Glycine conjugation of para-aminobenzoic acid (PABA): a quantitative test of liver function

N-Acetyl aspartate (NAA) is the second most abundant amino acid in the human brain. NAA is synthesized by L-aspartate N-acetyl transferase or by cleavage from N-acetyl aspartyl glutamate by N-acylated alpha-linked L-amino dipeptidase (NAALADase); and it is catabolized to acetate and aspartate by N-acetyl aspartate amino hydrolase (amino acylase II). NAA is localized primarily to neurons, where it is concentrated in the cytosol. Although NAA is devoid of neurophysiological effects, it serves as an acetyl donor, an initiator of protein synthesis or a carbon transfer source across the mitochondrial membrane. The concentration of NAA in human brain increases 3-fold between midgestation and adulthood. In Canavan's Disease, an autosomal recessive disorder due to a null mutation in amino acylase II, NAA levels in brain are markedly increased and disrupt myelination. NAA levels have been found to be reduced in neurodegenerative disorders, including Alzheimer's Disease and Huntington's Disease. Since endogenous NAA can be readily detected in human brain by magnetic resonance spectroscopy, it is increasingly being exploited as a marker for functional and structural integrity of neurons in an expanding number of disorders.     

Analysis of the structure of cardiac rhythm during treatment of auricular fibrillation with digitalis

The structure of cardiac rhythm was studied with the help of specialized computers during digitalization in 60 patients with atrial fibrillation of different etiology. The reduction of the heart contractions rate under digitalization is accompanied by certain changes in the structure of cardiac rhythm: the arrhythmic pattern of the ventricular contractions increases with a predominant growth of the number of long R--R intervals, the transitions from short intervals to longer ones become sharper, and portions of a relatively stable ventricular rhythm appear. Three main types of dynamics of the rhythm structure were distinguished on the basis of the changes in the interval R--R histogram. The described changes in the structure of cardiac rhythm are not specific, but when Digitalis drugs are used alone they can be used as additional criteria for digitalization.     

Can phenformin-induced lactic acidosis be prevented?

Although patients taking phenformin are more likely to develop lactic acidosis in the presence of renal, cardiovascular, or hepatic disease, criteria for safe use of the drug are not well established. Eight diabetics died of lactic acidosis in Nottingham in 1972-5 and all were taking phenformin in therapeutic doses. Six had attended the diabetic clinic within a month of their terminal illness. Two patients had appreciable renal impairment and should not have been given phenformin. Four had hypertension and minimal evidence of renal disease, while in two no predisposing factor was identified. There are so many contraindications to the use of phenformin that it is doubtful whether patients on the drug can be monitored adequately. We suggest that phenformin should be withdrawn from general use.     

Ultrastructural changes in the supraoptic nucleus and posterior lobe of the pituitary following experimental burns

The dynamics of the ultrastructure of the neurosecretory system in the postburn period is characterized by phasic of organells of neurosecretory cells and synapses on their bodies and processes. Immediately after burn there appear pronounced signs of an increased formation of secretion synchronous to a considerably increased functional activity of synaptic structures. Of the opposite character are fine structures in neurocytes in the subsequent period (1-1,5 hour after burn). Phenomena of disintegration and degeneration of organells are developing in the cells. In the posiologically active neurohormones and degeneration of membrane structures gradually increase at all the observed stages of the burn trauma. All the elements of the supraoptic nucleus and the posterior lobe of the hypophysis early responding to the effect of such a powerful extreme factor are involved in the response of the organism to burn. It should be noted that immediately after burn there appears an increased permeability of capillaries followed by extravasation of formed elements and liquid blood. It steadily increases with the development of the process.     

The cardiovascular effects of diazepam and of diazepam and pancuronium during fentanyl and oxygen anaesthesia

A study of the physiological behaviour of the synthetic compound Orthonil (alpha-chloro-beta-(3-chloro-o-tolyl)-propionitrile revealed a strong auxin activity in higher plants. Otherwise, Orthonil appeared not to be a herbicide-auxin. It is metabolized intensively in plant tissues. Among the identified metabolites, two compounds were detected which also exert a high auxin activity. It is concluded that at least a part of the apparent auxin activity of Orthonil may be due to alpha-(3-chloro-o-tolyl) acetic acid, one metabolite of Orthonil. Although Orthonil strongly stimulates elongation growth, this growth is not accompanied by a stimulated ethylene evolution as is the case with other auxins. A possible metabolic pathway of Orthonil is discussed.     

Beta-mercaptolactate cysteine disulphiduria in a mentally retarded Scottish male

Antenatal diagnosis of hereditary disease is highly dependent on sufficient theoretical knowledge and on a number of practical methods of studying the foetus such as obtaining, cultivating and assaying amniotic fluid cells. Knowledge of the primary defect in any monogenic disorder cannon be used in prenatal diagnosis unless the metabolic error is expressed in vitro. Modern cytogenetics can diagnose in utero a large majority of karyotyping abnormalities although the karyotype-phenotype correlation is not an absolute one. This task must be assigned to special laboratories where technical pitfalls are reliably avoided. In both metabolic and chromosomal hereditary disease, the pathologist can confirm and extend the phenotypic findings and improve knowledge on foetal features and physiopathology. Pathology is the more important, the less means of in utero diagnosis are available as in the non-chromosomal syndromes of localized or multiple malformations. Here it helps eliminating a present major drawback of prenatal diagnosis: the lack of a strict diagnosis in the previous patient in a family at risk.     

Secretion by parafollicular cells beginning at birth: ultrastructural evidence from developing canine thyroid

The ultrastructure of developing canine parafollicular cells has been examined. The hypothesis that secretion is relatively inactive prior to birth but very active at and following birth was tested. Parafollicular cells develop and accumulate characteristic secretory granules prior to birth. However, there is little or no evidence of exocytosis at this time. At birth and during the neonatal period, but not in adult thyroids, signs of exocytosis of granular contents by parafollicular cells are abundant. Just prior to the expected date of birth and before evidence of exocytosis appears, parafollicular cells accumulate intracisternal granules within rough endoplasmic reticulum. These observations are consistent with the view that parafollicular cells first become actively secretory around the time of birth and are more active at this time than in early fetal or later adult life.     

Voiding pressure as it relates to outlet and/or sphincteric resistance

Electrically quantitated and controlled detrusor contraction can produce either minimal or excessive rise in intravesical pressure depending upon openness or occlusion of the bladder outlet. Higher rise in intravesical pressure thus does not imply stronger detrusor contraction but should be viewed as a reflection of the outflow resistance mechanism. Possible damaging hydrodynamic effect of sudden partial or complete functional occlusion of the bladder outlet by intermittent or sustained voluntary sphincter activity is illustrated.