Mitochondrial DNA variation in maize plants regenerated during tissue culture selection.

Plants resistant to Helminthosporium maydis race T were obtained following selection for H. maydis pathotoxin resistance in tissue cultures of susceptible, Texas male-sterile (T) cytoplasm maize. The selected lines transmitted H.

Addicted physicians. A closer look.

Fifty physicians were evaluated and treated in a psychiatrically oriented, short-term addiction program. Psychopathology ranged from overt schizophrenia to no demonstrable psychiatric syndrome other than the addiction. Physicians experiencing addiction problems before age 40 years were more likely to exhibit serious psychopathology in the borderline range, while physicians older than 40 years were more likely to exhibit organic brain impairment and depression.

Genetic screening of newborn in Australia: results for 1979.

Since screening of newborn infants for phenylketonuria (PKU) by Guthrie bacterial inhibition assay was established in the 1960s, 2 556 498 infants have been tested in Australia. Two hundred and twenty-two cases of PKU, and five cases of the variant forms of malignant hyperphenylalaninaemia (MHPA) have been found over this period, an incidence of 1/11 516 for PKU, and 1/511 300 for MHPA. In 1979, 18 infants with PKU and one with MHPA were detected.

Disruption of drug-dependent learning (memory retrieval) using an ethanol drug state: a replication.

Eight groups (n = 8 per group) of rats were trained to escape foot shock by turning in the correct direction in a T-maze and 24 h after reaching criterion all groups were tested with no foot shock. The four experimental groups were given alternating drug and nondrug test days while the four control groups always experienced the same drug state in training and in testing. Two experimental groups (transfer) heard a 1 kHz tone that was simultaneously paired with foot shock during training, and the tone continued to be sounded on all test trials.

Genetic screening of the newborn in Australia. Results for 1978.

Since screening of newborn infants for phenylketonuria (PKU) by Guthrie bacterial inhibition assay was established in the 1960s. 2 334 679 infants have been tested in Australia, and 208 cases of PKU detected (an incidence of 1/11 224). In 1978, 21 infants with PKU were detected.

Isolation and characterization of two homoserine dehydrogenases from maize suspension cultures.

Homoserine dehydrogenase in unpurified extracts of maize (Zea mays L.) cell suspensions is inhibited 73% by the feedback regulator threonine; the remaining 27% of the total activity is not affected even by high concentrations of threonine. The threonine-resistant and threonine-sensitive homoserine dehydrogenase activities were separated by affinity chromatography on Blue Sepharose columns, and the two distinct homoserine dehydrogenases were purified.

Alcohol problems in several midwestern homosexual communities.

According to their scores on the Michigan Alcoholism Screening Test, close to one-third of the homosexual men surveyed in four urban areas of Kansas were alcoholics.

Contagiousness of acute hepatitis B. Secondary attack rates in household contacts.

In order to define the hazard of household exposure to patients with acute hepatitis B, in the absence of persistent hepatitis B surface antigen (HBSAg), 98 household contacts of 42 patients with the acute disease were interviewed and tested for HBSAg, antibody to HBSAg (anti-HBS), and serum transaminases shortly after identification and at 3-month intervals for at least 12 months. Most of the index cases with acute hepatitis B were young men and many had used illicit drugs parenterally before the onset of illness. Three of the household contacts had HBSAg detected on initial testing, and 2 of these were carriers with elevated serum transaminase levels.

Effect of foot-shock intensity on amount of memory retrieval in rats by emotionally important stimuli in a drug-dependent learning escape design.

Drug-dependent learning (lack of transfer between drug states) was demonstrated and disrupted in an escape learning, forced choice T-maze task. A drug-dependent learning (DDL) group was trained to escape foot shock (0.65 mA) while in a drug (chlordiazepoxide hydrochloride) state.

Hypothalamic hypopituitarism following external radiotherapy for tumours distant from the adenohypophysis.

Three cases of panhypopituitarism and five of isolated growth hormone deficiency which occurred following previous external irradiation of tumours distant from the adenohypophysis are described. The hypothalamic pituitary region received between 2800 and 12 000 rads in each case, 1-9 years before endocrine deficiency was recognized. Evidence is presented that the site of damage is in the region of the hypothalamus rather than the pituitary gland itself.

Elastin fibers in scar tissue.

Scar tissue, obtained from humans, was stained for elastin fibers by a new staining method. Elastin fibers were noted at sites where they must have been formed de novo. The morphology and the distribution of elastin in various types of scars are described.

Disruption of state-dependent learning (memory retrieval) by emotionally-important stimuli.

State-Dependent Learning (SDL) occurs when a response learned in a particular drug stste does not transfer to another drug state. SDL was demonstrated and disrupted in a modified T-maxe escape learning task, using male hooded rats. SDL groups were trained each day in one drug state (either Librium, 40 mg/kg or sterile water) and then given non-shock test trials in both drug states.