Calcium movement of sarcoplasmic reticulum from hindlimb suspended muscle

The function of the sarcoplasmic reticulum (SR) was examined in the slow soleus and fast extensor digitorum longus (EDL) muscles of rats submitted to 14 days of weightlessness produced by hindlimb suspension (HS). Ca2+ uptake, Ca2+ release and passive Ca2+ leakage through the SR membrane were investigated using a method of caffeine-induced contracture on the single mechanically skinned fibers. In the SR of suspended soleus muscles, the rate of Ca2+ uptake was higher than in the control muscles. However, there was no difference between the suspended and control muscles in the rate of Ca2+ uptake of the SR in EDL after HS. In soleus muscles, Ca2+ movements of the SR from the suspended muscle acquired the properties that were similar to those of the control fast muscle. The study of Ca2+ leakage showed that the velocity and amount of passive Ca2+ leakage from SR in soleus and EDL were apparently increased after HS. The results suggested that the functional properties of the SR membrane in slow and fast muscles were changed after HS.

Transient suppression of pancreatic endocrine function in patients following brain death

To investigate pancreatic endocrine function in brain-dead patients, an intravenous glucose tolerance test (i.v. GTT) was performed in 8 brain-dead subjects maintained using the combined administration of vasopressin (ADH) and catecholamines during the first 3 days following the onset of brain death. Ten healthy adults served as control subjects. Although plasma glucose concentrations markedly increased and exceeded 300 mg/dl in most subjects just after the onset of brain death, they decreased to less than 200 mg/dl in most subjects after 24 h. The early insulin release also was significantly lower in brain dead subjects compared to controls (p < 0.01). The late insulin release was not decreased compared to controls but rather increased, which was accompanied by decreased glucose disappearance rate. The early insulin release recovered rapidly during the first 3 days following brain death without significant changes in the plasma hormone concentrations such as epinephrine, human growth hormone, thyroid-stimulating hormone, triiodothyronine, thyroxine, cortisol, and glucagon. The early insulin release and the plasma glucose concentration just before i.v. GTT was negatively correlated (R = -0.55, p < 0.05). We suggest awaiting recovery from hyperglycemia and early insulin release provides a reasonable approach to transplantation of the pancreas.

A novel function for nucleoside diphosphate kinase in Drosophila

Nucleoside diphosphate (NDP) kinase is an enzyme that transfers the gamma-phosphate of nucleoside triphosphates to nucleoside diphosphates. Besides this well-defined role, recent evidence suggests that NDP kinase may be implicated in a wide variety of essential cellular processes. In this paper, we showed that the NDP kinase of Drosophila exhibited protein kinase activity as well as autophosphorylation. Ovalbumin was phosphorylated with guanosine 5'-(3-O-thio)triphosphate (GTP gamma S) or ATP. Protein kinase activity was not detected in NDP kinase mutant, abnormal wing discs (awd). These results suggest that this activity could be one of the functions of NDP kinase essential for normal fly development, since awd gene is lethal.

The role of tumor necrosis factor and nitric oxide in the acute cardiovascular response to endotoxin

OBJECTIVE

This study was designed to examine the differential effects of tumor necrosis factor (TNF) and nitric oxide on the acute cardiovascular changes that occur in response to endotoxemia.

SUMMARY BACKGROUND DATA

Recent studies have suggested that some, if not all, of the cardiovascular effects of TNF are mediated through release of nitric oxide. However, the mechanisms through which TNF and nitric oxide induce hypotension and shock in vivo in response to systemic endotoxemia remain poorly characterized, despite current interest in the use of nitric oxide antagonists to ameliorate septic shock.

METHODS

A reproducible model of endotoxemia was established in adult Sprague-Dawley rats. The acute cardiovascular changes that occur after bolus infusion of endotoxin was then determined in rats treated with either TNF antibody, N-methyl arginine, or both.

RESULTS

Inhibition of either TNF or nitric oxide restores mean arterial blood pressure to normal after endotoxemia (p < 0.05). However, nitric oxide exerts its effects principally on the peripheral vasculature, whereas TNF appears to act on the myocardium. A combination of TNF antiserum pretreatment and N-methyl arginine administration is necessary to return mean arterial blood pressure to normal 60 minutes after endotoxin infusion.

