Escherichia coli ATP synthase (F-ATPase): catalytic site and regulation of H+ translocation

We discuss our recent results on the Escherichia coli F-ATPase, in particular its catalytic site in the beta subunit and regulation of H+ transport by the gamma subunit. Affinity labelling experiments suggest that beta Lys-155 in the glycine-rich sequence is near the gamma-phosphate moiety of ATP bound at the catalytic site. The enzyme loses activity upon introduction of missense mutations in beta Lys-155 or beta Thr-156 and changes catalytic properties upon introduction of other mutations. By analysis of mutations and their pseudo revertants, residues beta Ser-174, beta Glu-192 and beta Val-198 were found to be located near the glycine-rich sequence. The combined approaches of chemical labelling and genetics have been fruitful in visualizing the structure of the catalytic site. Analysis of mutations in the gamma subunit suggests that this subunit has an essential role in coupling catalysis with proton translocation.

F0F1-ATPase gamma subunit mutations perturb the coupling between catalysis and transport

We introduced mutations to test the function of the conserved amino-terminal region of the gamma subunit from the Escherichia coli ATP synthase (F0F1-ATPase). Plasmid-borne mutant genes were expressed in an uncG strain which is deficient for the gamma subunit (gamma Gln-14-->end). Most of the changes, which were between gamma Ile-19 and gamma Lys-33, gamma Asp-83 and gamma Cys-87, or at gamma Asp-165, had little effect on growth by oxidative phosphorylation, membrane ATPase activity, or H+ pumping. Notable exceptions were gamma Met-23-->Arg or Lys mutations. Strains carrying these mutations grew only very slowly by oxidative phosphorylation. Membranes prepared from the strains had substantial levels of ATPase activity, 100% compared with wild type for gamma Arg-23 and 65% for gamma Lys-23, but formed only 32 and 17%, respectively, of the electrochemical gradient of protons. In contrast, other mutant enzymes with similar ATPase activities (including gamma Met-23-->Asp or Glu) formed H+ gradients like the wild type. Membranes from the gamma Arg-23 and gamma Lys-23 mutants were not passively leaky to protons and had functional F0 sectors. These results suggested that substitution by positively charged side chains at position 23 perturbed the energy coupling. The catalytic sites of the mutant enzymes were still regulated by the electrochemical H+ gradient but were inefficiently coupled to H+ translocation in both ATP-dependent H+ pumping and delta mu H+ driven ATP synthesis.

Acromelic acid, a novel kainate analogue, induces long-lasting paraparesis with selective degeneration of interneurons in the rat spinal cord

A single systemic administration of acromelic acid, a novel kainate analogue (kainoid), induces a series of characteristic behavioral changes in association with selective damage of interneurons in the caudal spinal cord in adult rats. When an effective dose of acromelic acid (5 mg/kg) was systemically administered, forced extension of hindlimbs with or without cramps appeared in all rats. In the course of the intensified hindlimb extension, 10 of 16 rats suffered from generalized convulsive seizures during which 6 rats died without apparent neuropathological change. Of 4 surviving rats that experienced seizures, two developed long-lasting spastic paraparesis which remained unchanged for at least 3 months, whereas the other two were normal in behavior on the days following the administration. In lower doses (less than 4 mg/kg), the rats transiently displayed forced extension of hindlimbs, and in a higher dose (5.5 mg/kg), all rats died during an attack of severe generalized convulsion. Neuropathological changes were observed only in the rats with persistent paraparesis, in which neuron damage was identified selectively in small interneurons in the lumbosacral cord. The morphological change of the degenerated spinal interneurons resembles that of degenerated hippocampal CA1 pyramidal cells seen after systemic administration of kainate. Large motoneurons, spinal roots, and white matter of the spinal cord were well preserved. Unlike the case of systemic administration of kainate, other structures in the central and peripheral nervous system and muscles were morphologically intact except the hippocampal CA4 and the stratum moleculare-lacnosum in which there were reactive astrocytes. The regional difference between kainate-induced and acromelate-induced neuron damage suggests that systemically administered acromelic acid, a kainoid, induces selective neuron damage through activating a particular kainate receptor subtype. The clinicopathological feature of the paraparetic rats resembles closely that of stiffman syndrome, a progressive human neurological disorder with selective loss of interneurons in the spinal cord.

