A Chinese adolescent girl with Fechtner-like syndrome

We describe a 15-y-old girl with Fechtner-like syndrome, who is the first Chinese reported to have this rare syndrome. She presented with left homonymous hemianopia and neuroimaging revealed haemorrhage in both parietal and occipital lobes. Peripheral blood smear showed macrothrombocytopenia and intracytoplasmic inclusion bodies inside leucocytes. Thrombocytopenia and proteinuria responded to intravenous immunoglobulin and pulsed methylprednisolone. This case illustrates that life-threatening haemorrhage can occur in patients with Fechtner syndrome. Although there was no effective treatment reported in the literature, high dose steroid and immunoglobulin seemed to be useful in our patient. Our patient also had nephritic-nephrotic syndrome with renal insufficiency, which is unusual in adolescent female patients.     

Genetic contributions to Parkinson's disease

Sporadic Parkinson's disease (PD) is a common neurodegenerative disorder, characterized by the loss of midbrain dopamine neurons and Lewy body inclusions. It is thought to result from a complex interaction between multiple predisposing genes and environmental influences, although these interactions are still poorly understood. Several causative genes have been identified in different families. Mutations in two genes [α-synuclein and nuclear receptor-related 1 (Nurr1)] cause the same pathology, and a third locus on chromosome 2 also causes this pathology. Other familial PD mutations have identified genes involved in the ubiquitin–proteasome system [parkin and ubiquitin C-terminal hydroxylase L1 (UCHL1)], although such cases do not produce Lewy bodies. These studies highlight critical cellular proteins and mechanisms for dopamine neuron survival as disrupted in Parkinson's disease. Understanding the genetic variations impacting on dopamine neurons may illuminate other molecular mechanisms involved. Additional candidate genes involved in dopamine cell survival, dopamine synthesis, metabolism and function, energy supply, oxidative stress, and cellular detoxification have been indicated by transgenic animal models and/or screened in human populations with differing results. Genetic variation in genes known to produce different patterns and types of neurodegeneration that may impact on the function of dopamine neurons are also reviewed. These studies suggest that environment and genetic background are likely to have a significant influence on susceptibility to Parkinson's disease. The identification of multiple genes predisposing to Parkinson's disease will assist in determining the cellular pathway/s leading to the neurodegeneration observed in this disease.     

Directly measured tissue oxygen tension and arterial oxygen tension assess tissue perfusion

Mean subcutaneous tissue PO2 (PsqO2) measurements were obtained in dogs with an unheated electrode placed in an implanted Silastic tonometer, while PaO2 was increased in increments from 40 to 600 torr during normal, increased, and reduced blood volume. These changes reflect that the mean PsqO2 is approximately 10 torr below the PO2 of venous blood draining that tissue. Since PaO2 was already known, the oxygen content of arterial and venous blood entering and leaving this tissue could be determined by reference to blood-oxygen dissociation curves. Therefore, relative changes in blood flow could be calculated using the Fick principle. After a 20% blood loss, the PsqO2 measured during breathing of room air fell to 20% of baseline, corresponding to an 80% fall in sc blood flow; it remained low until the shed blood was returned despite compensatory changes in cardiac output. Rapid infusion of electrolyte solutions in normovolemic animals produced a temporary increase in local blood flow. Subcutaneous oximetry seems capable of quantifying peripheral perfusion and may be clinically useful.     

LIMITATIONS OF RADIOTHERAPY IN THE DEFINITIVE TREATMENT OF SQUAMOUS CARCINOMA OF THE TONSILLAR FOSSA

Between 1970 and 1990, 104 patients with squamous cell carcinoma (SCC) of the tonsil were treated. The median age was 58 years and 80% of patients were males. Distribution among clinical stages was: stage I, 19 patients; stage II, 12 patients; stage III, 23 patients; and stage IV, 48 patients. More than 70% of patients had initial radiotherapy as definitive treatment irrespective of stage, reflecting the treatment philosophy over much of this period. The overall survival rate was 26% at 5 years, with survival being significantly affected by T stage, clinical stage and age. Clinical node status did not significantly affect survival rates. Good local control of T₁N₀ cancers was achieved with radiotherapy alone, but patients with more advanced cancers did poorly. We have now moved away from a non-selective policy and use initial surgery combined with postoperative radiotherapy in most patients, reserving radiotherapy alone for mainly early tonsil cancers.     

Tau isoform expression in frontotemporal dementia without tau deposition

In many cases of sporadic frontotemporal dementia (FTD) and in FTD caused by tau mutations (FTDP-17) there is disruption of the normal splicing of tau leading to the aberrant expression of tau isoforms and neurodegeneration. This suggests a central role for tau in the pathogenesis of FTD. However, more than half the cases of sporadic FTD show no tau deposition. We question whether altered expression is also involved in the pathogenesis of tau-negative FTD. Real-time polymerase chain reaction was used to investigate tau isoform expression in tau-negative FTD and age-matched controls. There were no differences in total tau mRNA or 4R versus 3R isoform expression. Our study suggests that perturbed tau mRNA expression is unlikely to be involved in the pathogenesis of tau-negative FTD.     

A comparative analysis of neurons containing catecholamine-synthesizing enzymes and neuropeptide Y in the ventrolateral medulla of rats, guinea-pigs and cats.

Neurons in the ventrolateral medulla oblongata of rats, guinea-pigs and cats that contain tyrosine hydroxylase, dopamine-beta-hydroxylase, phenylethanolamine-N-methyltransferase and neuropeptide Y have been demonstrated immunohistochemically in serial coronal sections of tissue taken from the level of the cervical spinal cord to the level of the facial nucleus. The anatomical distribution of these neurons has been described, quantified and reconstructed in three dimensions to compare the neuron populations between species. In all species, between 50 and 90% of immunoreactive neurons lay rostral to the level of the obex. There were no significant differences in the number and distribution of neurons containing catecholamine-synthesizing enzymes between control animals and those pretreated with colchicine, with two exceptions: all dopamine-beta-hydroxylase neurons were weakly immunoreactive without colchicine pretreatment in cats, and pretreatment with colchicine revealed a small rostral group of tyrosine hydroxylase-positive neurons in guinea-pigs. There were remarkable similarities in the rostrocaudal distributions of neurons containing tyrosine hydroxylase, dopamine-beta-hydroxylase and neuropeptide Y in relation to comparable anatomical landmarks across the species. However, the distributions of neurons containing tyrosine hydroxylase. Phenylethanolamine-N-methyltransferase-positive neurons, while densely stained in rats, were only faintly stained in cats and absent in guinea-pigs; the distribution of these neurons was similar to the distribution of neurons containing only tyrosine hydroxylase. The similarity of the distribution of neurons demonstrated using tyrosine hydroxylase, dopamine-beta-hydroxylase and neuropeptide Y immunohistochemistry implies that homologous catecholamine-containing neuron groups do exist in the ventrolateral medulla despite the variation in phenylethanolamine-N-methyltransferase between species. In contrast to the previous classification of neuron groups into A1 and C1 based on the presence or absence of this latter enzyme, the data suggest that a discrete group of tyrosine hydroxylase-immunoreactive neurons, which probably do not contain dopamine-beta-hydroxylase or neuropeptide Y, can be distinguished in the rostral ventrolateral medulla of all species. The absence of detectable dopamine-beta-hydroxylase in this group of neurons suggests that they may not synthesize either adrenaline or noradrenaline.