CONCLUSION

Tumor necrosis factor and nitric oxide mediate the acute cardiovascular effects of endotoxemia through distinct mechanisms. Nitric oxide is released as a result of both TNF-dependent and TNF-independent mechanisms, whereas the cardiovascular effects of TNF are only partially mediated through nitric oxide.

Cross-sectional transmission electron microscopy of ZnO tetrapod-like particles

ZnO tetrapod-like particles having legs as long as several tens of micrometers have been observed by cross-sectional electron microscopy. The specimen is prepared by a new method where a photo-resist suspension of the particles fills up holes of an electron microscopy grid and is solidified for the subsequent ion-milling. Electron diffraction and high-resolution electron microscopy of a section of a ZnO tetrapod reveal the orientation relationship among its four legs, which enables us to discuss on the growth mechanism of these particles.

[Double cancers of renal cell carcinoma and testicular seminoma: a case report]

A case of metachronous presentation of renal cell carcinoma and testicular seminoma is reported. A 48-year-old man underwent left radical nephrectomy for a renal tumor on September 4, 1991. Pathological examination revealed clear cell carcinoma with no capsular penetration. There was no evidence of distant metastases. During postoperative follow-up, he noticed a painless left testicular induration in July, 1994. Serum human chorionic gonadotropin beta subunit as a tumor marker was elevated. Left radical orchiectomy was performed on October 17, 1994. Pathological examination revealed an anaplastic seminoma localized within the testis. Chest X-ray was normal and CT of the abdomen demonstrated no evidence of retroperitoneal lymphadenopathy. The patient was diagnosed as clinical stage I left testicular seminoma. He was free of disease 8 months postoperatively. Including our case, 15 cases of clinically detected double cancers of renal cell carcinoma and testicular germ cell tumor have been reported worldwide. This is the first case of a metachronous presentation of these two cancer types preceded by renal cell carcinoma.

Inhibition of neutrophil superoxide generation by hypericin, an antiretroviral agent

We previously reported that phorbol 12-myristate 13-acetate (PMA)-induced superoxide (O2.-) generation of neutrophils was inhibited by hypericin, a photosensitizing pigment found in St. Johnswort (herb Hypericin triquetrifolium Turra), via a mechanism involving protein kinase C (PKC). To obtain further insights into the mechanism of inhibition, the effects of hypericin on stimulation-dependent O2.- generation and related enzymes of neutrophils were investigated. Hypericin inhibited O2.- generation of neutrophils induced by PKC-dependent and -independent stimuli in a light- and concentration-dependent manner. Oxygen was required for the light-dependent inhibition by hypericin. NADPH oxidase activity in a cell-free system and TNF-alpha-induced tyrosyl phosphorylation of neutrophil proteins were also inhibited by hypericin in a concentration- and light-dependent manner. However, tyrosine kinase of p60src, an enzyme not bound to a membrane, was not inhibited either in the light or in the dark. Oxygen uptake of neutrophils by photosensitization with hypericin resulted in the formation of singlet oxygen (1O2), O2.-, and hydroxyl radical (.OH) and enhanced lipid peroxidation. The formation of 1O2 was inhibited by azide, a quencher of 1O2, but not by desferrioxamine (DSF), a ferric ion chelator. By contrast, both generation of .OH and lipid peroxidation were inhibited by DSF but not by azide. Furthermore, PMA-induced O2.- generation inhibited by hypericin partially recovered in the presence of azide but not DSF. These results suggested that the light-dependent inhibition of O2.- generation by hypericin might be due to inhibition of tyrosine kinase, PKC, and NADPH oxidase via an oxygen-dependent mechanism, possibly through both Type I and II photosensitization mechanisms.

Blood vessel invasion in metastatic nodes for development of liver metastases in colorectal cancer

BACKGROUND/AIMS

We assessed the importance of blood vessel invasion (BVI) by cancer in the metastatic lymph nodes for the development of liver metastases in colorectal cancer.

PATIENTS AND METHODS

The presence of BVI in the primary growth and in the lymph nodes was reviewed in 384 specimens.

RESULTS

In cases with and without BVI in the nodes, the incidence of liver metastases was 49% and 10%, respectively (p < 0.01). The highest incidence of liver metastases was observed in patients with BVI both in the primary tumor and in the metastatic nodes. The next to the highest incidence was observed when BVI was present not in the primary lesion but in the metastatic nodes. When considering the number of metastatic nodes, the incidence of liver metastases was high in cases with BVI in the nodes regardless of the number of metastatic nodes.

