Biomedical subjects
Publications and source records attributed to R A Murray.
Ehlers-Danlos syndrome (EDS) is an inherited disorder of connective tissue with multiple thoracic manifestations. We present an unusual thoracic manifestation of EDS consisting of parenchymal cysts and fibrous and fibroosseous nodules. These manifestations may be related to an abnormal attempt at repair of parenchymal or vascular tears.
Efflux pathways for amino acids, K, and Cl activated during regulatory volume decrease (RVD) were characterized in cultured cerebellar granule neurons exposed to hyposmotic conditions. Results of this study favor diffusion pores (presumably channels) over energy-dependent transporters as the mechanisms responsible for the efflux of these osmolytes. The selectivity of osmolyte pathways activated by RVD was assessed by increasing the extracellular concentrations of cations, anions, and amino acids to such an extent that upon opening of the pathway, a permeable compound will enter the cell and block RVD by reducing the efflux of water carried by the exit of intracellular osmolytes. The cationic pathway was found selective for K (and Rb), whereas the anionic pathway was rather unselective being permeable to Cl, nitrate, iodine, benzoate, thiocyanate, and sulfate but impermeable to gluconate. Glutamate and aspartate as K but not as Na salts were permeable through the anion channel. RVD was slightly inhibited by quinidine but otherwise was insensitive to known K channel blockers. RVD was inhibited by 4,4'-diisothiocyanostilbene-2-2'-disulfonic acid (DIDS), niflumic acid, and dipyridamole. Gramicidin did not affect cell volume in isosmotic conditions but greatly accelerated RVD, suggesting that cell permeability to Cl is low in isosmotic conditions but increases markedly during RVD making K permeability the rate limit of the process. The permeability pathway for amino acids activated during RVD as permeable to short chain alpha- and beta-amino acids, but excluded glutamine and basic amino acids.
Clinicians have used the same instrument (viz, Semmes-Weinstein pressure aesthesiometers [Research Design, Inc, Houston, TX] or "von Frey hairs") for tests of both contact detection and direction discrimination. However, patients' ability to discriminate direction may be underestimated by barely detectable moving stimuli. To determine whether the aesthesiometers underestimate direction discrimination, we evaluated the capacity of 13 normal subjects to distinguish opposing directions provided by 10 different hairs. The hairs were selected to deliver forces below and above the contact-detection threshold. Each was stroked over 1.0 cm of perioral skin at the velocity at which the subject was predicted to best discriminate direction of motion. It was found that valid estimates of perioral direction discrimination can be obtained with appropriately selected aesthesiometers. Specifically, the least stiff hair whose handle displays a manufacturer's marking two units greater than that of the contact-detection "threshold hair" should be used to deliver the moving stimuli. The resultant force applied by this hair will exceed 10 times the subject's contact-detection threshold force. If a less-stiff hair is used, the capacity to distinguish direction may be underestimated.
Regulatory volume decrease (RVD) in detached cerebellar astrocytes in culture after acute exposure to hyposmolarity was characterized in this and the accompanying paper [H. Pasantes-Morales, R. A. Murray, R. Sanches-Olea, and J. Moran. Am. J. Physiol. 266 (Cell Physiol. 35): C172-C178, 1994]. RVD was independent of extracellular calcium, was accelerated at pH 8-9 and retarded at pH 6, and was reduced at temperatures < 18 degrees C. The cationic pathway activated by hyposmolarity was specific for K+ and Rb+, since RVD was abolished and secondary swelling occurred when these ions replaced Na+. However, Li+, choline, tris(hydroxymethyl)aminomethane, and glucosamine, all as Cl- salts, did not affect RVD. The anion pathway was unselective, since RVD was inhibited when NaCl was replaced by anion K+ salts with a permeability rank of SCN- = I- > NO3- > Cl- > benzoate > acetate >> SO3- > gluconate. RVD was unaffected by bumetanide (50 microM) and weakly inhibited by furosemide (2 mM). Quinidine but not other K+ channel blockers inhibited RVD, and its effect was reversed by gramicidin. RVD was inhibited by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid and dipyridamole but not by diphenylamine-2-carboxylate or anthracene-9-carboxylate. These results suggest that diffusion possibly via channels rather than cotransporters is involved in the swelling-activated K+ and Cl- fluxes. Gramicidin did not change astrocyte volume in isosmotic conditions, but greatly accelerated RVD, suggesting that low Cl- permeability in isosmotic conditions markedly increases by swelling, thus making K+ permeability the rate-limiting step for RVD.
