PubMed HealthSearch

Biomedical subjects

M Lara

Publications and source records attributed to M Lara.

At least 19 recordsLinked to original sources

Hypersomnia after tegmental pontine hematoma: case report.

We describe polysomnographic studies of a 44 years-old man who showed a defect in the central nervous regulation of the sleep-waking cycle (SWC), hypoventilation and cardiovascular hyperactivity after a right-sided tegmental pontine hematoma. A significant increase in total sleep time mainly depending upon stage 1 + 2 was observed. Predominant unilateral damage to the medial and central region of the reticularis pontis oralis (Poo) nucleus, extending into the central part of the rostral reticularis pontis caudalis (Poc) nucleus, was presumably responsible for the hypersomnia in this patient.

Adult

Type I familial amyloid polyneuropathy and pontine haemorrhage.

A Portuguese female, aged 47 years, who had emigrated to Spain, was admitted to the hospital in 1991 for pontine haematoma. The patient, four siblings and her father were affected by a peripheral neuropathy, indicating autosomal dominant inheritance. The patient presented in the 2nd decade with sensory and motor neuropathy beginning in the lower extremities. Alternating constipation and diarrhoea, and urinary incontinence became uncontrollable. She had to be colostomised, and, eventually, confined to a wheelchair from the age of 43. Neurological examination showed bilateral facial involvement, and severe signs of sensory and motor peripheral neuropathy, and later right hemiplegia. There were abnormalities of atrial rhythm and left bundle branch block. Computerised axial tomography and magnetic resonance images demonstrated left-sided pontine haemorrhage. Nerve conduction studies revealed severe diminution of motor conduction velocity and absence or reduction of amplitude of sensory and motor action potentials. Inanition and a respiratory infection led to her death. Clinical diagnosis was type I familial amyloid polyneuropathy (FAP). Postmortem examination demonstrated amyloid deposits in peripheral nerves, including spinal roots and cranial nerves, leptomeninges, thyroid, breasts, heart, adrenal glands, kidneys, intestines, pancreas, and meningeal and some pontine vascular structures. Advanced pontine haematoma was verified. Cerebral haemorrhage usually occurs with cerebrovascular amyloidosis, but exceptionally with FAP. A minority of patients presenting with CNS haemorrhage showed arteriovenous malformation or embolism [Da Silva Horta and Dias Coelho (1960) Arch 'de Vecchi' Anal Patol Med Clin 31 = 163-172].(ABSTRACT TRUNCATED AT 250 WORDS)

Amyloid

Modulation of rat liver peroxisomal and microsomal fatty acid oxidation by starvation.

In this work the microsomal lauric acid omega-hydroxylation, fatty acid peroxisomal beta-oxidation, and the levels of cytochrome P-450 IVA1 were studied in liver tissue from starved rats. Starvation increased the peroxisomal beta-oxidation and the microsomal hydroxylation of fatty acids. The correlation between these activities would support the proposal that both processes are linked, contributing in part to catabolism of fatty acids in liver of starved rats.

Animals

The Rhizobium leguminosarum biovar phaseoli glnT gene, encoding glutamine synthetase III.

Plasmid pGE203 contains the Rhizobium leguminosarum biovar phaseoli glnT locus. Glutamine synthetase III (GSIII) was purified from a glutamine auxotrophic strain of Klebsiella pneumoniae carrying this plasmid. Sequencing of a 2.4-kb fragment containing the glnT locus reveals an open reading frame of 435 amino acids (aa), whose first eight aa are identical to those determined from pure GSIII by direct aa sequencing, thus confirming that glnT indeed codes for GSIII activity. The comparison of the GSIII aa sequence with the reported sequence of GSs from other organisms shows a significant degree of homology. Since the three-dimensional structure of GS from Salmonella typhimurium is known, a three-dimensional model of GSIII was built by homology.

Amino Acid Sequence

Long-term undiagnosed syphilis with clinical presentation of meningitis.

A 43-year-old woman, with an 11-year history of progressive cutaneous lesions, was considered to have granuloma annulare and was treated as such for 4 years. She then developed chronic meningitis. Serological investigation revealed active syphilis. Appropriate antibiotic treatment led to a rapid resolution of the clinical symptoms. The recent reports of similar cases indicate the importance of an adequate knowledge of clinical manifestations and pathological patterns of syphilis.

Adult

Intramedullary spinal cord abscess.

We report a patient with a chronic intramedullary spinal cord abscess who suffered an episode of acute meningitis due to rupture of the abscess into the subarachnoid space.

Abscess

[Peripheral neuropathy in HIV infection].

Neuropathy may complicate all stages of human immunodeficiency virus infection (HIV). Different types of peripheral neuropathy and myelopathy have been reported associated with HIV infection: sensory symmetrical polyneuropathy, acute inflammatory demyelinating polyneuropathy, chronic inflammatory demyelinating polyneuropathy, mononeuropathy multiplex, sensory ataxic neuropathy (ganglioneuronitis), cauda equina syndrome, amyotrophic lateral sclerosis, spastic paraparesia, and subclinical neuropathy diagnosed by electrophysiologic study. We describe the main clinical, electrophysiological and pathological features in these different types of neuropathy and comment their pathogenesis and treatment. Results in our series of twenty-two patients are also reported. In this series we want to underline three cases in which a chronic demyelinating polyneuropathy was the first manifestation of HIV infection. Thus, patients with predominantly motor demyelinating neuropathies and suspicious risk factors should be screened for silent HIV infection.

Acquired Immunodeficiency Syndrome

Physiology of ammonium assimilation in Neurospora crassa.

In Neurospora crassa the assimilation of high and low concentrations of ammonium occurs by two different pathways. When the fungi are growing exponentially on ammonium excess, this compound is fixed by a glutamic dehydrogenase and an octameric glutamine synthetase (GS). The synthesis of this GS polypeptide (beta) is regulated by the nitrogen source present in excess; being higher on glutamate, intermediate on ammonium, and lower on glutamine. When N. crassa is growing in fed-batch ammonium-limited cultures a different polypeptide of GS (alpha), arranged as a tetramer, is synthesized. In both conditions synthesis in vivo correlates with the data obtained with an in vitro translation system primed with N. crassa RNA. This different expression of alpha and beta GS polypeptides was also observed when the cultures were shifted from excess to low nitrogen, and vice versa. By agarose gel electrophoresis in the presence of methylmercury hydroxide, some separation of different mRNAs that direct the in vitro synthesis of alpha and beta GS polypeptides has been accomplished. Data are presented that establish the operation of the tetrameric alpha GS and of glutamate synthase in the assimilation of ammonium in low concentration.

Ammonium Chloride