CONCLUSION

These data suggest that the BVI in the metastatic nodes is an important factor for the development of liver metastases.

Oxygen-dependent regulation of mitochondrial energy metabolism by nitric oxide

To elucidate the role of nitric oxide (NO) in the regulation of mitochondrial function, the effect of NO on energy transfer reactions was examined under different oxygen tensions. Mitochondrial respiration was remarkably inhibited by NO resulting in the inhibition of ATP synthesis in a concentration-dependent manner. In the presence of succinate, respiration, respiratory control by ADP, and ATP synthesis recovered completely at certain times after adding NO. The inhibitory action of NO continued significantly longer under physiologically low oxygen concentrations (such as the cytosolic level) than at high concentrations. In the presence of various substrates, such as pyruvate malate, succinate, and ascorbate tetramethyl paraphenylenediamine, NO also inhibited the uncoupled respiration in an oxygen- and concentration-dependent manner. The inhibition of respiration by NO was stoichiometrically suppressed by oxyhemoglobin. When added to a mitochondrial suspension, NO rapidly disappeared from the medium particularly at high oxygen tension. However, the rate of NO disappearance was significantly lower under low oxygen tension. Thus, under cytosolic oxygen concentration, NO might play an important role in the regulation of mitochondrial energy metabolism.

[Prognostic factors in uterine cervical and corpus cancer]

We have studied the prognostic factors for cancer of uterine cervix and corpus. Prognostic factors for cervical cancer include clinical stage, histological type, pelvic and paraaortic lymph node metastasis and CPL classification of carcinoma. Prognostic factors for cancer of uterine corpus are concerned with clinical stage, histological type and histological differentiation, muscle invasion, lymph node metastasis, perineal washing cytology and so forth. The clinical stage of course, reflects the prognosis. Although one of the important prognostic factors is lymph no metastasis, there may be recurrence in patients with a poor prognosis in cases in which lymph node metastasis has not been observed. In order to distinguish such cases and to improve their prognosis, it is important to provide treatment individually but combined chemotherapy or radiation therapy, for example, with efforts to detect various prognostic factors.

Pharmacologic treatment of intimal hyperplasia after metallic stent placement in the peripheral arteries. An experimental study

RATIONALE AND OBJECTIVES

To evaluate the efficacy of oral administration of cilostazol, an antithrombotic agent, for the prevention of thrombotic occlusion and intimal hyperplasia after stenting.

METHODS

Single-bodied Z-stents were placed in the iliac arteries of 23 dogs. Before stenting, an embolizing coil was introduced into the right femoral artery to reduce blood flow in the right iliac artery. Eleven dogs were given cilostazol orally, and the other 12 were unmedicated as a control group. The dogs were killed at 4, 13, and 24 weeks.

RESULTS

Intraluminal narrowing due to thrombus was observed in 25% of dogs in the control group but in none of the dogs in the cilostazol group. The thickness of the neointima was significantly thinner in the cilostazol group than in the control group at 24 weeks on the noncoiled side (P < 0.05), and at 4 and 24 weeks on the coiled side (P < 0.01).

CONCLUSIONS

These results suggest that oral administration of cilostazol is an effective method of preventing thrombotic occlusion and intimal hyperplasia after stenting.

Effect of the antiretroviral agent hypericin on rat liver mitochondria

The photosensitizing effect of hypericin (HY), an antiretroviral agent, on the functions of isolated rat liver mitochondria has been investigated. The respiratory control ratio (RCR), ADP/O and membrane potential of mitochondria were decreased by HY in a light-dependent manner. Uncoupled respiration of mitochondria in the presence of succinate was also inhibited by HY in a light-dependent manner. The ID50 of hypericin for these inhibitions was approximately 0.5 microM. These inhibitory effects of HY were not observed when photosensitization was conducted under anaerobic conditions and were not affected by desferrioxamine (DSF) or superoxide dismutase (SOD). Upon photosensitization of HY, mitochondria consumed oxygen in the absence of respiratory substrate with concomitant formation of thiobarbituric acid reactive substance (TBARS). The amount of oxygen consumed was 100-times greater than that of TBARS formed. The oxygen uptake was partially inhibited by NaN3, and formation of TBARS was inhibited by DSF. Upon photosensitization of HY in the presence of mitochondrial membranes, the electron spin resonance (ESR) signal of 2,2-dimethyl-5-hydroxy-1-pyrrolidinyloxyl (DMPO/.OH) was increased by a mechanism which was suppressed by DSF. An ESR signal for singlet oxygen bound to 2,5-dimethylfuran, 2,2,6,6-tetramethyl-4-piperidone (TEMP) was also detected under light in the presence of mitochondria. This signal of the TEMP-N-oxyl radical (TEMPO) was decreased by azide, which physically quenches singlet oxygen, but was increased by DSF. These results indicate that HY might inhibit mitochondrial functions by a type II photodynamic mechanism but that lipid peroxidation of biological membranes through an active oxygen-mediated photodynamic mechanism is not involved.

