Limitations of a thermal camera in measuring surface temperature of laser-irradiated tissues

Thermal cameras are used in research laboratories to measure tissue temperature during laser irradiation. This study was an evaluation of the accuracy of a 3-5 microns thermal camera and two 8-12 microns cameras in detecting the maximum temperatures of small targets. The size of the targets was within the range of laser spot diameters which are used for vessel welding, angioplasty, and dermatology. The response to a sharp thermal edge was measured and analyzed for the three cameras, which had a scanning rate of 30 frames per second. The response of the 3-5 microns camera to reference black body targets of different sizes was also studied. It was found that the detector system required an average of 2.44 microseconds to reach 90% of maximum step response for the 8-12 microns system and 5.85 microseconds for the 3-5 microns system. With a 3 x telescope and a 9.5 inch focal distance close-up lens, the 3-5 microns camera underestimated the temperature of targets smaller than 2.0 mm because of its slow detector response. Although the 8-12 microns camera provides more accurate measurements due to its faster detector response, it still underestimates the temperature of targets smaller than 900 microns, when similar magnification and focal distance are used. Methods to compensate for the inaccuracies are discussed, including empirical correction factors and the inverse filtering technique.     

Inhibition of voltage-gated K channels in synaptosomes by sn-1,2-dioctanoylglycerol, an activator of protein kinase C

Tracer efflux studies were used to determine the effect of activation of protein kinase C on K channel function in rat brain synaptosomes. Hippocampal synaptosomes were treated with sn-1,2-dioctanoylglycerol (diC8), a synthetic diacylglycerol (DG) analog that activates protein kinase C. DiC8 inhibited depolarization-induced 86Rb efflux through voltage-gated K channels but did not affect the component of efflux corresponding to Ca-activated K channels. In time-course experiments, diC8 inhibited two components of 86Rb efflux: efflux through a rapidly inactivating, voltage-gated K channel (responsible for the "A" current) and that through a slowly inactivating, voltage-gated K channel (believed to be the "delayed rectifier"). Experiments with specific blockers of these voltage-gated K channels supported this observation. Inhibition of K-stimulated 86Rb efflux by diC8 was time dependent: at least 15 sec of preincubation was required before the effect could be observed. The effect of diC8 was concentration dependent: 50 microM diC8 produced a half-maximal inhibition of K-stimulated 86Rb efflux. The idea that the inhibition of synaptosome K channels by diC8 resulted from activation of C kinase was supported by pharmacological evidence. The action of diC8 was mimicked by 1-oleoyl-2-acetylglycerol, another DG analog that activates protein kinase C, but not by deoxy-diC8, a DG analog that does not activate C kinase. Inhibition of C kinase by sphingosine or H-7 prevented the diC8 effect. These studies demonstrate that synaptosomes are a good model in which to study modulation of mammalian CNS K channels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical features of the exploding head syndrome.

Fifty patients suffering from the "exploding head syndrome" are described. This hitherto unreported syndrome is characterised by a sense of an explosive noise in the head usually in the twilight stage of sleep. The associated symptoms are varied, but the benign nature of the condition is emphasised and neither extensive investigation nor treatment are indicated.     

Bladder cancer and occupational exposure to polycyclic aromatic hydrocarbons

The association between occupational exposure to polycyclic aromatic hydrocarbons (PAH) and bladder cancer development was investigated in a population-based case-control study carried out in the Bormida valley, Italy. One hundred and twenty-one male cases and 342 male controls, matched age, were collected from local hospitals. Occupational exposure to PAH and aromatic amines (AA) was evaluated by means of a job exposure matrix, constructed specifically for this study. Subjects considered as sharing a "definite exposure to PAH" showed an increased risk even after adjustment for cigarette smoking and exposure to AA (OR = 2.14, 95% CL 0.82-5.60). No elevation in risk was found for the category "possible exposure to PAH" (OR = 1.05, 95% CL 0.45-2.44). The findings of this study are consistent with previous studies indicating PAH as a risk factor for bladder cancer. A possible residual confounding effect due to AA impurities is discussed.     

Reduction of nickel-induced contact hypersensitivity reactions by topical tea tree oil in humans