[Neuron damage in the rat spinal cord induced by acromelic acid]

A single systemic injection of acromelic acid, a novel kainate analogue, caused long-lasting spastic paraparesis in the rat. Two rats that developed paraparesis were neuropathologically examined one week and three months after the injection, respectively. Numerous degenerated neurons with marked reactive gliosis were scattered in the gray matter of the spinal cord of the rat with paraparesis for one week. Degenerated neurons were most abundant in the core part of lumbar and sacral segments. The cytometry on the 1st sacral segment disclosed that the number of small neurons was significantly decreased. No morphological sign of neuron damage was demonstrated in the rest of the central nervous system. These pathological changes were responsible for the development of characteristic behavioral changes which were quite different from those induced by kainic acid. The regional difference between the neuron damage induced by acromelic acid and that induced by kainic acid suggests the presence of plural kinds of kainate receptor subtypes in the rat central nervous system. This assumption is supported by receptor binding studies on glutamate receptor subtypes, indicating the low affinity of acromelic acid for both kainate and AMPA binding sites. Acromelic acid may exert its potent depolarizing and neurotoxic effects through activating a new class of kainate receptor subtypes.

[Clinical analysis of myasthenia gravis accompanied by invasive thymoma]

Over the last 20 years, 6 patients with myasthenia gravis and invasive thymoma have been seen in our Department. These patients underwent non-total excision cases. This represents 2.5 percent of 242 myasthenia gravis patients in our series. We can see 17 such patients in the literature in Japan including our cases. The age ranged 20 to 77 years and the ratio of male to female was 10:7. Post-operative therapeutic methods for invasive thymoma included irradiation, steroid therapy and combination chemotherapy. Every method showed good therapeutic results, but steroid therapy and chemotherapy showed especially good therapeutic effects in the early stage of the disease. Though these therapeutic effects were better than those obtained in other malignant tumors, thymomas tended to reappear within several years, when tumors showed no response to any therapeutic method. It is well known that steroid therapy reduces the level of antiacetylcholine receptor antibody, whereas chemotherapy also reduces antiacetylcholine receptor antibody. Over all 5-year survival rate was 53%, and the 10-year survival rate was 29%. Three out of 6 cases of death were due to myasthenic crisis (50%) and 2 out of 6 cases were due to invasive tumor itself (38%). These results suggested that total excision of the thymoma, if possible, and for the remaining tumor, high doses of adrenocorticosteroids and combination chemotherapy seem to be treatments of choice.

Effect of bovine herpesvirus-1 or parainfluenza-3 virus on immune receptor-mediated functions of bovine alveolar macrophages in the presence or absence of virus-specific serum or pulmonary lavage fluids collected after virus infection

The immune receptor-mediated functions of bovine alveolar macrophages (AM) inoculated in vitro with bovine herpesvirus-1 (BHV-1) or parainfluenza-3 (PI-3) virus were tested in the presence or absence of virus-specific antiserum or pulmonary lavage fluids collected from calves 6 days after inoculation with BHV-1 or PI-3 virus. The Fc and C3b phagocytic indices of noninoculated AM, collected from 6- to 16-week-old calves, ranged from 75 to 87 and 59 to 64, respectively, and the binding indices ranged from 5 to 8 and 22 to 28, respectively. Infection of AM with either BHV-1 or PI-3 virus had no significant effect on receptor-mediated phagocytosis or binding, with the exception of a significant (P less than 0.05) decrease, from 64 to 46, of the C3b phagocytic index of PI-3 virus-infected AM. The addition of lavage fluids, collected after BHV-1 or PI-3 virus infection, to AM infected with the respective virus caused a significant (P less than 0.05) decrease in phagocytic indices with values for the Fc and C3b indices in BHV-1-infected AM decreasing from 81 to 49 and from 47 to 8, respectively, and those for the PI-3 virus-infected AM from 79 to 51 and from 46 to 15, respectively. The binding indices of virus-infected AM increased with the addition of viral lavage fluids, but the only significant (P less than 0.05) increase was for C3b binding in PI-3 virus-infected cells, which increased from 33 to 56.(ABSTRACT TRUNCATED AT 250 WORDS)

[Maintenance and the clinical evaluation of periodontal patients in Konus-Telescope denture]

In order to assess by periodontal evaluation the changes that might occur with time in the abutment teeth and periodontal tissues when Konus-Telescope dentures are used as that final treatment of periodontal disease, the dentures (15 units) were placed in 13 patients with missing tooth and periodontal disease and findings at the time of denture placement and 30 months after the placement were compared. The number of cases that exhibited significant changes in hygiene level, tissue inflammation and periodontal pocket depth of the abutment teeth after 30 months was very small, while as many as 85.2% of the abutment teeth showed decrease in tooth mobility. Increase in tooth mobility was not detected in any of the cases. In addition, X-ray examination revealed tendencies toward improvement of the periodontal ligament and remission of alveolar bone resorption in many of the cases. These results suggest that Konus-Telescope denture is highly offers protection of the residual periodontal tissues through its secondary splint action.