Compartmental organization of layer IVA in human primary visual cortex

Immunostaining for three neuronal proteins, nonphosphorylated neurofilament protein (with antibody SMI-32), calbindin, and parvalbumin, was used to examine the organization of layer IV in human primary visual cortex (area 17 or V1) specifically to determine whether, similar to the case in macaque V1, layer IVA is present and is divided into neurochemically distinct compartments. All three proteins are expressed by neurons that are unevenly distributed in layer IV of human V1; immunostaining for each protein includes a thin band corresponding to layer IVA of classic cytoarchitectonic studies. In this band, nonphosphorylated neurofilament protein immunoreactivity is present in relatively broad clusters of pyramidal cell somata and dendrites that appear as upwardly protruding parts of intense immunostaining in layer IVB, whereas immunoreactivity for calbindin and parvalbumin exists in somata of nonpyramidal neurons and in thin, dense clusters of punctate profiles. In tangential sections through layer IVA, the three proteins are seen in distinct compartments. Calbindin- and parvalbumin-immunostained neurons make up a thinly walled honeycomb or lattice, whereas neurons immunostained for nonphosphorylated neurofilament protein occupy the central lacunae. Direct comparison shows that neurons immunostained for calbindin occupy regions in layer IVA complementary to those immunostained for nonphosphorylated neurofilament protein. These data demonstrate a basic similarity in the organization of layer IV in macaques and humans. Layer IVA specifically is organized into complementary and neurochemically distinct compartments, including what appears to be a geniculocortically innervated and parvicellular-driven lattice and the interstitial lacunae formed by the periodic, upward protrusion of magnocellular-dominated layer IVB neurons.

Acute renal failure associated with Candida albicans infection

A 16-year-old male with a long history of steroid-responsive nephrotic syndrome developed fever, abdominal pain, thrombocytopenia and acute renal failure. The clinical course and renal histology were similar to, but not typical of, haemolytic uremic syndrome. Positive cultures (throat, oesophagus, stool), an elevation in serum levels of specific antibody and fungal polysaccharide (1,3) beta-D-glucan and response to the antifungal therapy indicated an association between this syndrome and infection with Candida albicans.

A-band movement and junctional gap dissociation during caffeine-induced contracture of skeletal muscle fibers

The action of caffeine on the myofibril profile of the sarcomere and the junctional gap of the intracellular membrane was studied ultrastructurally. When a high concentration of caffeine (5 mM) was applied, the movement of the A-band in sarcomeres dissected from the central portion of single muscle fibers was greater than that in sarcomeres dissected from the proximal and distal portions of the fiber. The amount of calcium released from the sarcoplasmic reticulum of the caffeine-treated muscle was greater in the terminal cisternae located on the narrow I band than in the wide I band, as determined by electron-probe analysis of ultrathin cryosections. The junctional gap was clearly expanded after caffeine treatment, resulting in an irreversible change in muscle contractility. These structural alterations may lead to the distinctive development of tension induced by caffeine. The expansion of the gap may also cause excitation-contraction uncoupling.

The Brn-3 family of POU-domain factors: primary structure, binding specificity, and expression in subsets of retinal ganglion cells and somatosensory neurons

