Joseph L. Potter

The neuropathology of glycine encephalopathy A report of five cases with immunohistochemical and ultrastructural observations

We studied the spongy myelinopathy of glycine encephalopathy in five patients by using specific antisera. The walls of the vacuoles were stained with the myelin basic protein but not with the myelin associated glycoprotein or the glial fibrillary acidic protein immunostains. The pattern suggested that the vacuoles originated in compact myelin and not from the adaxonal portion of the sheath or from glial processes. Ultrastructural study revealed myelin vacuoles resulting from intraperiod splitting, and there were unusual intranuclear and cytoplasmic inclusions in skeletal muscle in two cases. In addition to the action of glycine as an inhibitory neurotransmitter, structural alterations of myelin may be important in the pathogenesis of the neurologic disorder of glycine encephalopathy.

Lipoprotein disorder, cirrhosis, and olivopontocerebellar degeneration in two siblings

Two siblings had olivopontocerebellar degeneration, failure to thrive, hepatic fatty change and cirrhosis, and a dyslipoproteinemia characterized by low cholesterol and elevated triglycerides. This condition was distinct from other cerebellar atrophies and ataxias and was not due to malabsorption or malnutrition. Cerebellar degeneration progressed rapidly during the first year of life, and both children died from intercurrent infections and surgical complications at 11 and 17 months. Stereotyped clinical and pathologic findings in the two patients suggest a previously unreported genetic metabolic disorder affecting the liver and the CNS.

Methemoglobinemia due to ingestion of N,N-dimethyl-p-toluidine, a component used in the fabrication of artificial fingernails

An acute cyanotic episode due to methemoglobinemia occurred in a 16-month old girl following the ingestion of N,N-dimethyl-p-toluidine, a commercially available component used in the production of artificial fingernails. The amount of the parent compound ingested was about 6 mg/kg of body weight. Administration of methylene blue was effective in the reversal of the methemoglobinemia. In vitro studies suggest that the activity of the compound was probably due to its biochemical transformation to the toxic metabolite p-methylphenylhydroxylamine. We expand the list of aromatic amino or nitro compounds and their derivatives capable of producing methemoglobinemia and call attention to the hazard of their ingestion.

Benzocaine-induced methemoglobinemia

Intense cyanosis in a previously well, 30-month-old, white girl was found to be due to the ingestion of benzocaine. A wide variety of chemical compounds present in many proprietary products, when ingested, can cause this presentation in individuals with structurally normal hemoglobin and normal activity of methemoglobin reductase. The phenomenon appears to be dose-related. Immediate recognition and initiation of appropriate therapy will effect a rapid reversal of the methemoglobinemia, and in some cases, may be life-saving. Caution should be exercised in the use of benzocaine-containing preparations.

Neonatal glycine encephalopathy: Biochemical and neuropathologic findings

A patient with neonatal glycine encephalopathy who had severe neurologic retardation, spasticity, and seizures died at 17 years of age. Glycine concentration was markedly elevated in brain tissue, especially in the cerebellum. Neuropathologic study revealed spongy myelinopathy throughout the central nervous system and calcium oxalate crystals in the cerebellum, which are probably derived from degradation of glycine. Myelinopathy appeared to be static compared to neonatal patients. The neurologic manifestations of neonatal glycine encephalopathy are probably due to neurotransmitter abnormalities, not to myelin damage.

Acute zinc chloride ingestion in a young child

This brief report describes the clinical course and management of a child who ingested a zinc chloride solution used in a lead soldering process. Injury was limited to bleeding from esophageal erosions and hematemesis. No adverse systemic effects were observed, although serum zinc levels were markedly elevated. A single small dosage of calcium disodium edetate (150 mg dissolved in 75 ml 1:5 normal saline) was effective in normalizing the serum zinc level.

An improved method for the determination of leukocyte arylsulfatase A and its application to the diagnosis of metachromatic leukodystrophy in homozygous and heterozygous states.

Abstract An improved method for the determination of arylsulfatase A, based on the ether solubility of 4-nitrocatechol, has been established. The method has been applied to the diagnosis of metachromatic leukodystrophy and can identify the carrier state. The method is also useful in organ surveys for the enzyme.

Massive Hyperlipidemia in Diabetic Ketoacidosis The Clinical Importance of Laboratory Recognition

An eight-year-old girl was entirely well until ten weeks prior to admission when she became easily fatigued and unusually irritable. During the three weeks prior to admission, she lost seven pounds, and had the classic triad of polyphagia, polydipsia, and polyuria. On the day of admission, a croupy cough with stridor developed. She appeared acutely ill and dehydrated, but was ambulatory and alert. Urinalysis revealed 4+ glucosuria and 4+ ketonuria. Admission studies

Radiocontrast interference in screening tests for genetic-metabolic diseases.

Screening tests for genetic metabolic diseases remain extremely useful due to their rapidity, ease of interpretation and substantial reduction of cost. However, interferences in these tests are still a source of concern in laboratory medicine. Cost considerations have so compressed the duration of the medical work-up that the administration of radiologic contrast may often antedate the collection of body fluids for genetic-metabolic testing. It has been found that under these circumstances, certain contrast media may interfere with the urinary studies of amino acids, organic acids, and tests involving ultraviolet absorption such as those concerned with purines, pyrimidines, and related compounds. The consequences of interference may be misdiagnosis, repeated testing, extensive and expensive work-ups, and unnecessary delay and anxiety for the family. As in all testing, it is prudent to avoid medications and atypical diets, if possible. In the case of contrast media, it is a simple matter to collect samples for analysis prior to the administration of radiocontrast so as to avoid the pitfalls and yet not delay the diagnostic work-up.

Occult hepatic sinusoid tumor of infancy simulating neuroblastoma

Two infants with hepatosplenomegaly and an occult tumor of hepatic sinusoids are reported. Although secretion of biogenic amines of neuroblastoma was not elevated, infrequent neurosecretory granules were observed by electron microscopy in the cytoplasmic processes of the tumor cells. The infants responded to vincristine and prednisone therapy and are tumor free 8 and 2 years later, respectively. The clinical, radiographic, biochemical, and microscopic findings of these cases are presented. The distinction from other infantile hepatic sinusoid small round cell tumors is based on the light and electron microscopic findings. This neuroepithelial tumor is either an unusual form of neuroblastoma or a neoplasm of APUD cell origin. If chemotherapy is utilized, it should be selective and limited.