[Childhood Ki-1 lymphoma complicated with multiple bone destruction]

A 4-year-old girl was admitted because of fever, swelling of left chest wall and left axillary lymphadenopathy. Chest XP revealed left pleural effusion. Ga-scintigram showed multiple accumulation in skull, left ribs and iliac bone. A diagnosis of childhood Ki-1 lymphoma was made from the pathological findings of tumor in the skull. Immunopathological study revealed that the neoplastic cells were CD8 positive (suppressor phenotype).

[Drug-protein binding in elderly subjects]

It is important to know the magnitude of serum-protein binding of drug dynamics in vivo. The authors investigated the effects of a variety of serum free fatty acids in elderly subjects. Serum albumin levels and ceftezole (CTZ)-protein binding in elderly subjects were lower than in younger subjects. No significant difference was noted between the two groups in regard to total free fatty acid (T-FFA) level. However, compared with younger subjects, palmitolic and oleic acid were higher and myristic and linoleic acid were lower in elderly subjects, suggesting that free fatty acid (FFA) undergoes qualitative changes due to ageing. In elderly subjects CTZ-binding correlated negatively with T-FFA, oleic acid and linoleic acid, but positively with stearic acid. Oleic acid decreased CTZ-protein binding. This decrease was higher than that due to decreased albumin levels in elderly subjects with albumin levels less than 4.0 g/dl. These findings indicated that reduced protein binding in elderly subjects is due to decreased serum albumin and changes in FFA constitution with ageing. Therefore it was suggested that drug-albumin binding may change due to the competitive action of albumin sites, and albumin-drug binding capacity. Since drug-protein binding capacity seriously affect metabolism, excretion, efficacy and side effects due to the presence of free drugs, these aspects require further investigation in elderly subjects.

Survival rate in children with fulminant hepatitis improved by a combination of twice daily plasmapheresis and intensive conservative therapy

Six of seven children with fulminant hepatitis (FH) were treated with a combination of twice daily plasmapheresis and intensive conservative therapy including special amino acid solution, glucagon-insulin therapy, dexamethasone, and so on. The remaining child was treated with intensive conservative therapy only because his condition was not so severe, in spite of being diagnosed as having fulminant hepatitis. Although five patients with biopsy-documented bridging hepatic necrosis or confluent hepatic necrosis in the acute phase made recoveries, the remaining two with massive hepatic necrosis died (the overall survival rate was 71%). The prognostic factors were considered to be the degree and pattern of liver cell necrosis, the degree of coma, and the etiology. The combination of twice daily plasmapheresis and intensive conservative therapy was effective for these pediatric patients with fulminant hepatitis, except those with massive hepatic necrosis.

A case of multiple arteriovenous malformations and diffuse venous abnormalities with facial port-wine stain

A case of left facial port-wine stain with right hemiparesis is reported. Radiologically, two arteriovenous malformations (AVM) and diffuse venous abnormalities were observed in the left hemisphere. AVM were seen in the basal ganglia. One was fed by a perforating artery from the MCA and drained into the superior petrosal sinus, and the other was fed by a perforating artery from the basilar artery and drained through the vein of Rosenthal into an extremely dilated vein of Galen. Venous abnormalities were obstruction and a decrease in the superficial cortical veins, as well as the formation of collateral veins in both the cortex and white matter. This case resembles Sturge-Weber syndrome (SWS), but there were no signs of leptomeningeal angiomatosis or venous angioma. We have been unable to find any case reports on SWS with AVM or AVM with diffuse venous abnormalities. We discuss the differences between our case and SWS.

The effects of hepatitis B vaccination on infants born to carriers without HBe antigenemia

A retrospective study on fifty-three patients born to hepatitis B surface antigen (HBs antigen) positive mothers was carried out. Among 17 patients born to hepatitis B e antigen (HBe antigen) negative mothers, six patients received hepatitis B(HB) vaccination and eleven did not. None of the six patients who had received HB vaccination showed seroconversion, while six of the 11 patients (54.5%) without HB vaccination did show seroconversion. There was no definite correlation between the frequency of seroconversion and the administration of HB immune globulin (HBIG). HB vaccination alone may be sufficient to protect infants born to HBe antigen negative mothers from HB viral infection.