A search for POU domain sequences expressed in the human retina has led to the identification of three closely related genes: Brn-3a, Brn-3b, and Brn-3c. The structure and expression pattern of Brn-3b was reported earlier (Xiang et al., 1993); we report here the structures and expression patterns of Brn-3a and Brn-3c. Antibodies specific for each Brn-3 protein were generated and shown to label only ganglion cells in a variety of vertebrate retinas. A complex pattern of strongly and weakly immunolabeled ganglion cells was observed in mouse, cat, and monkey retinae. In mouse and cat retinae, Brn-3a and Brn-3b proteins are found in a large fraction of ganglion cells, whereas Brn-3c is present in fewer ganglion cells. In the cat retina, anti-Brn-3a immunoreactivity was strong in the small ganglion cells (gamma cells) and weak in the remaining ganglion cells (alpha and beta cells); anti-Brn-3b immunoreactivity was present in all ganglion cells; and anti-Brn3c immunoreactivity was confined to the small ganglion cells. Immunolabeling of macaque retinae following retrograde labeling from the lateral geniculate nucleus revealed strong anti-Brn-3a immunoreactivity in a minority of retrogradely labeled P-type ganglion cells, and weak Brn-3a immunoreactivity in all of the remaining P- and M-type ganglion cells. In the same retinae, strong anti-Brn-3b immunoreactivity was seen in nearly all P-type ganglion cells and weak immunoreactivity in nearly all M-type ganglion cells. Each of the Brn-3-specific antibodies also labeled subsets of neurons in the dorsal root and trigeminal ganglia, suggesting that primary somatosensory neurons and retinal ganglion cells share genetic regulatory hierarchies. In vitro selection of an optimal DNA binding site using the Brn-3b POU domain has revealed a consensus [(A/G)CTCATTAA(T/C)] that is recognized by each of the Brn-3 POU domains and is distinct from binding sites previously described for other POU domain proteins.

Low oxygen extraction despite high oxygen delivery causes low oxygen consumption in patients with burns recovering slowly from operative hypothermia

BACKGROUND

Patients with burns who eventually succumbed to their injuries tended to recover more slowly from operative hypothermia than those who survived. Slower recovery was associated with a lower postoperative oxygen consumption (VO2). We have now investigated whether this was due to impairment of oxygen delivery or extraction.

METHODS

This study was performed in 13 adult patients with severely burns. One hundred four measurements of VO2 by indirect calorimetry were made during recovery from 23 episodes of operative hypothermia in 11 patients. Sixty-six measurements of oxygen transport variables by balloon-tipped pulmonary artery catheter were made after 17 episodes of operative hypothermia in six patients. Body temperature was monitored in the urinary bladder.

RESULTS

The rate of temperature rise (T) showed a strong positive correlation with VO2 measured both by indirect calorimetry (r = 0.91, p < 0.001) and by balloon-tipped pulmonary artery catheter (r = 0.83, p < 0.001). Oxygen delivery (DO2) was above normal in nearly all patients. Oxygen extraction was low in patients recovering slowly (T < 1.0 degree C/hr) and high in those recovering quickly (T > or = 1.0 degree C/hr). During fast recovery VO2 (373 +/- 77 ml.min-1.m-2; mean +/- SD) was approximately three times normal and was independent of DO2. In contrast, a strong linear relationship existed between VO2 and DO2 during slow recovery (r = 0.76, p < 0.001).

CONCLUSIONS

Patients with burns with slow recovery from operative hypothermia exhibited impaired oxygen extraction and dependence of VO2 on DO2 over a wide range. This picture resembles that in patients with critical illness.

Differences in body temperature changes during dressing change in surviving and non-surviving burned patients

Change in body temperature (delta BT) while dressings were being changed was measured in 52 extensively burned adults. The patients were divided into four groups based on outcome and the prognostic burn index (PBI; age + burn index): group I (15 survivors, PBI less than or equal to 80), group II (15 survivors, PBI between 80 and 120), group III (14 non-survivors, PBI between 80 and 120), and group IV (eight non-survivors, PBI greater than 120). The body temperature before the change of dressings was the same in the four groups. The mean(s.d.) delta BT in all patients was -0.5(0.8) degrees C. The magnitude of delta BT was not related to the time required for changing dressings (r = 0.04) or to the non-epithelialized area present at each change of dressings (r = -0.05). All groups showed a similar increase in delta BT during the early period after the burn, but in group I it began to decrease progressively after the 16th day after the burn (P < 0.05). A reduction in delta BT was noted in group II from day 25, whereas it was unchanged in groups III and IV (P < 0.05). It also significantly increased 2 days before the diagnosis of sepsis (P < 0.05). These results emphasize that delta BT may provide useful information about prognosis and the development of sepsis.

