A novel method for purification of prephenic acid

Prephenic acid accumulated in culture filtrates of Neuro-spora crassa has been purified in 66% yield utilizing adsorption chromatography on Sephadex G-10 in the major purification steps.

Asphyxiating thoracic dysplasia. Clinical, radiological, and pathological information on 10 patients

Review of 10 cases of asphyxiating thoracic dysplasia has shown a wide range of clinical effects and some variability in the radiographic features. Respiratory difficulty was severe in 7 babies and lethal in 6 of these. The seventh child is remarkable for his normal stature and excellent health at 15 years of age. 3 babies had no respiratory difficulty but 2 of them subsequently died of renal failure; one remains alive at 3 years. Microscopical abnormalities in the liver and kidneys were very frequent and appeared to increase progressively with age.

Natural Water and Chemical Budgets for a Small Precambrian Lake Basin in Central Canada

Results of a 4-yr study of the hydrology of the Rawson Lake watershed, as well as the chemistry of precipitation, streamflow, and the lake are presented. Inputs of water and most chemicals varied by as much as 2 times from one year to the next, illustrating that several years’ data are necessary to determine accurately average nutrient inputs and losses from an ecosystem. Precipitation appeared to be almost the sole source of P and N to lake and terrestrial ecosystems, although N2 fixation cannot be dismissed in the latter case. Significant proportions of Ca, Mg, Na, K, Cl, and SO4 were supplied directly from precipitation. The lake also received substantial quantities of these elements as well as silicon, from weathering of terrestrial geological materials. Although far from any major industrial sources of SO2, the pH of precipitation averaged < 5 for the years studied. Both terrestrial and lake systems retained a high proportion of entering P and N, and smaller proportions of other nutrients. Interpretation of relative retentions of nutrients revealed that the terrestrial ecosystem has well-balanced P and N supplies, while the lake was P limited. Rates of loss of chemicals from the terrestrial watershed of Rawson Lake are comparable to other sites in the Precambrian Shield, but lower than values from other geological settings.

Early posterior ankle release in the treatment of congenital clubfoot

Eighty-one patients (116 clubfeet) underwent posterior ankle release before the age of two years, following unsatisfactory responses to serial corrective casts applied according to the technique of Kite. Seventy-three per cent of these feet showed no or only mild talar flattening at an average follow-up of 7.5 years. Four years, following posterior ankle release there was a none-mild talar flattening rate of 69 per cent in this group compared to a 40 per cent none-mild rate in ankle release reduces the incidence of recurrent equinus deformity and the necessity for subsequent surgery in comparison to the results obtained with serial plaster casts or with tendo Achillis lengthening alone. Recent trends in clubfoot management have favored increasingly early operative intervention. Denham stated that "In the infant hard tissues (bone and cartilage) should be regarded as soft, and the soft tissues (tendon and ligament) as hard." Our operative experience with posterior ankle release supports this philosophy and indicates that early aggressive surgical management is the treatment of choice for the resistant clubfoot.

Cerebro-hepato-renal syndrome of Zellweger. A report of eight cases with comments upon the incidence, the liver lesion, and a fault in pipecolic acid metabolism

Studies of eight patients with this syndrome confirm the characteristic pattern of abnormalities and the autosomal recessive mode of inheritance. The incidence is estimated to be approximately 1 in 100,000 live births. The liver lesion proved to be variable, with features of progressive parenchymal damage rather than a developmental defect of small bile ducts as previously suggested. Elevated levels of pipecolic acid were found in blood and urine and may be related to the basic defect.

Immunoglobulins on the surface of lymphocytes. II. The bone marrow as the main source of lymphocytes with detectable surface-bound immunoglobulin

Immunofluorescent studies using live cells from antibody-forming organs and anti-immunoglobulin antibodies demonstrate two populations of small lymphocytes which are differentiated by the presence or absence of Ig on their surface membranes. Most of the lymphocytes with detectable surface Ig appear to derive from cells of the bone marrow, while most of the Ig-negative lymphocytes derive from the thymus. Thus, adult mice thymectomized, lethally irradiated, and transplanted with bone marrow cells showed a normal number of lymphocytes with surface Ig but were depleted of the Ig-negative lymphocytes. Injection of thymocytes into these mice did not result in an increase in the number of lymphocytes with surface Ig in spleen and lymph nodes. Most of the injected thymocytes could be identified by means of histocompatibility markers. Also, the spleen and lymph nodes of neonatally thymectomized mice contained lymphocytes with surface Ig but were depleted of the Ig-negative lymphocytes. Attempts were made to identify light chains on thymocytes by a sensitive radioimmunoassay. In some experiments no light chains were detected and in others a small amount, i.e. no more than 2.6% of the amount present on spleen lymphocytes, could be detected. Whether these low figures are significant or represent a small amount of serum contamination is not clear as yet.

Free operant response reinstatement during extinction and time-contingent (DRO) reward

3 experiments are reported on the reinstatement of a bar-press response by rats during free operant extinction. After extended training on a VR schedule of food reward, an extinction procedure in which reward was negatively correlated with the bar-press response was initiated, i.e., reward was presented after 4 min of no bar presses. Results indicated that pause-contingent reward served to increase the rate of responding beyond what could be explained by the eliciting properties of reward-correlated stimuli or the “novelty” of stimulus change.