The excretion of large vitamin C loads in young and elderly subjects: an ascorbic acid tolerance test

An ascorbic acid tolerance test is described for assessing vitamin C status. The test is simple to administer and suitable for elderly patients. It involves giving an oral load of 1 g ascorbic acid in water and then measuring urinary excretion of vitamin C over the next 6 h. The excretion pattern at dosing has been studied in ten young subjects. The result of the ascorbic acid tolerance test in these young subjects was significantly different after supplementation with 1 g ascorbic acid daily for 1 month. Two series of elderly patients were also studied with the ascorbic acid tolerance test. They had low initial plasma ascorbic acid levels and much less vitamin C was excreted in the urine after dosing. Seven of these elderly patients were then supplemented with 1 g ascorbic acid for 1 month. After supplementation the initial plasma levels and their response to the ascorbic acid tolerance test became similar to that seen in younger subjects.

Kidney transplant recipients with long incubation-positive antiglobulin-negative T cell crossmatches

Low-affinity, cold-reactive antibodies easily removed by washing were not detected by the antiglobulin technique but killed T lymphocytes when washing was omitted, incubation was prolonged, and cytotoxic tests were incubated at room temperature or at 4 degrees C. These antibodies were present in approximately 25% of sera from dialysis patients. Only a subset of such sera (22%) reacted with autologous lymphocytes. The majority (86%) appeared to detect non-HLA antigens. A small number (14%) detected class I HLA antigens. Two patients transplanted with antiglobulin-negative, T-warm-negative crossmatch results, but positive cytotoxicity after a 2-hr incubation without washing, rapidly lost their grafts (less than 1 month) due to rejection. Their sera contained antibodies against non-HLA alloantigens expressed on lymphocytes and platelets, but not on granulocytes or erythrocytes. Two other patients with positive autoantibody tests exhibiting similar crossmatches with the current serum were transplanted recently. Both of them retain their grafts with good function at one month. In two other cases, the recipients were unreactive against the donor in current serum but displayed an antiglobulin-negative, 2-hr cytotoxicity-positive pattern in a previously drawn serum specimen. One patient continues to have stable renal function after 10 months. The other patient lost the transplant as a result of renal artery thrombus thought not to be immunologic in origin. Work is continuing to define the specificity and determine the clinical relevance of such cold-reactive antibodies.

Human liver N-acetylglucosamine-6-sulphate sulphatase. Catalytic properties

Kinetic parameters (Km and kcat.) of the two major forms (A and B) and a minor form (C) of human liver N-acetylglucosamine-6-sulphate sulphatase [Freeman, Clements & Hopwood (1987) Biochem. J. 246, 347-354] were determined with a variety of substrates matching structural aspects of the physiological substrates in vivo, namely heparin, heparan sulphate and keratan sulphate. Enzyme activity is highly specific towards glucosamine 6-sulphate or glucose 6-sulphate residues. More structurally complex substrates, in which several aspects of the aglycone structure of the natural substrate were maintained, are hydrolysed with catalytic efficiencies up to 3900 times above that observed for the monosaccharide substrate N-acetylglucosamine 6-sulphate. Forms A and B both desulphate substrates derived from keratan sulphate and heparin. Aglycone structures that influence substrate binding and/or enzyme activity were penultimate-residue 6-carboxy and 2-sulphate ester groups for heparin-derived substrates and penultimate-residue 6-sulphate ester groups for keratan sulphate-derived substrates. The 4-hydroxy group of the N-acetylglucosamine 6-sulphate or the 2-sulphaminoglucosamine 6-sulphate under enzymic attack is involved in the catalytic mechanism. The presence of a 2-amino group in place of a 2-acetamido or a 2-sulphoamino group considerably decreases the catalytic efficiency of the sulphatase, particularly in the absence of a penultimate-aglycone-residue 6-carboxy group. Both forms A and B are exo-enzymes, since activity towards internal sulphate ester bonds was not observed. The effect of incubation pH on enzyme activity towards the variety of substrates evaluated was complex and dependent on substrate aglycone structure. The presence of aglycone 2-sulphate ester, 6-carboxy group and 6-sulphate ester groups on the glucosamine 6-sulphate residue under attack considerably affects the pH response. Sulphate and phosphate ions are potent inhibitors of enzyme activity.

