Retine revisited.

Retine, so named by Albert Szent-Györgyi, an inhibitor of the growth of transplanted malignant tumours in animals, is present in all mammalian tissues and in urine. Its inhibitory activity was extensively investigated by Szent-Györgyi, but its exact chemical identity was not determined. Details of the reported physical and chemical properties of retine and its ubiquitous occurrence identify it as being identical to a complex mixture of lipid 2,4-diketones of similar ubiquitous occurrence. This lipid mixture has been extensively studied, and individual members have been synthesized.

Use of miniature biplane transesophageal echocardiography during pediatric atrial catheter interventional procedures.

We reported the use of a new miniature biplane TEE probe during pediatric cardiac interventional catheterization procedures. Use of this imaging modality provided significant advantages during dilation of obstructed venous pathways and closure of interatrial defects. Procedural characteristics and specific congenital heart lesion-related advantages were discussed.

Successful radiofrequency catheter ablation of atrial muscle reentry tachycardia in a young adult.

Atrial muscle reentry as a mechanism of tachycardia has been well illustrated in isolated animal atrial muscle. It has infrequently been reported as an etiology of supraventricular tachycardia in young patients. A case of atrial muscle reentry tachycardia and its successful elimination using radiofrequency catheter ablation is reported.

Higher aliphatic 2,4-diketones: a ubiquitous lipid class with chelating properties, in search of a physiological function.

A group of homologous 2,4-diketones with chain lengths from C13 to C25, derived from fatty acids, is present in human and mammalian tissues and urine. The presence of this lipid class, members of which possess marked chelating properties, adequately accounts for the well-documented antiallergic activity of tissue and urine extracts on isolated smooth muscle preparations and in guinea pigs in vivo. This review summarizes the investigations leading to the discovery of this lipid class. It is postulated that the observed antiallergic activity of 2,4-diketones may be explained by the intracellular sequestration of calcium ions transiently liberated from intracellular storage pools after an agonist-receptor interaction, thus blocking response to the agonist. The true physiological function (or functions) of this lipid class has not been defined. The chelating properties of 2,4-diketones suggest their involvement in intracellular ionic interactions.

Management of impacted anterior teeth utilizing basic orthodontic principles.

Treatment of the impacted anterior tooth can be achieved using the appropriate surgical and orthodontic methods. A thorough examination must be completed to determine the intervention required.

Cannabis affects the severity of schizophrenic symptoms: results of a clinical survey.

Data on the history of cannabis use and a spot urine test for cannabinoids were obtained for 137 schizophrenics in treatment. Subjects who were using cannabis during the 6-month observation period presented with a significantly higher degree of delusional and hallucinatory activity than those who did not. Moreover, the group using cannabis made a higher average number of visits to the hospital during the same period. The status of cannabis use appeared to contribute to such variance more than did other relevant factors (age, stage of the illness, amount of medication prescribed, occasional use of other psychoactive substances).

The qualitative analysis of renal calculi with the polarising microscope.

The crystallographic method of Prien and Frondel for the qualitative analysis of renal calculi has been employed for seventeen years. The method was supplemented by occasional chemical tests. Advantages of the crystallographic method over other procedures are the ability to identify specific minerals even in trace amounts, the capability to analyse very small stones, and the rapidity with which analyses can be performed. Data are presented for 1653 calculi.

The isolation and identification of 2,4-diketones present in human and animal tissues and in urine.

The chemical isolation of 2,3-diketone fraction from hydrolysates of various mammalian tissues has been accomplished by the use of a modified Girard T procedure. This fraction, which constitutes a new lipid class, has been resolved by gas chromatography into a number of homologous 2,4-diketones, ranging in chain length from C13 to C25. After separation by preparative gas chromatography, the following compounds have been unequivocally identified: 2,4-heptadecanedione, 2,4-nonadecanedione, 2,4-heneicosanedione, 2,4-docosanedione, and delta12-2,4-heneicosenedione. The 2,4-diketones appear to exist in tissues in the free state or in labile combination. They are present also in human urine.

The preparation, gas liquid chromatography, and some physical and chemical properties of certain higher aliphatic 2,4-diketones--a new lipid class.

Fourteen saturated aliphatic 2,4-diketones, ranging in chain length from C7 to C25, and one unsaturated compound, delta12-2,4-heneicosenedione, were prepared by Claisen acylations of the appropriate methyl ketones, and their gas chromatographic behavior was studied. Mixtures of these diketones were resolved on columns containing UCW98 or Carbowax 20M stationary phases. Their methoxime and 2,4-dinitrophenylsemicarbazone derivatives were resolved on OV-17 and OV-1 stationary phases, respectively. Since higher homologous aliphatic 2,4-diketones have been found in mammalian tissues, they constitute a new lipid class.

Some observations on the antihistamine activity in the guinea pig of aliphatic 2,4-diketones, a new class of physiological tissue components.

Eight saturated aliphatic 2,4-diketones, ranging in chain length from C7 to C21 were examined for their potency in counteracting the effects of histamine anaphylaxis in guinea pigs. A 0.2% suspension of the mixed C15, C17, C19 and C21 diketones was more effective than a 1% phenylephrine solution when these were administered as aerosols. Of the individual diketones, 2,4-nonadecanedione was the most potent in vivo. ED50 data for the antihistamine activity of the C7, C9, and C13 homologues in the in vitro guinea pig ileum bioassay indicated that, on a weight basis, the activity increased with increasing molecular weight. The antiallergic activity of tissue and of urine extracts has been attributed to the presence of 2,4-diketones.

Ethchlorvynol (Placidyl) intoxication and its treatment by hemodialysis.

Twenty hours after ingesting 15-25 g. of ethchlorvynol, a 37-year-old woman was admitted comatose and in shock. The blood level of ethchlorvynol was 21.6 mg. % (method of Wallace). Supportive measures were instituted and hemodialysis, carried out for 10 hours, removed 5.49 g. of the drug. The post-dialysis blood level was 9.05 mg. % and the rate of dialysance was 50.5 ml./min. Only 0.6 g. of the substance was recovered from the urine over the same period.Although dialysis removed significant amounts of the drug and sustained life, the patient remained comatose for five days before withdrawal symptoms and seizures developed.