Technetium 99m-pyridoxylideneglutamate: a new hepatobiliary radiopharmaceutical. I. Experimental aspects.

The labeling of pyridoxal and the pyridoxylidene derivative of glutamic acid with 99mTc has been achieved by a simple autoclaving procedure. Technetium-99-m-pyridoxylideneglutamate (99mTc-PG) shows marked biliary excretion with accumulation of radioactivity in the gallbladder and intestines of experimental animals. This compound has been extensively investigated with a view to its application in the diagnosis of biliary disorders in man by scintigraphy. Both scintigraphic and quantitative distribution studies showed that 99mTc-PG passed rapidly through the mouse liver with progressive accumulation in the gallbladder, allowing visualization of this organ within 10 min of injection. In 30 min over 40% of the injected dose was excreted into the intestine with an equivalent amount appearing in the urine; however, renal activity remained low. Scintigraphic studies in dogs showed results similar to those obtained in mice. Studies of the toxicity in three animal species indicated a wide margin of safety for 99mTc-PG in the dose proposed for diagnostic purposes in humans.     

Vaginal colonization with group B streptococcus: a study in college women.

Vaginal specimens for culture of group B Streptococcus and anonymous questionnaires were obtained from 499 college women. Group B Streptococcus was isolated from 90 (18.0%) of the participants. A selective broth medium was more sensitive for detection of vaginal isolates (85 of 493; 17.2%) than was direct inoculation of blood agar plates (44 of 466; 9.4%). The most prevalent serotypes among the isolates were type III (37.9%) and type II (25.3%). Logit analysis identified four factors associated with a higher prevalence of vaginal colonization with group B Streptococcus. These organisms were isolated significantly more often from (1) women who had an intrauterine device (50% vs. 18.6%; P less than 0.001), (2) sexually experienced women (20% vs. 7.1%; P less than 0.02), (3) women studied during the first half of the menstrual cycle (26.5% vs. 14.5%; P less than 0.01), and (4) women 20 years of age or younger (21.4% vs. 14.8%; P less than 0.05). The prevalence of colonization with group B Streptococcus was not related to sexual practices, history of venereal disease, use of oral contraceptives, presence of gynecologic symptoms, use of antibiotics, race, educational level, marital status, or history of pregnancy.     

Occupational lead poisoning in the United States: clinical and biochemical findings related to blood lead levels

Dose-response relationships between blood lead levels and toxic effects have been evaluated in 160 lead workers in two smelters and a chemicals plant. Blood lead levels ranged from 0.77 to 13.51 mumol/litre (16-280 microgram/dl). Clinical evidence of toxic exposure was found in 70 workers (44%), including colic in 33, wrist or ankle extensor muscle weakness in 12, anaemia (Hgb less than 8.69 mumol/litre (Hb/4) or 14.0 gm/dl) in 27, elevated blood urea nitrogen (greater than or equal to 7.14 mmol/litre or 20 mg/dl) in 28, and possible encephalopathy in two. No toxicity was detected at blood lead levels below 1.93 mumol/litre (40 microgram/dl). However, 13% of workers with blood lead levels of 1.93 to 3.81 mumol/litre (40-79 microgram/dl) had extensor muscle weakness or gastrointestinal symptoms. Anaemia was found in 5% of workers with lead levels of 1.93-2.85 mumol/litre (40-59 microgram/dl), in 14% with levels of 2.90 to 3.81 mumol/litre (60-79 microgram/dl), and in 36% with levels greater than or equal to 3.86 mumol/litre (80 microgram/dl). Elevated blood urea nitrogen occurred in long-term lead workers. All but three workers with increased blood urea nitrogen had at least four years occupational lead exposure, and nine had received oral chelation; eight of this group had reduced creatinine clearance, and eight had decreased renal concentrating ability. These data support the establishment of a permissible biological limit for blood lead at a level between 1.93 and 2.90 mumol/litre (40-60 microgram/dl).