Human liver N-acetylglucosamine-6-sulphate sulphatase. Purification and characterization

Human N-acetylglucosamine-6-sulphate sulphatase was purified at least 50,000-fold to homogeneity in 78% yield from liver with a simple three-step four-column procedure, which consists of a concanavalin A-Sepharose/Blue A-agarose coupled step, chromatofocusing and Cu2+-chelating Sepharose chromatography. In all, four forms were isolated and partially characterized. Forms A and B, both with a pI greater than 9.5 and representing 30% and 60% respectively of the recovered enzyme activity, were separated by hydroxyapatite chromatography of the enzyme preparation obtained from the Cu2+-chelating Sepharose step. Both forms A and B had native molecular masses of 75 kDa. When analysed by SDS/polyacrylamide-gel electrophoresis, form A consists of a single polypeptide of molecular mass 78 kDa, whereas form B contained 48 kDa and 32 kDa polypeptide subunits. Neither form A nor form B was taken up from the culture medium into cultured human skin fibroblasts. The two other forms (C and D), with pI values of 5.8 and 5.4 respectively, represented approx. 7% and 3% of the total recovered enzyme activity. The native molecular masses of forms C and D were 94 kDa and approx. 75 kDa respectively. Form C contained three polypeptides with molecular masses of 48, 45 and 32 kDa. N-Acetylglucosamine-6-sulphate sulphatase activity was measured with a radiolabelled disaccharide substrate derived from heparin. The development of this substrate enabled the isolation and characterization of N-acetylglucosamine-6-sulphate sulphatase to proceed efficiently. Forms A, B and C had pH optima of 5.0, Km values of 11.7, 14.2 and 11.1 microM respectively and Vmax. values of 105, 60 and 53 nmol/min per mg of protein respectively. The molecular basis of the multiple forms of this sulphatase is not known. It is postulated that the differences in structure and properties of the four enzyme forms are due to differences in the state of processing of a large subunit.

Human liver sulphamate sulphohydrolase. Determinations of native protein and subunit Mr values and influence of substrate agylcone structure on catalytic properties

Human sulphamate sulphohydrolase was purified at least 20,000-fold to homogeneity from liver with a three-step four-column procedure, which consisted of a concanavalin A-Sepharose/Blue A agarose coupled step, and Bio-Gel HT step and then a CM-Sepharose step. The procedure was also used to purify enzyme from kidney and placenta. The subunit Mr of liver, kidney and placenta sulphamate sulphohydrolase was assessed to be 56,000 by using SDS/polacrylamide-gel electrophoresis. The native protein Mr of enzyme from all three tissue sources was assessed by gel-permeation chromatography to be approx. 120,000 on Sephacryl S-300 and 100,000 on Fractogel TSK. It is probable that the native enzyme results from dimerization of subunits. Kinetic parameters (km and kcat.) of human liver sulphamate sulphohydrolase were determined with a variety of substrates matching structural aspects of the physiological substrates in vivo, namely heparin and heparan sulphate. More structurally complex substrates, in which several aspects of the aglycone structure of the natural substrate were maintained, are turned over up to 372000 times faster than the monosaccharide substrate 2-sulphaminoglucosamine. Aglycone structures that influence substrate binding and/or enzyme activity were penultimate-residue C-6 carboxy and C-2 sulphate ester groups and a post-penultimate 2-sulphaminoglucosamine residue. The C-4 hydroxy group of the 2-sulphaminoglucosamine under enzymic attack is involved in binding of substrate to enzyme. The presence of C-6 sulphate ester on the non-reducing end 2-sulphaminoglucosamine stimulates sulphamate bond hydrolysis and substrate affinity if the adjacent monosaccharide residue is idose or 2-sulphoidose, but strongly inhibits hydrolysis if the adjacent monosaccharide residue is iduronic acid. Sulphamate sulphohydrolase is an exoenzyme, since activity toward internal sulphamate bonds was not detected. The effect of incubation pH on enzyme activity towards the variety of substrates evaluated was complex and dependent on substrate aglycone structure. The presence of aglycone C-2 sulphate ester and aglycone C-6 carboxy groups and C-6 sulphate ester groups on the 2-sulphaminoglucosamine residue under attack considerably affect the pH response. Structurally complex substrates had two pH optima. Incubation temperature and buffer ionic strength markedly influenced pH optima and enzyme activity. Cu2+ and SO4(2-)ions are potent inhibitors of enzyme activity.