The permeability of the hyposmolarity-activated pathway to amino acids and polyols in cultured astrocytes was examined following the change in rate and direction of regulatory volume decrease (RVD) when the extracellular concentration of the osmolytes was increased to reverse their intracellular-extracellular concentration gradient. Activation of the pathway by swelling would allow those permeable osmolytes to enter the cell and inhibit RVD. The pathway was found to be permeable to neutral amino acids, with beta-amino acids (beta-alanine = taurine > gamma-aminobutyric acid) more permeable than alpha-amino acids. Glycine, alanine, threonine, phenylalanine, and asparagine, but not glutamine, were permeable through this pathway. Aspartate was more permeable than glutamate, and K+ and not Na+ must be the accompanying cation. Basic amino acids were excluded. The dimension of the amino acid pore activated by hyposmolarity seems to be at the limit of glutamate-glutamine size. Influx rather than efflux of amino acids was observed when extracellular concentration was greater than intracellular concentration, with differences in the amount accumulated by cells correlating with their efficiency as RVD blockers. Influx of taurine (as representative of permeable amino acids) was inhibited by the Cl- channel blockers/exchangers 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (40%) and dipyridamole (85%) , and it is suggested that amino acids permeate through an anion channel. Sorbitol and mannitol, but not inositol, exhibited a small inhibitory effect on the later phase of RVD, whereas inositol slightly accelerated RVD.
To determine the incidence of physician-diagnosed Lyme disease in an endemic area of California, an active surveillance program was implemented in Lake, Mendocino, Sonoma, and southern Humboldt counties. More than 200 medical care providers were called monthly for their list of suspected cases of Lyme disease. Pertinent information was abstracted from the medical record of each patient. Of 153 cases of possible early Lyme disease ascertained from July 1991 to December 1992, 37% consisted of physician-diagnosed erythema migrans. Only 58% of erythema migrans rashes were at least 5 cm in diameter. An additional 43 patients had suspicious rashes not classified as erythema migrans. Of 166 patients with possible late-stage Lyme disease, 31% had specific clinical symptoms and 75% had a positive serologic test. With an incident case defined as physician-diagnosed erythema migrans of at least 5 cm in diameter, the annual incidence of Lyme disease in northwestern coastal California according to active surveillance only was 5.5 per 100,000. The rate of Lyme disease in California is substantially lower than that in the Atlantic northeastern United States. Many suspected cases of Lyme disease in this endemic area do not meet surveillance criteria, which are intentionally restrictive. Although some of the illnesses not meeting surveillance criteria may be due to infection with Borrelia burgdorferi, it appears that Lyme disease is being overdiagnosed in this area.
Thirty-three cases of locally acquired murine typhus were reported in Los Angeles County residents from May 1984 through February 1988. Only eight cases were reported over the previous 20-year period. Thirty (91%) cases resided within a suburban area encompassing approximately 50 km2 in northcentral Los Angeles or had contact with an animal from this area. Serologic testing (complement fixation and indirect fluorescent antibody) of selected animals in close association with human cases revealed a high prevalence of seropositivity among domestic cats and opossums. Nine (90%) of 10 resident cats tested had demonstrable antibody titers compared with none (0%) of 20 cats from a control area (P < 0.001). Suburban typhus cases were more likely than neighborhood controls to own a cat or dog (odds ratio = 6.9, 95% confidence interval = 1.8, 25.9, P = 0.002). Sixteen (42%) of 38 opossums trapped in close proximity to the residences of cases were seropositive versus none (0%) of 36 opossums from control areas (P < 0.001) A low frequency (2.8%) of seropositivity was found in commensal rodents, and the classic vector of murine typhus, Xenopsylla cheopis, was not found. Ectoparasite indices form seropositive opossums revealed heavy infestations with the cat flea, Ctenocephalides felis (mean flea count = 104.7), a species that readily bites humans. These data provide evidence that a suburban focus of murine typhus exists in Los Angeles that differs substantially from the classic transmission cycle, and that cats, opossums and C. felis may play an important role in the occurrence of human cases.
Moisturizing creams and lotions are an important aspect of preventing pressure ulcers. This study reports the increased thickening of the epithelium on 11 subjects who used a moisturizing cream (treatment) for 20 days. The thickening of the epithelium was measured before use of the moisturizing cream, on day 1, day 8, and day 20 of the treatment, and 12 days after the treatment. The ultrasound measurements were similar before the treatment and 12 days post treatment; the measurements increased for the days of treatment. Current research would lead us to believe that short-term increase in epithelial thickness as produced by a moisturizer is a result of increased water content. Ultrasound imaging may be the new standard for comparing the effects of moisturing products.
Between July 1987 and January 1988, five patients dialyzed at a hemodialysis outpatient clinic developed systemic Mycobacterium chelonae abscessus (MCA) infections. Four of the five patients had arteriovenous graft infections, and two died during antimicrobial therapy. Case-patients were more likely than control-patients to have received high-flux dialysis during the 6 mo before their infection (100% vs. 30%, P = .009). MCA was cultured from the hose connected to a water spray device used for manual reprocessing of high-flux but not regular dialyzers. Renalin was the germicide used to manually disinfect dialyzers for reuse and was prepared at a concentration of 2.5%. Laboratory studies documented survival of MCA from two high-flux dialyzers that were reprocessed in a manner similar to that used in the clinic. Early diagnosis with complete rather than partial graft removal in combination with antimicrobial therapy is recommended for MCA graft infections. In addition, 2.5% Renalin did not appear to ensure complete killing of MCA in high-flux dialyzers that were manually reprocessed at this hemodialysis clinic.
