Insufficiency subchondral fracture of the femoral head: report of 4 cases and review of the literature.

Insufficiency subchondral fractures are nontraumatic flattened lesions in the superolateral area of the femoral head, occurring in healthy adults. These lesions were recently described and are an infrequent cause of acute hip pain. We report on 4 patients who were diagnosed with an insufficiency subchondral fracture. All the patients showed radiographic progression of the lesion after 4 months, and 3 patients required a total hip arthroplasty. The etiology and the natural history of these rare lesions remain to be elucidated. These lesions should be differentiated from osteonecrosis and transient osteoporosis, because treatment and prognosis may differ.

Volatile organic compounds in the breath of patients with schizophrenia.

AIMS: To analyse the breath of patients with schizophrenia for the presence of abnormal volatile organic compounds. METHODS: A case comparison study was performed in two community hospitals in Staten Island, New York. Twenty five patients with schizophrenia, 26 patients with other psychiatric disorders, and 38 normal controls were studied. Alveolar breath samples were collected from all participants, and volatile organic compounds in the breath were assayed by gas chromatography with mass spectroscopy. Differences in the distribution of volatile organic compounds between the three groups were compared by computerised pattern recognition analysis. RESULTS: Forty eight different volatile organic compounds were observed in the breath samples. Three separate pattern recognition methods indicated an increased differentiation capability between the patients with schizophrenia and the other subjects. Pattern recognition category classification models using 11 of these volatile organic compounds identified the patients with schizophrenia with a sensitivity of 80.0% and a specificity of 61.9%. Volatile organic compounds in breath were not significantly affected by drug therapy, age, sex, smoking, diet, or race. CONCLUSIONS: Microanalysis of volatile organic compounds in breath combined with pattern recognition analysis of data may provide a new approach to the diagnosis and understanding of schizophrenia. The physiological basis of these findings is still speculative.

Alveolar gradient of pentane in normal human breath.

Previous studies have raised the question of whether pentane is a normal constituent of human breath, since its concentrations in inspired room air and expired breath are often similar. Using a highly sensitive assay for volatile organic compounds, we studied 37 normal subjects in order to determine the alveolar gradient of pentane in their breath (i.e. concentration in alveolar breath minus concentration in the inspired air). The chemical identity of pentane was confirmed by mass spectroscopy. The alveolar gradient of pentane was zero +/- 0.175 nmol/l in 54.1% of subjects, and distributed in an approximately bell-shaped curve. Determination of the alveolar gradient divided the normal subjects into three groups: the "passive equilibrators" who did not appear to excrete pentane in the breath (the majority), "metabolizers" who actively catabolized inhaled pentane, and "manufacturers" who excreted more pentane than they inhaled.

Effect of dietary level of protein on the activity of mouse liver calpain.

The effect of protein depletion and refeeding with a normal diet on mouse liver soluble homogenate calpain activity was studied. It was unchanged when expressed in terms of whole liver (units/liver). However, when expressed in terms of degradable protein (units/mg protein) it increased with depletion and decreased with refeeding. DEAE Sephacel chromatography of soluble homogenate yielded three calpain activities which were eluted at 0.04, 0.16 and 0.23 M NaCl, respectively. On the basis of whole liver, they decreased with depletion and increased with refeeding. Immunochemical analysis revealed similar changes in the mass of the calpain eluted with 0.16 M NaCl. The sum of these three activities (total liver calpain activity) was higher than the activity displayed by the soluble homogenate, indicating that they were separated from calpastatin. Furthermore, the percentage of total calpain activity displayed by soluble homogenate increased with depletion and decreased with refeeding, suggesting that depleted liver had the lowest calpastatin content. This was confirmed by direct measurements which indicated that depleted homogenate had in average 5.5 and 3.1 times less calpastatin compared to normal and 16 hours refed liver, respectively. It is concluded that a remarkable decrease in calpastatin content maintained unchanged whole liver soluble homogenate calpain activity during protein depletion and refeeding and contributes to an increased calpain activity related to degradable protein in depleted livers. This increase is in accordance with the high in vivo rate of protein breakdown depicted by these livers.

Increased pentane and carbon disulfide in the breath of patients with schizophrenia.

AIMS: To determine the concentrations of pentane (a marker of lipid peroxidation) and other volatile organic compounds in the breath of patients with schizophrenia. METHODS: Volatile organic compounds were assayed by gas chromatography/mass spectroscopy (GC/MS) in 88 subjects--25 with acute schizophrenic psychosis, 26 with psychiatric disorders other than schizophrenia, and 37 normal volunteers. RESULTS: The mean alveolar gradients of pentane and carbon disulfide (CS2) were significantly higher in the patients with schizophrenia than in the control groups. CONCLUSIONS: Schizophrenia may be accompanied by accelerated lipid peroxidation in cell membranes, as well as increased manufacture of CS2, a known neurotoxin.