The stability of Chemstrip bG used in conjunction with AccuChek bG

Reacted Chemstrip bGs were 1) stored in the original desiccated vial, 2) covered with white paper, or 3) left exposed on a counter, and were read at intervals of 10 hours, 1 day, 2, 3, 5, 7, 10, 14, and 21 days with AccuChek bG. Blank strips stored under the same conditions were used to calibrate the AccuChek bG. Blood glucose samples ranged from 60 to 400 mg/dl and read within 10 % of the original glucose con centration after 5 days. The strips remained within 79-100% of the initial value for 3 weeks, depending upon the blood glucose range. The find ings of this study are consistent with the manufacturer's claim that developed strips are stable for 7 days up to 320 mg/dl and for 4 days above 320 mg/dl when stored as recommended.

Local renal graft irradiation in children

Between 1974-1979, 64 renal cadaveric transplants were performed in 54 pediatric recipients at our institution. Forty eight of these 64 transplants experienced at least one episode of acute rejection. These patients were divided in two equal groups including 24 transplants in 21 recipients, one group treated with chemical immunosuppression alone, the other group treated by chemical immunosuppression and radiotherapy. Kidney survival at 2 years was 54.1% (13/24) in the control group treated by chemical immunosuppression alone. In the group treated by radiotherapy and immunosuppression, kidney survival after 2 years gave a success rate of 45.8% (11/24). Thus, it would appear that addition of radiotherapy to standard immunosuppressive treatment exerted no beneficial long term effect in acutely rejected renal transplants. In view of the disappointing results obtained with radiotherapy, it is felt that this mode of treatment should be restricted to use in particular circumstances as a temporary means of immunosuppression where systemic immunosuppression is hazardous.

Psychotherapy for bulimia: a controlled study

A psychotherapy study for bulimia is described. The preliminary results of a random allocation control trial comparing cognitive behaviour therapy, behaviour therapy and group psychotherapy with a waiting list control are presented. The results of the first 60 subjects in active treatment are shown. They indicate that all three treatments are effective in dramatically reducing the behavioural symptoms of the bulimia syndrome. There is evidence that cognitive therapy has a greater effect on symptoms of depression and self-esteem. No evidence is yet available on the longterm outcome of the three treatments.

Intracranial ependymomas and ependymoblastomas

Nineteen cases of intracranial ependymal tumors were reviewed to examine the prognostic factors influencing survival of the patients with this disease. The two most important predictive factors in relation to survival status were a histologic grade of tumors and a presence of hydrocephalus. The clinicopathological correlation in this study has supported the view of two distinct ependymal tumors; more curable ependymomas and highly malignant ependymoblastomas .