Ultrasonography for the diagnosis of adenomyosis

An accurate preoperative diagnosis of uterine adenomyosis is often difficult. We reviewed our experience with ultrasound evaluation of this pathological entity. Patients with histologically proven adenomyosis were studied to determine the usefulness of ultrasound for the preoperative diagnosis of this entity. In patients with adenomyosis, variable ultrasound patterns are seen, namely, enlargement of the uterus, irregular vesicular spaces within the myometrium, and an acoustically enhanced posterior wall of the uterus. However, leiomyoma had a similar echopattern. Based on five cases of histologically extensive adenomyoasis, an accurate diagnosis of adenomyosis proved feasible when ultrasonography showed all three ultrasonic patterns mentioned above, associated with a retroverted uterus or possible adhesions between the uterus and structures in close proximity, nodule or outgrowth in the region of the uterosacral ligaments or in combination, as frequently found in conjunction with external endometriosis. The ultrasonographical demonstration of endometrial cyst of the ovary may contribute to an accurate diagnosis of adenomyosis.

Primary non-Hodgkin's lymphoma of the brain. A review

We have reported 14 primary non-Hodgkin's lymphomas of the brain seen in Calgary and Edmonton, Alberta, between 1975 and 1983. Eleven patients had histiocytic lymphoma while the remaining 3 were lymphocytic. The clinical presentations were extremely variable, with increased intracranial pressure (60%) and focal neurological deficits (60%) being most common. The most frequent appearance on computed tomographic scan was a hyperdense lesion of the cerebrum (44%); four cases had multifocal lesions. All patients had subtotal resection of the tumor. Two patients had surgery only and their mean survival was 3.5 months. Ten patients received whole brain irradiation, with 2 patients receiving a boost to the primary tumor site as well. The mean survival was 24.7 months. Two patients received chemotherapy in addition to radiotherapy and their mean survival was 20.0 months. Three of the 14 patients have had an inordinately long disease-free survival of 64, 75, and 80 months from the time of diagnosis.

A case report of a patient with retinoblastoma and chromosome 13q deletion: assignment of a new gene (gene for LCP1) on human chromosome 13

Retinoblastoma (Rb) occurs in hereditary, non-hereditary, and chromosomal deletion forms and the locus for the Rb gene (Rb-1) is closely linked to the locus for esterase D (ESD) assigned to the chromosome 13q14.11. We describe a patient who was predicted to have Rb from the genetic analysis of the chromosome and ESD phenotype. Furthermore, the gene for lymphocyte cytosol polypeptide with molecular weight of 64,000 (LCP1: McKusick catalogue No. 15343, 1983) was assigned to chromosome 13 by deletion mapping. A 3-month-old female had many characteristics of chromosome 13q-syndrome, including dolichocephaly, epicanthus, ptosis, depressed nasal bridge, micrognathia, short webbed neck, and short fifth fingers with clinodactyly and single crease. The karyotype of the patient was 46,XX,del(13) (q14.1-q32), though both the parents had normal karyotypes. As expected, the phenotype of ESD derived from one of the parents, the father in this case, was not detected in peripheral blood lymphocytes by two-dimensional gel electrophoresis (two-DE), indicating that ESD from the father was deleted in the abnormal chromosome 13. The possibility of paternity was calculated to be 0.996 based on the data using 22 genetic markers. Bilateral retinoblastomas could be diagnosed by ophthalmologic examinations before the manifestation of any clinical signs of the tumor and immediately intensive care was taken. In addition, the phenotype of LCP1 derived from the father was not expressed in the lymphocyte proteins from the patient. These data indicate that the gene for LCP1 (LCP1) is located in the region q14.1-q32 of chromosome 13 and may be a useful genetic marker for preclinical diagnosis of Rb.

Anorexia nervosa precipitated by a prepubertal pyometra

A severe pyometra was found in a typical case of anorexia nervosa, with the latter illness apparently precipitated by the former. Compulsory alimentation before and after operation brought some weight gain as well as reversal of dilated cerebral sulci and hypothyroidism, though hypothalamo-pituitary dysfunction persisted.