The effect of emotional-painful stress, hypoxia, and adaptation to it on the activity of enzymes for metabolizing glutathione and concentration of glutathione in rat organs

The stress activates glutathione peroxidase in the heart, liver, and kidney, glutathione transferase in the heart and liver, inhibits gamma-glutamyl transferase in the liver; the activity of glutathione reductase and the content of reduced glutathione were unchanged. Two-four-minute hypercapnic hypoxia unchanged the activity of glutathione metabolic enzymes. The activity of the above enzymes decreases in some organs at the death caused by 2-15-minute hypoxia. Long-term intermittent adaptation to hypobaric hypoxia lowers the activity of glutathione peroxidase, -transferase and -reductase. The biological value of the two types of enzymatic responses may be different: stress-induced activation of glutathione metabolic enzymes can enhance resistance to stress and xenobiotics; however, their inhibition during hypoxic adaptation may produce the opposite effect.     

Evaluation of the treatment of malaria using a 3-day regimen of quinine in Dakar

The paper provides a brief account and technical data of an AP-94-type device (a refractometer) for examination of ocular refraction, which operates in the infrared spectrum and allows a correct diagnosis to be promptly and qualitatively established and corrective means to be chosen for the patient. The results of clinical tests of the device are given.     

A preliminary investigation of high-school counseling resources on the Cape Peninsula

In South Africa, counseling and guidance services remain marginalized. The aim of this study was to determine the structure and function of the counseling facilities in high schools on the Cape Peninsula. The first telephone survey comprising 68 representatively and randomly selected schools revealed that 26% of schools had no guidance department, and the mean full-time guidance teacher-pupil ratio was 1:897. The second survey involving 33 randomly selected full-time and part-time guidance teachers from the first sample showed that they could assign on average 14.4 minutes of counselling per pupil in one school year. Analysis of the full-time guidance teachers (N = 22) time allocation revealed that 23% of time was allocated to counseling, 32% to guidance, and 45% to formal teaching and administration. These results suggest that the allocation of personnel and time to counselling are deficient. An implication is that adolescents with psychological problems go undetected and therefore untreated.     

The control of microvascular permeability and blood pressure by neutral endopeptidase

Plasma extravasation from postcapillary venules is one of the earliest steps of inflammation. Substance P (SP) and bradykinin (BK) mediate extravasation and cause hypotension. The cell-surface enzyme neutral endopeptidase (NEP) inactivates both peptides. Thus, absence of NEP may predispose development of inflammation and hypotension. We examined these possibilities in mice in which the NEP gene was deleted by homologous recombination. There was widespread basal plasma extravasation in postcapillary venular endothelia in NEP-/- mice, which was reversed by recombinant NEP and antagonists of SP (NK1) and BK (B2) receptors. Mean arterial blood pressure was 20% lower in NEP-/- animals, but this was unaffected by reintroduction of recombinant NEP and the kinin receptor antagonists. The hypotension was also independent of nitric oxide (NO), because NEP-/- mice treated with a NO synthase inhibitor remained hypotensive relative to the wild type. Thus, NEP has important roles in regulating basal microvascular permeability by degrading SP and BK, and may regulate blood pressure set point through a mechanism that is independent of SP, BK and NO. The use of NEP antagonists as candidate drugs in cardiovascular disease is suggested by the blood pressure data reported herein.     

Unilateral retinoblastoma: new intraocular tumours after treatment

A retrospective chart review of 427 eyes diagnosed with unilateral retinoblastoma was performed to determine which eyes, which patients, and when new intraocular tumours would develop after treatment. Mean follow up was 8.16 years. Twenty five (6%) of 427 unilateral retinoblastoma patients developed new intraocular tumours after treatment. Five (1%) unilateral patients who were previously treated with enucleation developed new tumours (in the fellow eye). Fifteen (24%) unilateral patients who were previously treated with external beam radiation developed new tumours (equally in either eye). New tumours did not develop in the macula of either eye. The relative risk of developing new intraocular tumours after treatment was 16% in patients diagnosed before 1 year old and 2.2% for patients diagnosed after 1 year old (p < 0.001). The mean time to onset for the development of new tumours after treatment was 0.74 years; no new tumours appeared after 7.5 years of age. Those patients who are diagnosed with unilateral retinoblastoma in the first 6 months of life and have a family history of the disease are at greatest risk of developing new intraocular tumours.     

Psychologists in the eyewitness world

Over the past century, but especially over the past 20 years, psychological studies of eyewitness identification have been accumulating. Wells (1993, this issue) believes that the time is ripe to summarize the research on identification procedures, such as lineups and showups, that will minimize false identifications of innocent people and maximize accurate identifications of the guilty. Other experts in the field worry that there is still too big a leap from the laboratory work to the real world of crime. Identification research, many agree, has the potential for being one of the more useful arenas in which psychological science can make a difference in society.     

Macrophage-derived nitric oxide induces apoptosis of rat hepatoma cells in vivo

Although nitric oxide (NO) has been postulated to play important roles in host defense mechanisms against tumor cells, a direct evidence supporting this hypothesis is lacking. To obtain molecular insights into the antitumor action of NO, its metabolism and effect on ascites hepatoma (AH-130) cells were investigated in tumor-bearing rats. Kinetic analysis revealed that substantial amounts of nitrite and nitrate, metabolites of NO, appeared in plasma and ascites of AH-130-inoculated rats. Western blot analysis revealed that a large number of macrophages that expressed inducible type of NO synthase (iNOS) appeared in cancerous ascites, particularly during 1 to 2 weeks after inoculation of AH-130 cells. When NO generation by peritoneal macrophages increased, a significant fraction of AH-130 in ascites fluid underwent apoptosis as judged from the fragmentation of their nuclear DNA. Kinetic analysis revealed that NO strongly inhibited mitochondrial electron transport and changed calcium status in AH-130 cells, particularly under low oxygen tensions such as in cancerous ascites. Intraperitoneal injection of NO donor strongly enhanced DNA fragmentation of AH-130 cells. Antimycin A, a specific inhibitor for mitochondrial electron transport, also induced DNA fragmentation of AH-130 cells by a mechanism that was inhibited by adding ascorbate and tetramethyl-p-phenylene diamine (TMPD) as electron donors. These results indicate that NO derived from peritoneal macrophages inhibits mitochondrial electron transport and disturbs calcium homeostasis in ascites hepatoma AH-130 cells, thereby inducing their apoptosis in vivo.