia spectrum disorders than the other chronic patients. These data suggest that patients with 5 years of illness and complete dependency on others may represent a subgroup of schizophrenia.     

EFFECT OF NITROGLYCERNE-INDUCED HYPOTENSION ON CANINE SPINAL CORD BLOOD FLOW

Twenty-four mongrel dogs were anaesthetized with pentobarbitoneand morphine sulphate. Neuromuscular blockade was achieved usingpancuronium. Spinal cord blood flow was measured using the radionuclidemicrosphere and hydrogen washout methods before, during, andfollowing nitroglycerine-induced hypotension. Heart rate, meanarterial pressure, cardiac output, pulmonary capillary wedgepressure, and acid-base balance were determined with each measurement.Mean arterial pressure was reduced by 50%. Spinal cord bloodflow, as measured by the microsphere method, increased duringthe period of hypotension, whereas values obtained using thehydrogen washout method were not significantly different fromthose at normotension. No significant change in spinal cordblood flow was detected by either method after the applicationof spinal distraction. Nitroglycerine acts predominantly onvenous capacitance vessels and it is postulated that perfusionpressure, and therefore flow, is maintained despite a reductionin arterial pressure. Presented in part at the Anual Meeting of the American Societyof Anesthesiologists, October 1985, San Francisco, California. ^*Shackleton Department of Anaesthetics, Southampton GeneralHospital, Shirley, Southampton, Hants SO9 4XY. Section of Orthopedic Surgery, Madison, Wisconsin.     

The Effects of Magnetic Resonance Imaging on Implantable Pulse Generators

The effects of magnetic resonance imaging were assessed on four dual chamber and two single chamber pulse generators. The tests were performed with a resistive, water-cooled magnet operating at 0.15 T. The 6.4-MHz radiofrequency (RF) field was operated at a maximum power of 1,000 watts with a period adjusted from 130 to 500 ms. Reed switch closure occurred in all six pulse generators tested when placed near the entrance of the magnetic resonance imaging scanner, and the generators reverted to asynchronous operation unless programmed to the "magnet off" mode. None of the pulse generators exhibited any alterations in programmed parameters or in the ability to be reprogrammed after RF pulsing. When the RF field was turned on, there was no change in the asynchronous paced cycle length in four pulse generators; however, during RF scanning there was rapid cardiac stimulation at the RF pulse period in one single chamber and one dual chamber pulse generator.     

Care-Seeking Behavior for Newborns in Rural Zambia

Maternal and Child Health Journal - Mothers in resource-limited areas face barriers in initiating care for ill newborns, leading to delays that may contribute to newborn mortality. This qualitative...     

Orofacial evaluation of individuals with temporomandibular disorder after LED therapy associated or not of occlusal splint: a randomized double-blind controlled clinical study

Lasers in Medical Science - This study compared the effects of LED therapy associated with occlusal splint (OS) on the signs and symptoms of temporomandibular disorder (TMD). In this randomized,...     

In vitro analysis of Epstein-Barr virus: Host balance in patients with acutePlasmodium falciparum malaria

Peripheral blood lymphocytes from healthy, Epstein-Barr virus (EB-virus)-seropositive donors and from patients with acutePlasmodium falciparum malaria were tested for their cytotoxicity towards autologous EB-virus-infected B-cells using an in vitro regression assay. Of the 18 cultures from control donors, 88.8% showed the normal pattern of regression. Of the 20 malaria patients in the study, 40% failed to exhibit the normal pattern observed in the control group. Analysis of the lymphocyte subsets showed a high incidence of inverted CD4CD8 ratios in the patient group due to an absolute rise in the CD8 population. This data suggests that the immunosuppressive effects of acute malaria extend to defective control over EB-virus. The relevance of the observations to the aetiology of EB-virusassociated, endemic Burkitt's lymphoma (eBL) is discussed.