Holstein bull calves, 8 to 12 wk of age, were anesthetized with halothane gas. An approximate 20-cm section of small intestine, 60 to 90 cm proximal to the ileocecal junction was clamped to isolate blood circulation to a single set of arcuate vessels and to form an intestinal segment fitted for infusion and drainage. The vein was catheterized to allow total venous collection. Donor blood was transfused via jugular vein to replace venous drainage. This technique was evaluated in four calves by exposing the lumen to eight replications (12 or 20 min incubation, 30-min wash with 39 C saline) of 16 mM L-Met (14C-labeled). Time course appearance of Met in venous blood indicated similar rates and patterns of absorption for individual calves. There were no clinically significant alterations in jugular blood chemistry profiles across replications. Four calves were used to evaluate the effect of three isotonic perfusion media (saline, Krebs-Ringer bicarbonate and M-199 tissue culture media) on Lys and Met absorption. Venous flow rates and absorption of Lys were faster with Krebs buffer than with other media. Perfusate medium did not influence venous flow rates or absorption of Met. Effect of restricting venous flow on absorption of Lys and Met was evaluated in two calves. Flow was alternately controlled (6.5 ml/min) or allowed to flow freely (mean = 12.2 ml/min). Restricting flow decreased steady-state absorption. Light and scanning microscopy indicated maintenance of mucosal tissue integrity throughout 8 h of anesthesia. Results demonstrate validity of the in situ technique to study nutrient absorption in the young bovine.
A method is described for preparing homogenates of insects, mites, nematodes, or fungal spores for electrophoretic analysis which overcomes the disadvantages of existing methods. It is also applicable to the homogenization of microsamples of animal tissue. The method involves grinding the samples in glass tubes, closed at one end, prepared from melting-point capillaries. A range of plungers is fabricated from the stainless-steel plungers from broken microsyringes, or from stainless-steel wire. The plunger is operated by hand to homogenize a sample in 2-20 microliter of buffer in a tube. The techniques for handling the samples before and after homogenization and for labeling and centrifuging them are described. Compared with existing methods, the procedure minimizes sample loss and risk of cross-contamination and eliminates the possibility of overheating the sample during homogenization.
A review of requests for niclosamide ( Niclocide or Yomesan ) made to the Centers for Disease Control Parasitic Diseases Drug Service indicated that an outbreak of diphyllobothriasis occurred in west coast states in 1980, and in the Los Angeles area in 1981. Our investigation of 52 infections that occurred in 1980 implicates fresh salmon (Oncorhynchus spp.) as the host for the Diphyllobothrium parasite in 82% of the persons interviewed. We describe here common symptoms of the infection, methods of fish preparation employed by infected individuals, and epidemiologic data. We suggest that changes in fish marketing practices and the popularity of uncooked or slightly cooked fresh salmon were responsible for this epidemic. We recommend that salmon be either cooked or frozen before it is eaten.
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A rubella outbreak among medical staff on the obstetric service of a large Los Angeles hospital was studied. Fifteen cases of suspected rubella were reported among hospital personnel during a 2-month period in 1978. Of these, 4 were confirmed, 2 by viral isolation and serology and 2 by serologic study alone. A fifth case, the index, had a convalescent-phase serum with an elevated rubella hemagglutination inhibition (HAI) antibody titer. A list of 231 pregnant women who may have been exposed to any of the 15 suspect cases was assembled. The authors succeeded in contacting and obtaining postexposure sera for only 140 (61%) of the exposed women. Thirty-five (25%) of these women were without detectable rubella HAI antibody. A second serum sample was obtained from 93 women 2 to 3 weeks after the first, and no fourfold rises in titer were observed. To evaluate those with suspicious high stationary titers, 60 specimens were selected for immunoglobulin M (IgM) testing. Only 1 was positive for IgM antibody. A postexposure illness survey revealed that 20 (15%) of 130 women reported various rash-like illnesses after their visit to the hospital. There were no reports of affected offspring in any of the exposed women. Four hundred ten staff members submitted sera for antibody testing; 76 (19.2%) were without detectable rubella HAI antibody. This outbreak is discussed in light of recent changes in rubella epidemiology, and several recommendations for hospital policy are proposed.
In 1976, the National Institute of Allergy and Infectious Disease sponsored a nationwide network for influenza surveillance. In this paper, in addition to reporting the surveillance findings in Los Angeles, sales of nonprescription cold remedies in a large supermarket chain were evaluated as an indicator of influenza activity in the community. Twenty-seven isolates of influenza B occurred between February 17 and April 26, 1977. Peak influenza B activity occurred from mid-March to early April, 1977. A 5-10% increase in percent of respiratory and febrile respiratory illness seen in outpatient clinics was observed in late December and January. No variation in these statistics occurred during the peak of influenza activity. In contrast, sales of nonprescription cold remedies were apparently influenced by influenza B activity. Peak sales (345% increase) occurred 4 wk after the first influenza B isolate and 1 wk before peak influenza activity was documented by peak rates of isolation.
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Explore the source record for details and available documents.