[The effect of takusha and kagosou on calcium oxalate renal stones in rats]

We examined the inhibitory effect of the two Kampo medicines, takusha and kagosou on the formation of calcium oxalate renal stones induced by ethylene glycol (EG) and 1 alpha(OH)D3 (1 alpha-D3) in rats. Wistar strain rats were divided into 4 groups (A: normal control, B: stone, C: kagosou, D: takusya). There was no significant difference in urinary calcium excretion or oxalate excretion between the stone group and kampo medicine groups. The calcium content of the kidneys was significantly lower in the takusha group than in the other two groups (Stone group and kagosou group). Takusha was effective in preventing oxalate stone formation in rats. Kagosou, which had strong inhibitory effect on calcium oxalate crystal growth and aggregation in vitro as well as takusha, was not effective against in vivo calcium oxalate stone formation in rats. These findings suggest that takusha prevents the formation of calcium oxalate stone by inhibiting calcium oxalate crystal growth and aggregation.

Connections between the pulvinar complex and cytochrome oxidase-defined compartments in visual area V2 of macaque monkey

We examined the distribution of pulvinar afferents to visual area V2 of macaque monkey cerebral cortex in relation to the distribution of the metabolic enzyme cytochrome oxidase (CO). V2 contains three sets of stripelike subregions that are marked by differential staining for CO, and which have different corticocortical connections. The pulvinar provides the major subcortical input to V2, and this input is known to be patchy. We were interested to determine how the pattern of pulvinar afferents relates to the layout of the three stripelike compartments that characterize V2. We made large injections of WGA-HRP into the pulvinar (labelling both the inferior and lateral divisions) and mapped the resulting orthograde terminal and retrograde cell label within V2. We observed pulvinar terminal label mainly in lower layer 3 (at the layer 4 border), with light label in layer 1 as well; terminal label in layers 3-4 was distributed in discrete patches with faint bridges of light label between. Comparison with adjacent sections stained for CO or Cat-301 showed that pulvinar terminal zones aligned precisely with regions of increased CO staining, and targeted both "thick" (Cat-301+) and "thin" CO-rich stripes, avoiding the pale stripes (which aligned with the faint bridges of terminal label). Retrogradely labelled cells were found in layers 5A and 6, but the bulk of the feedback to pulvinar arose from layer 6 rather than layer 5 (unlike V1, where feedback to pulvinar arises primarily from layer 5B). These results show that the increased CO staining in certain subregions of V2 is closely correlated with the presence of thalamic terminals from the pulvinar. Although we cannot rule out the possibility that different sets of pulvinar neurons project to different CO compartments in V2, the presence of a prominent thalamic input shared by the "thick" and "thin" CO stripes (which receive different V1 afferents and make different feedforward projections to other visual cortical areas) could underlie the preferential intrinsic interconnections shown to exist between these V2 subregions and suggests another potential source of integration between the two cortical visual streams.

The inhibitory effect of kampou extracts on in vitro calcium oxalate crystallization and in vivo stone formation in an animal model

Kampou medicine is a traditional Japanese therapeutic system which originated in China and was used to treat various diseases for hundreds of years until it was superseded by Western medicine. In recent years, there has been a resurgence of interest in Kampou medicine among many physicians. Unfortunately, however, little evaluation has been performed using objective scientific methods until now, and the pharmacodynamics of Kampou medicine are still unclear. Generally speaking, Kampou medicine has been shown to have fewer side-effects than Western medicine based on the experience gained from its long usage. We first selected 16 Kampou extracts for screening as possible calcium oxalate stone prophylactic agents in vitro. This resulted in the selection of two kinds of Kampou extracts, Takusya and Kagosou, as potential Kampou extracts for stone prophylaxis. Next, these two Kampou extracts were tested in vivo for their effects on stone formation in an animal model. Takusya showed significant stone prophylaxis, while Kagosou did not. Lastly, Chorei-to, which contains Takusya and has been approved for prescription as a Kampou medicine for urolithiasis patients in Japan, was examined in vivo at two different concentrations. As a result, a low dose of Chorei-to which corresponded to the human daily dose per unit of body weight exhibited apparent stone prophylaxis, despite the disadvantage of decreasing citrate excretion. In contrast, high doses of Chorei-to did not exhibit stone prophylaxis in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed improvement in exercise capacity with restoration of sinoatrial node response in patients after combined treatment with surgical repair for organic heart disease and the Maze procedure for atrial fibrillation

BACKGROUND

Although the Maze procedure successfully restores sinus rhythm in patients with heart disease and atrial fibrillation, it is still uncertain whether an addition of the Maze procedure in cardiac surgery is beneficial for exercise performance of the patients after surgery.