Cellular location of N-acetyltransfer activities toward glucosamine and glucosamine-6-phosphate in cultured human skin fibroblasts

The intracellular location in normal human cultured skin fibroblasts of the N-acetyltransferase activities that transfer the acetyl group from acetyl-CoA to the 2-amino group of glucosamine and glucosamine-6-phosphate have been investigated. Organelles have been separated using a combination of differential centrifugation and free flow electrophoresis. The intracellular distribution of the enzyme involved in the N-acetyltransfer to glucosamine and an alpha-glucosaminide disaccharide indicated that this enzyme activity concentrates mainly with lysosomal organelles whereas the activity associated with N-acetyltransferase to glucosamine-6-phosphate is non-lysosomal. It is proposed that acetyl-CoA: alpha-glucosaminide N-acetyltransferase may be used as a convenient enzyme marker of lysosomal organelle membranes.

Acetyl CoA:alpha-glucosaminide N-acetyl transferase: partial purification from human liver

The lysosomal enzyme acetyl CoA:alpha-glucosaminide N-acetyltransferase (GNAT) was shown to be an integral membrane protein requiring high concentrations of the detergent Triton X-100 for maximal solubilization. Using a concentration dependent Triton X-100 solubilization procedure and Concanavalin A-Sepharose affinity chromatography, GNAT was purified 50-fold with a yield of 45%. GNAT activity was separated from N-acetyltransferase activity toward glucosamine 6-phosphate, an alternative non-lysosomal pathway for glucosamine metabolism. GNAT was different from other lysosomal enzymes which bound to Concanavalin A-Sepharose in that both alpha-methylmannoside and Triton X-100 were required for elution of enzyme activity. GNAT activity, which bound to Concanavalin A-Sepharose, required at least one other component which did not bind for maximal expression of enzyme activity and for storage stability. Phospholipids and glycolipids, such as phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, sphingomyelin and gangliosides, and bovine serum albumin allowed expression of enzyme activity and storage stability similar to the component(s) which did not bind to Concanavalin A-Sepharose.

Phenytoin II: in vitro-in vivo bioequivalence standard for 100-mg phenytoin sodium capsules

A bioequivalence study was undertaken using an oral solution, a fast-dissolving capsule and a slow-dissolving phenytoin sodium capsule. The AUC, tmax and Cmax correlated with in vitro dissolution data. The results of the present studies substantiate the presence of two types of phenytoin sodium products on the market. On the basis of these studies, in vitro specifications for fast- and slow-dissolving phenytoin sodium capsules as well as the in vivo bioequivalence requirements for these two types of products are recommended.

Induction of complement receptor expression in cell lines derived from human undifferentiated lymphomas. II. Characterization of the induced complement receptors and demonstration of the simultaneous induction of EBV receptor

We have studied the specificity of complement receptors induced by theophylline in 2 cell lines derived from undifferentiated lymphomas, one of Burkitt's type, and compared it to that of complement receptors in other cell types. Both C3b and C3d receptors were induced. The induced C3b receptor differed from the C3b receptor of mature normal lymphocytes, polymorphonuclear leukocytes and the cells of a nodular lymphoma in 2 respects. Firstly, it bound C3b much less avidly (by a factor of several hundred-fold) and secondly, we were unable to demonstrate C4b binding. EBV receptors were induced at the same time as complement receptors, and permitted the conversion of a greater fraction of cells to EBNA positivity after experimental infection with EBV. The induction of receptors was not associated with a change in the fluidity of the plasma membranes and our data do not favor a different orientation of induced receptors within the membrane as compared to receptors of other cell types--a potential explanation for the different specificities. Our findings are consistent with the possibility that the complement receptors of lymphocyte precursors differ from these of mature lymphocytes.

