Medullary nephrocalcinois and primary hyperaldosteronism - A rare and under recognised association.

ABSTRACT: Medullary nephrocalcinosis is an uncommon manifestation of primary hyperaldosteronism (PHA) and the exact etiology of this association is still debated. Here we report three cases of PHA with medullary nephrocalcinosis and how medullary nephrocalcinosis in one patient led to misdiagnosis as renal tubular acidosis (RTA). Although PHA and RTA can share overlapping symptoms, careful evaluation of clinical presentation, biochemical tests, and imaging studies are essential to differentiate between the two conditions and ensure appropriate management. Also, awareness of this uncommon manifestation of PHA is essential to avoid misdiagnosis as tubulopathy, as this may delay the treatment.

Using a colonoscopy snare to safely remove large papillary bladder tumors.

A standard 22F rigid cystoscope with a 6.9F Bard colonoscopy snare connected to an Erbe power source at 25 W was utilized to remove bladder tumors. A loop was used to resect the base of the lesion and underlying muscle. Snare resection of papillary vesical tumors is a safe, easy method that can complement standard loop resection and be a valuable asset to urologists. No interference with histopathologic examination was encountered with this technique.

Vasovenous fistula after vasectomy.

PIP: Reported is the first known case in which vasovenous fistula occurred as a complication of vasectomy. A 44-year-old US man, who had undergone a routine vasectomy 3 months earlier, presented with hematospermia and gross hematuria. Cytoscopy revealed blood emanating from the left ejaculatory duct. Left scrotal exploration demonstrated a vein transversing into the area of the vas deferens where previously placed clips were present. Histopathological examination revealed multiple vascular structures, abnormal in number and caliber, which were adherent to the vas deferens. It is postulated that, in this case, the hematoma occurred as a result of bleeding from a vein adjacent to the surgical clip. The inflammatory response to the clip may then have involved the neighboring injured vein, resulting in fistula formation. This rare complication can be averted through efforts not to injure vascular structures during vasectomy.^ieng

Effect of long-term in vivo treatment with imipramine on the oxidative energy metabolism in rat brain mitochondria.

The effects of long-term administration of the tricyclic antidepressant imipramine on energy metabolism of rat brain mitochondria were examined. Intraperitoneal administration of the drug resulted in significant stimulation of the state 3 respiration rates with glutamate, pyruvate+malate, beta-hydroxybutyrate and succinate as the substrates. The effect was evident within a week of imipramine administration and was sustained through the second week of the drug treatment. State 4 respiration rates were also found to be increased in general. However, the respiration with ascorbate+TMPD as the electron donor system decreased. The intramitochondrial content of cytochrome b and c+c1 increased in the first week of the drug treatment; that of aa3 cytochrome increased only in the second week.

Oxidative stress in radiation-induced interstitial pneumonitis in the rat.

The involvement of free radical metabolism in the pathogenesis of interstitial pneumonitis was investigated in an animal model. Male Wistar rats were irradiated at the thoracic region by gamma-rays from a 60Co source. Histopathological examination confirmed that 50% of the rats developed pneumonitis between 2 and 8 weeks following a single dose of 14 Gy. Parallel biochemical studies in the lung of these rats showed that mitochondria and microsomes had higher levels of lipid peroxidation. In the cytoplasmic fraction of the lung the activities of superoxide dismutase and catalase were markedly reduced in the pneumonitic rat. In lung mitochondria, however, the levels of these two enzymes were not significantly altered. On the contrary, lipid peroxidation and superoxide dismutase, as well as catalase activities in lung tissue in the non-pneumonitic group of the irradiated rat were comparable with that of control animals. The results indicate that free radical-induced oxidative stress following thoracic irradiation may be one of the causative factors in the development of interstitial pneumonitis.

Pheochromocytoma of urinary bladder: contemporary methods of diagnosis and treatment options.

Two patients with vesical pheochromocytoma are presented with a review of the literature. Imaging modalities for localizing extra-adrenal pheochromocytomas are reviewed with an overview of the commonly accepted treatment options. Successful treatment of this lesion requires a high index of suspicion based upon the patient's symptom complex, allowing preoperative preparation prior to surgical manipulation.

Is the first site of phosphorylation operative in rat brain mitochondria in early neonatal life? A critical re-evaluation.

The age-dependent changes in oxidative phosphorylation in rat brain mitochondria were studied in order to ascertain if the efficiency of phosphorylation with NAD(+)-linked substrates increases during the first month after birth. The state 3 respiration rates with all substrates tested increased with age but with distinctive developmental profiles for each substrate; the extent of increase was also substrate-specific. The ADP/O ratios obtained with all substrates, including NAD(+)-linked ones were comparable with the value for adult mitochondria right from the first postnatal week. The intramitochondrial cytochrome contents also increased with age; the different classes of cytochromes exhibiting different developmental patterns. Simultaneously there was an elevation in the serum concentrations of thyroid hormones up to the third postnatal week following which they declined. The increase in respiration rates was paralleled by decrease in the ratio of T4/T3 in the serum, thus suggesting that this ratio is a sensitive index for developmental profiles of substrate oxidation.