Objective and Design: Whilst the anti-microbial properties of tea tree oil (TTO) are established, the anti-inflammatory effects of TTO in human skin remain largely anecdotal and require evaluation. This study examined the effect of topically applied TTO on nickel-induced contact hypersensitivity reactions in human dorsal skin.Treatment: TTO (100%), a 5% TTO lotion, a placebo lotion (no TTO), or 100% macadamia oil were applied at days 3 and 5 after nickel exposure.Methods: The flare area and erythema index were measured on days 3, 5 and 7. The regulatory effects of TTO were also investigated on the proliferative response to nickel or polyclonal mitogens by peripheral blood mononuclear cells from nickel-sensitive and control subjects.Results: TTO (100%) significantly reduced the flare area and erythema index when compared to the nickel-only sites. With respect to the erythema index, the anti-inflammatory effects were predominantly, but not exclusively, seen in a subgroup of nickel-sensitive subjects with a prolonged development phase of nickel-induced contact hypersensitivity response. The 5% TTO lotion, the placebo lotion and the 100% macadamia oil were all without significant effect. TTO significantly inhibited proliferation to nickel but not to non-specific polyclonal mitogens by peripheral blood mononuclear cells from nickel-sensitive subjects.Conclusions: Topical application of 100% TTO may have therapeutic benefit in nickel-induced contact hypersensitivity in human skin. The mode of action of TTO requires further investigation, but may be an effect on the antigen presenting cells or the antigen presenting process in nickel-induced contact hypersensitivity, as well as vascular changes associated with this response.Received 14 February 2004; returned for revision 30 June 2004; accepted by J. S. Skotnicki 13 September 2004     

Comparison of two laboratory tests in the control of anticoagulant therapy

A prospective, randomized trial is described in which the usefulness of two tests in the control of anticoagulant therapy is compared. Fifty-two patients were controlled by the one-stage prothrombin time and 55 by the activated partial thromboplastin time. There was no significant difference in the incidence of bleeding between the two groups. When bleeding did occur, it was more often reflected by prolongation of the prothrombin time than of the activated partial thromboplastin time. The prothrombin time was found to have some practical advantages over the activated partial thromboplastin time.     

Nonmyeloablative bone marrow transplantation: Infectious complications in 65 recipients of HLA-identical and mismatched transplants.

Infections are a common complication of allogeneic bone marrow transplantation and the leading cause of transplantation-related mortality. It had been hypothesized that transplantation following nonmyeloablative preparative regimens would result in fewer infections by causing less mucosal injury, less graft-versus-host disease, and allowing earlier immune reconstitution. We have retrospectively reviewed the infectious complications of 65 consecutive patients with advanced hematologic malignancies who underwent bone marrow transplantation using a novel preparative regimen consisting of cyclophosphamide, thymic irradiation, and in vivo T-cell depletion. Cytomegalovirus (CMV) infection occurred in 52% of cases in which the donor or recipient had evidence of prior CMV exposure. Using a strategy of preemptive therapy and secondary prophylaxis with ganciclovir, no CMV disease occurred. Infections with gram-positive bacteria predominated over the first 100 days after bone marrow transplantation. Thereafter, the relative proportion of gram-negative infections increased without a significant increase in episodes of neutropenia. The rate of bacterial infections was not influenced by relapse of the underlying malignancy. Seven patients developed infections with Aspergillus species, which was the most common infectious cause of death in these patients. Infections with viruses other than CMV (n=10) and with protozoan organisms (n=2) also occurred. The use of HLA-mismatched donors, the occurrence of grade II-IV acute graft-versus-host disease, and treatment with corticosteroids did not influence the risk of CMV or bacterial or fungal infections in patients who underwent transplantation following this preparative regimen. Overall, the incidence and spectrum of infections in this series was similar to the reported incidence of infections following conventional myeloablative allogeneic stem cell transplantation. We conclude that a quantitative T-cell deficiency in these extensively T-cell depleted patients may be a risk factor for infection, even in the absence of graft-versus-host disease.     

A study of post traumatic stress disorder in Vietnam veterans

Three groups of Vietnam-era veterans were compared on the frequency of symptoms typical of the diagnostic criteria for Post Traumatic Stress Disorder (PTSD), a diagnostic category introduced in DSM III (N = 90). The three groups consisted of veterans who had experienced (a) a war-related traumatic event; (b) a non-war-related traumatic event; or (c) no traumatic event. The results indicated that the two groups who experienced a traumatic event reported significantly more symptoms than the group who never experienced a traumatic event. Furthermore, the group who experienced a war-related traumatic event reported more symptoms than the group who experienced a non-war-related traumatic event. These results support the validity of PTSD.     

Immunologic mechanisms in hypersensitivity pneumonitis: I. Evidence for cell-mediated immunity and complement fixation in pigeon breeders' disease

Immunologic studies were performed on 5 patients with pigeon breeders' disease. Intradermal injection of pigeon serum produced an immediate wheal-and-flare reaction within 15 minutes and a secondary Arthus-type reaction within 4 to 8 hours. Immunofluorescent studies of the secondary reaction site showed IgG, C3, and C4 in 2 patients. Patients' sera produced multiple precipitin bands with pigeon serum when reacted by double diffusion in gel. IgG antibody isolated from each of the patients' serum formed precipitating immune complexes that fixed large amounts of complement (C4) when added to fresh human serum. Peripheral blood lymphocytes from 4 of the 5 patients produced macrophage migration inhibitory factor (MIF) when challenged with dilute pigeon serum. These studies are the first to show complement fixing antibodies and macrophage MIF production by lymphocytes from patients with hypersensitivity lung disease and suggest that both humoral and cellular immunity may be important in the pathogenesis of these disorders.