Induction of complement receptor expression in cell lines derived from human undifferentiated lymphomas. II. Characterization of the induced complement receptors and demonstration of the simultaneous induction of EBV receptor

We have studied the specificity of complement receptors induced by theophylline in 2 cell lines derived from undifferentiated lymphomas, one of Burkitt's type, and compared it to that of complement receptors in other cell types. Both C3b and C3d receptors were induced. The induced C3b receptor differed from the C3b receptor of mature normal lymphocytes, polymorphonuclear leukocytes and the cells of a nodular lymphoma in 2 respects. Firstly, it bound C3b much less avidly (by a factor of several hundred-fold) and secondly, we were unable to demonstrate C4b binding. EBV receptors were induced at the same time as complement receptors, and permitted the conversion of a greater fraction of cells to EBNA positivity after experimental infection with EBV. The induction of receptors was not associated with a change in the fluidity of the plasma membranes and our data do not favor a different orientation of induced receptors within the membrane as compared to receptors of other cell types--a potential explanation for the different specificities. Our findings are consistent with the possibility that the complement receptors of lymphocyte precursors differ from these of mature lymphocytes.

Effect of nerve activity on transport of nerve growth factor and dopamine beta-hydroxylase antibodies in sympathetic neurones

The effect of nerve activity on the uptake and retrograde transport of nerve growth factor (NGF) and dopamine beta-hydroxylase (DBH) antibodies was studied by injecting 125I-labelled NGF and anti-DBH into the anterior eye chamber of guinea-pigs. Decentralization of the ipsilateral superior cervical ganglion (SCG) had no significant effect on the retrograde transport of either NGF or anti-DBH. Phenoxybenzamine produced a 50% increase in anti-DBH but not NGF accumulation and this effect was prevented by prior decentralization. This demonstrates that NGF is taken up independently of the retrieval of synaptic vesicle components.

Low-back pain following multiple lumbar spine procedures. Failure of initial selection?

A retrospective review was made of 30 patients who had failed multiple traditional surgical procedures for low-back pain, sciatic pain, or both. The most common cause of the poor results appeared to be failure of initial selection, even though all patients appeared to meet traditional indications for operative intervention. Psychosocial problems (eg, drug abuse, alcoholism, marital discord, personality disturbances) were prevalent, but were not initially recognized. Thoughtful assessment of patients being considered for initial lumbar spine surgery, which includes objective psychological testing, may reduce the incidence of unsuccessful lumbar spine surgery.

Single case study. Complementary effects of phenelzine and psychotherapy in long term treatment of depression

A case report is described wherein the monoamine oxidase inhibitor phenelzine was administered for 10 months at different doses. Drug treatment in the initial part of the study was double blind. Weekly psychotherapy was instituted at the point of symptomatic recovery. At a reduced dose, in month 3, the patient experienced a relapse in depression. While platelet monoamine oxidase inhibition was greater than 80 per cent the patient was well, but at the point of relapse, inhibition was 14 per cent. Clinical ratings at relapse (Beck and SCL-90 scales) revealed greater readiness by the patient to report psychological discomfort compared with the original interview. The combined effects of psychotherapy and pharmacotherapy were felt to be responsible for this change. However, psychotherapy in this form and duration did not prevent relapse, which depended upon maintaining an adequate dose of phenelzine.

DISTRIBUTION AND DIAGNOSIS OF DIROFILARIASIS AND TOXOCARIASIS IN AUSTRALIA

The prevalence of Dirofilaria immitis infection in dogs continues to increase in the temperate east coast zone of Australia (and is extending further south into New South Wales and Victoria). However, the infection rate has not changed in the tropics over the past 10 years where it would appear that a maximum infection rate of 90% occurs in a given Australian dog population. Twelve percent of Brisbane dogs had occult dirofilariasis and it is suggested that the proportion of occult infections was probably higher in the tropics. Dogs of all breeds appear equally susceptible to D. immitis with infection being more common in older male dogs. The level of microfilaraemia was, occasionally, proportional to the number of heartwprms per dog. Toxocara canis was present in about 75% of dogs from all areas studied except in Central Australia where the level of infection was much lower. Immunodiagnosis of D. immitis and T. canis with high specificity and sensitivity was achieved by cyanogen bromide indirect fluorescent antibody and cell-mediated immunity tests using parasite antigens purified by affinity chromatography. These tests enabled occult dirofilariasis to be differentiated from unrelated canine cardiac and pulmonary failure. Such immunodiagnosis can aid in the early diagnosis of dirofilariasis particularly in situations where no circulating microfilariae can be detected. The prevalence of serum antibody in man to purified Dirofilaria and Toxocara antigens was proportional to the incidence of respective canine infections at each location.