Protein kinase C substrate and inhibitor characteristics of peptides derived from the myristoylated alanine-rich C kinase substrate (MARCKS) protein phosphorylation site domain.

The phosphorylation sites in the myristoylated alanine-rich C kinase substrate or MARCKS protein consist of four serines contained within a conserved, basic region of 25 amino acids, termed the phosphorylation site domain. A synthetic peptide comprising this domain was phosphorylated by both protein kinase C and its catalytic fragment with high affinity and apparent positive cooperativity. Tryptic phosphopeptides derived from the peptide appeared similar to phosphopeptides derived from the phosphorylated intact protein. The peptide was phosphorylated by cAMP- and cGMP-dependent protein kinases with markedly lower affinities. In peptides containing only one of the four serines, with the other three serines replaced by alanine, the affinities for protein kinase C ranged from 25 to 60 nM with Hill constants between 1.8 and 3.0. The potential pseudosubstrate peptide, in which all four serines were replaced by alanines, inhibited protein kinase C phosphorylation of histone or a peptide substrate with an IC50 of 100-200 nM with apparently non-competitive kinetics; it also inhibited the catalytic fragment of protein kinase C with a Ki of 20 nM, with kinetics of the mixed type. The peptide did not significantly inhibit the cAMP- and cGMP-dependent protein kinases. It inhibited Ca2+/calmodulin-dependent protein kinases I, II, and III by competing with the kinases for calmodulin. In addition, the peptide inhibited the Ca2+/calmodulin-independent activity of a proteolytic fragment of Ca2+/calmodulin protein kinase II, with an IC50 approximately 5 microM. Thus, the phosphorylation site domain peptide of the MARCKS protein is a high affinity substrate for protein kinase C in vitro; the cognate peptide containing no serines is a potent but not completely specific inhibitor of both protein kinase C and its catalytic fragment.

Altered energy coupling in rat heart mitochondria following in vivo treatment with propranolol.

Effects of acute and chronic treatment with propranolol on oxidative phosphorylation in rat heart mitochondria were examined. Acute propranolol treatment resulted in inhibition of coupled respiration with pyruvate + malate and succinate as substrates. Chronic treatment resulted in decreased state 3 respiration rates with all the substrates employed. The net effect of propranolol treatment was decreased ATP-phosphorylation rates suggesting that this was possibly one of the modes of its cardiodepressant activity. Additionally, chronic propranolol treatment brought about a decrease in the content of cytochrome c + c1 in heart mitochondria. Estimation of propranolol concentrations in serum, whole tissue homogenate and heart mitochondria indicated that although the mitochondria accumulated the highest amount of the drug, the intramitochondrial concentration of the drug was one or two orders of magnitude lower than that which is required to bring about inhibition of respiration under in vitro conditions. Besides, the concentrations reached under acute and chronic treatment conditions were almost comparable. The results, therefore, suggest that the action of the drug in vivo may involve more intricate mechanisms than those observed under in vitro conditions.

Residual ethylene oxide determination in polymethyl methacrylate disks and intraocular lenses by headspace gas analysis and N,N-dimethylformamide extraction.

The residue in an ethylene oxide (EO)-exposed polymethyl methacrylate (PMMA) material [flat disk and intraocular lens (IOL)] was determined using three methods: semiautomatic and manual headspace methods and N,N-dimethylformamide (DMF) solvent extraction. Results from the analysis of three different sample configurations at three different EO concentrations are compared. Results from the DMF extraction of PMMA indicate that the headspace methods at 100 degrees C are not exhaustive with respect to recovery of total residual ethylene oxide. Furthermore, the manual headspace method appears to be slightly more effective than the semiautomatic injection headspace method. Sorption of EO and subsequent extraction is related to the surface area-to-volume ratio of the sample, with higher concentrations observed in samples with the high ratio.

Enhanced oxidative phosphorylation in rat liver mitochondria following prolonged in vivo treatment with imipramine.

1. Effects of prolonged in vivo administration of the tricyclic antidepressant drug imipramine on oxidative energy metabolism in rat liver mitochondria were examined. 2. Imipramine treatment resulted in an increase in state 3 respiration rates with all the substrates tested as early as one week after treatment; this was sustained through the second week of treatment. 3. The changes in respiration rates were accompanied by a selective increase in the intramitochondrial cytochrome aa3 and c + c1 contents after both one and two weeks of treatment. 4. Administration of imipramine did not alter the total liver protein content per g tissue, the mitochondrial protein content per g tissue or the mitochondrial yield. 5. Kinetic analyses of succinoxidase activity in terms of Arrhenius plots indicated possible alterations in mitochondrial membrane lipid milieu and membrane fluidity after the drug treatment, especially in the second week.