Cerebral gliomas: prospective comparison of multivoxel 2D chemical-shift imaging proton MR spectroscopy,echoplanar perfusion and diffusion-weighted MRI

Developments in MRI have made it possible to use diffusion-weighted MRI, perfusion MRI and proton MR spectroscopy (MRS) to study lesions in the brain. We evaluated whether these techniques provide useful, complementary information for grading gliomas, in comparison with conventional MRI. We studied 17 patients with histologically verified gliomas, adding multivoxel proton MRS, echoplanar diffusion and perfusion MRI the a routine MRI examination. The maximum relative cerebral blood volume (CBV), minimum apparent diffusion coefficient (ADC) and metabolic peak area ratios in proton MRS were calculated in solid parts of tumours on the same slice from each imaging data set. The mean minimum ADC of the 13 high-grade gliomas (0.92+/-0.27 x 10(-3) mm(2)/s) was lower than that of the four low-grade gliomas (1.28+/-0.15 x 10(-3) mm(2)/s) ( P<0.05). Means of maximum choline (Cho)/N-acetylaspartate (NAA), Cho/creatine (Cr), Cho/Cr in normal brain (Cr-n) and minimum NAA/Cr ratios were 5.90+/-2.62, 4.73+/-2.22, 2.66+/-0.68 and 0.40+/-0.06, respectively, in the high-grade gliomas, and 1.65+/-1.37, 1.84+/-1.20, 1.61+/-1.29 and 1.65+/-1.61, respectively, in the low-grade gliomas. Significant differences were found on spectroscopy between the high- and low-grade gliomas ( P<0.05). Mean maximum relative CBV in the high-grade gliomas (6.10+/-3.98) was higher than in the low-grade gliomas (1.74+/-0.57) ( P<0.05). Echoplanar diffusion, perfusion MRI and multivoxel proton MRS can offer diagnostic information, not available with conventional MRI, in the assessment of glioma grade.     

Diverse patterns of acid-base abnormalities associated with a modified sigmoid neobladder

In this study, we analyzed the pattern of metabolic acidosis in patients following the construction of a sigmoid neobladder and then search for the risk factors which affecting this. In 23 men aged 43-73 years and nine women aged 49-74 years who underwent sigmoid neobladder surgery, we performed physical examinations and blood tests every 3 months for 13-75 months (38.7+/-16.6: mean+/-SD). We monitored acid-base balance, serum electrolytes, creatinine, lipid and liver function in patients for up to 6 years postoperatively. Creatinine clearance over 24 h was determined preoperatively. According to pH and base excess measured during follow-up, patients were classified into three groups (normal, 17 patients; temporary acidosis, eight patients; persistent acidosis, seven patients). Patients with temporary acidosis could compensate spontaneously by 1 year without being given sodium bicarbonate; those with persistent acidosis could not compensate spontaneously and five of them required medication with sodium bicarbonate after 1 year. Serum creatinine in patients with persistent acidosis was consistently higher during follow-up than in the other two groups. Preoperative creatinine clearances in the normal, temporary, and persistent groups were 94.25+/-27.47, 95.19+/-18.63, and 69.18+/-16.18 ml/min/1.73 m(2), respectively, being significantly lower in the persistent group ( P<0.05). In this group, patients with creatinine clearances less than 70 ml/min/1.73 m(2) could not compensate for metabolic acidosis. Normal and temporary groups showed different changes of serum chloride and bicarbonate during follow-up (respectively higher and lower) although the renal functions of the two groups were similar. Chloride and bicarbonate varied reciprocally with pH and base excess. Temporal hyperchloremic metabolic acidosis was observed until a year after surgery. In conclusion, temporary acidosis can be caused in some patients in spite of normal renal function, although it is difficult to predict it. In addition, careful follow-up is required, especially in patients with a creatinine clearance <70 ml/min/1.73 m(2) who can encounter persistent acidosis.     

Growth hormone releasing hormone test for infertile men with spermatogenetic maturation arrest

PURPOSE: Growth hormone has an important role in the function of the male reproductive system. We investigated infertile men with impaired growth hormone secretion. MATERIALS AND METHODS: Growth hormone status was studied in 8 fertile men and 9 infertile men with azoospermia due to spermatogenetic maturation arrest. Growth hormone releasing hormone, the specific stimulatory neurohormone, was used in the growth hormone stimulation test. A dose of 100 microg. of growth hormone releasing hormone was infused intravenously and serum growth hormone concentrations were measured at 0, 15, 30, 60, 90 and 120 minutes. Serum follicle-stimulating hormone, luteinizing hormone, prolactin, testosterone and estradiol were also measured before the test. RESULTS: Serum follicle-stimulating hormone concentrations were significantly increased in the azoospermic group and basal levels of growth hormone were similar to those in the control group. Serum growth hormone concentrations increased after injection of growth hormone releasing hormone and the levels of growth hormone peaked after 30 minutes in both groups. At time 30 minutes growth hormone levels had decreased significantly more in the azoospermic group than in the controls. Men with azoospermia due to spermatogenetic maturation arrest had a low response to the growth hormone releasing hormone test. CONCLUSIONS: Relative growth hormone insufficiency, which may be caused by reduced reactivity to growth hormone releasing hormone in pituitary growth hormone secretory cells, is strongly related to spermatogenic dysfunction.