Current trends in research on the etiology and pathogenesis of byssinosis

The features of the cotton dust syndrome which need to be considered when formulating a hypothesis on mechanism(s) are: 1) the presence of fever, 2) the "Monday effect," 3) the slow onset of forced expiratory volume in 1 second (FEV1) changes, and 4) the presence of bronchitis in chronic sufferers but the absence of emphysema or fibrosis. The main hypotheses concerning the mechanisms are direct release of histamine triggered by cotton dust components, immune reactions (principally antibody mediated) to cotton dust antigens, and inflammatory response(s) triggered by endotoxins released from bacterial contaminants on the dust. While histamine release and immune reactions may occur as a result of cotton dust inhalation, it is suggested that they are of secondary importance in comparison to inflammation. Evidence is reviewed that implicates bacterial lipopolysaccharide (LPS) present in the dust as the principal etiologic agent in this process. It is postulated that LPS inhalation stimulates a secretory response by lung macrophages, involving the release of effector molecules which trigger coagulation, bronchoconstriction, fever, and mucus production. LPS-induced macrophage secretory products also promote the local sequestration and activation of both neutrophils and platelets, which serve to amplify the inflammatory response. Evidence is presented implicating both interstitial and alveolar macrophages in this process. The problems associated with the identification of "high risk" groups of cotton workers will be discussed, from a number of viewpoints; consideration will be given to the role of a variety of environmental factors (including tobacco smoking) in this context, as well as possible genetic factors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interstitial radiation therapy for hepatic metastases: sonographic guidance for applicator placement

A new technique is reported for the treatment of hepatic metastases using sonography-directed percutaneous placement of a 14-gauge needle applicator and a high-intensity "remote afterloading" iridium-192 (Ir-192) source for interstitial radiation therapy. The results with six patients show that the procedure is easily performed, patient tolerance is good, and there is minimal disruption of the patient's lifestyle. Hospitalizations have been less than 24 hr. Partial response or stable disease in the liver was observed in all six patients. Tumoricidal doses up to 5000 rad (cGy) in a single treatment with durations from 7 to 41 min were achieved in small volumes (less than 25 cm3) with no clinically significant toxicity on follow-up evaluations from 2-6 months. The technique appears to ablate discrete metastatic tumor deposits in the liver.     

Esophageal transit scintigraphy--a cautionary note

Esophageal transit scintigraphy and esophageal manometry were compared in forty-two patients with symptoms of esophageal disease. Fifteen healthy volunteers were studied as a control group for the scintigraphic investigation. Agreement between the tests was present in 79% of patients. In all the five patients in whom the esophageal manometry was abnormal and the esophageal transit study was normal, the manometric finding was "giant esophageal contractions." In four of the control group an abnormal transit pattern was observed on one of two esophageal studies. Esophageal transit scintigraphy has some limitations as a screening test for esophageal motor dysfunction.     

Milestones for autonomous in vivo microrobots in medical applications

In light of recent developments within both health care and robotics, the use of robots within the human body has become attainable. Here we discuss the milestones for the realization of autonomous microrobots in medical applications. The desired tasks were classified by identifying the difficulties and requirements faced by the robot. In addition, we classified the levels of autonomy seen in microrobots for these uses. The aim of this article is to provide readers with a good understanding of the current state and future possibilities in this field.     

Changing Levels of Social Engagement with Gay Men Is Associated with HIV Related Outcomes and Behaviors: Trends in Australian Behavioral Surveillance 1998–2020

Archives of Sexual Behavior - Changes to how gay, bisexual, and other men who have sex with men (GBM) connect with each other and with their communities have implications for HIV prevention. Social...     

A mouse model of AChR deficiency syndrome with a phenotype reflecting the human condition

The two subtypes of mammalian muscle nicotinic acetylcholine receptors (AChR) are generated by the substitution of the epsilon (adult) subunit for the gamma (fetal) subunit within the AChR pentamer. Null mutations of the adult AChR epsilon-subunit gene are the most common cause of the AChR deficiency syndrome. This is a disorder of neuromuscular transmission characterized by non-progressive fatigable muscle weakness present throughout life. In contrast with the human disorder, mice with AChR epsilon-subunit null mutations die between 10 and 14 weeks of age. We generated transgenic mice that constitutively express the human AChR gamma-subunit in an AChR epsilon-subunit 'knock-out' background. These mice, in which neuromuscular transmission is mediated by fetal AChR, live well into adult life but show striking similarities to human AChR deficiency syndrome. They display fatigable muscle weakness, reduced miniature endplate potentials and endplate potentials, reduced motor endplate AChR number and altered endplate morphology. Our results illustrate how species differences in the control of ion-channel gene expression may affect disease phenotype, demonstrate that expression of adult AChR subtype is not essential for long-term survival, and suggest that in patients with AChR deficiency syndrome, up-regulation of the gamma-subunit could be a beneficial therapeutic strategy.     

Intravenous pulsed steroids in rheumatoid arthritis: a comparative dose study

This prospective, double blind study was undertaken to test the efficacy of intravenous "minipulse" (100 mg) methylprednisolone (MP) therapy versus standard pulse (1000 mg) MP therapy in rheumatoid arthritis (RA). Thirty-six patients with RA synovitis flares were randomized to receive either 100 or 1000 mg MP IV QD x 3 doses. These 2 universally comparable groups exhibited no statistically significant differences in their striking prompt and sustained clinical improvement. These data suggest that minipulse MP is as efficacious as conventional pulse MP in the treatment of RA flares.