METHODS AND RESULTS

The Maze procedure was performed in 25 patients (age, 37 to 70 years) during valve surgery (18 patients) or closure of atrial septal defect (7 patients). A cardiopulmonary exercise test using ramp incremental protocol (15 W/min) was performed before and 1 month, 6 months, and 1 year after surgery. Sinus conversion was obtained in 23 of 25 patients 1 month after surgery. However, sinoatrial (SA) node response to exercise was attenuated by surgery: Mean heart rate (HR) was 83 +/- 13/min at rest, 94 +/- 13/min at 60 W, and 107 +/- 17/min at peak exercise. Peak oxygen uptake (PVO2) was unchanged at this period (before, 17.6 +/- 4.5 mL.min-1.kg-1; 1 month after, 17.5 +/- 4.2 mL.min-1.kg-1). Thereafter, SA node response was restored 6 months after surgery: Mean HR was 84 +/- 13/min at rest, 104 +/- 16/min at 60 W, and 130 +/- 20/min at peak exercise (P < .01 versus 1 month). PVO2 was also improved at this period (20.7 +/- 4.0 mL.min-1.kg-1, P < .01). The increase in PVO2 from 1 month to 6 months after surgery was correlated with the increase in peak HR (y = 0.73x +/- 3.6, r = .79). There were no further changes in heart rate response or PVO2 from 6 months to 1 year after surgery.

CONCLUSIONS

Atrial fibrillation was successfully treated by combined treatment with surgical repair for organic heart disease and the Maze procedure. However, SA node response to exercise was attenuated early after surgery. Thus, exercise capacity was improved at the late phase after surgery, which was related to the extent of restoration in SA node response.

Inhibition of stimulus-specific neutrophil superoxide generation by alpha-tocopherol

Alpha-tocopherol but not 2-carboxy-2,5,7,8-tetramethyl-6-chromanol (trolox or CTMC) and 2,2,5,7,8 pentamethyl-6-hydroxy chromane (PMC), derivatives of alpha-tocopherol, inhibited the superoxide (O2-.) generation of rat peritoneal neutrophils (RPMN) induced by phorbol 12-myrisate 13-acetate (PMA). ID50 for neutrophils obtained from the peritoneal cavity of rat and guinea pig was about 1microM. This concentration, however, was much lower than that for the inhibition of PMA-activated phospholipid-dependent protein kinase (PKC) (ID50 = 30 microM). The alpha-tocopherol sensitive O2-. generation was also observed in neutrophils induced by dioctanoylglycerol (diC8) and calcium ionophore A23187 but not by formylmethionyl-leucyl-phenylalanine (FMLP), opsonized zymosan (OZ) and sodium dodecyl sulfate (SDS). The pattern of inhibition by alpha-tocopherol was quite similar to that of staurosporine, a specific inhibitor of PKC. The alpha-tocopherol content of RPMN was 12 ng/10(6) cells and a linear increase to 200 ng/10(6) cells by addition of alpha-tocopherol to the cell suspension corresponded with an increased inhibition of O2-. generation. These results indicate that both the chemical structure and the content of alpha-tocopherol might be important factors in O2-. generation by neutrophils.

Alzheimer and beta-amyloid-treated fibroblasts demonstrate a decrease in a memory-associated GTP-binding protein, Cp20

The two proteins most consistently identified in the brains of patients with Alzheimer disease (AD) have been beta-amyloid and tau, whose roles in the physiology or pathophysiology of brain cells are not fully understood. To identify other protein(s) involved in AD that have been implicated in physiological contexts, we undertook to analyze a specific memory-associated protein, Cp20, in fibroblasts from AD and control donors. Cp20, a GTP-binding protein that is a member of the ADP-ribosylation factor family, was significantly decreased in fibroblasts from AD patients. Normal control fibroblasts exposed to 10 nM beta-amyloid, the same concentration that induced AD-like K+ changes in control fibroblasts, showed a similar decrease in Cp20. Since it has been previously demonstrated that Cp20 is a potent regulator of K+ channels, these findings suggest that changes in this memory-associated protein may explain previously observed differences in AD K+ channels and suggest a pathophysiologic involvement linked to soluble beta-amyloid metabolism that could contribute to the characteristic memory loss of AD.