Experts exchange views on grievance procedures in hospitals

Four participants in a roundtable discussion examined the specific grievance procedures of a nonunionized, not-for-profit, medium-sized hospital and of a partially unionized, not-for-profit, large teaching hospital. In doing so, they also raised questions, considerations, and guidelines that may be of interest to hospitals that already have or that are planning grievance procedures.

Treatment of intestinal amoebiasis and giardiasis; efficacy of metronidazole and tinidazole compared

Aboriginal children who were aged from six to nine years and living in Cherbourg Community were treated for Giardia Lamblia and Entamoeba histolytica infection with either the manufacturer's recommended dose of metronidazole (Flagyl) or with tinidazole (Fasigyn), at two-dose levels. Tinidazole successfully cleared both protozoans from stools, a single dose being as effective as the longer regimens which were studied. The obvious advantage of single-dose administration is that it should permit more effective treatment of these intestinal parasites, especially in Aboriginal populations.

A possible role for insulin in the altered capability for hepatic enzyme adaptation during aging

The pattern of change in the concentration of immunoreactive insulin in portal vein blood during a 7-hour period following intragastric administration of glucose to fasted, male Sprague-Dawley rats is modified both in magnitude and time course of response as rat age increases from 2- to 24-months. This alteration in the control of insulin levels probably is not the consequence of modifications in the availability of administered glucose to the pancreas. A similar modification in the control of insulin secretion also is evident when pancreatic islets isolated from fasted rat donors aged 2- to 24-months are perifused with glucose in vitro. This may represent the first demonstration of an altered response of aging animals which is expressed in the same way in an isolated in vitro system.

Using the MMPI 168 with medical inpatients

The potential utility of the MMPI 168 with two inpatient medical populations was explored in the present study. Correlations and clinically relevant comparisons suggested that the MMPI 168 predicted the standard MMPI with a high degree of accuracy.

Sonography of the Page kidney

We used sonography to investigate 3 patients with hypertension owing to a Page kidney phenomenon. In 2 cases a perinephric cystic collection was compressing the kidney, while in 1 case there was a large perinephric organized hematoma. When a Page kidney is suspected in a hypertensive patient sonography is a reasonable next step in the evaluation, after the excretory urogram, and may obviate the need for angiography.

The use of the Minnesota Multiphasic Personality Inventory with low back pain patients

The MMPI was administered to 36 male low back pain patients at the Seattle Veterans Administration Hospital. The patients were divided into three groups of 12 each. The organic group contained patients who had an organic basis for their pain. The functional group contained patients who had no organic basis for their pain. The mixed group contained patients who had some organic basis for their pain, but one that was thought to be insufficient to account for the pain they were reporting. The mixed and functional groups differed significantly from the organic group on the Hs, Hy, Pt, Sc, Hy-O, D-O, and DOR scales. The mixed and functional groups differ significantly from each other only on the Hy-O scale. The special low back pain scales of Lb and DOR were found to have little utility when used separately. When used in conjunction, however, the scales discriminated correctly 75% of the time.

Management of postoperative renal hemorrhage by transcatheter embolization

A patient with uncontrollable postoperative renal hemorrhage was successfully treated by sub-selective injection of autologous clot into the renal artery. Followup arteriography 10 days later revealed persistent occlusion of the bleeding vessel with recanalization of all other vessels. This method is an effective alternative to an operation in cases of renal hemorrhage of diverse etiology not responsive to conservative management.

Malignant pheochromocytoma of the bladder: the late development of renal cell carcinoma

A case of malignant pheochromocytoma of the bladder associated with renal cell carcinoma is described. The necessity for long-term followup in such cases is stressed. This case provides further documentation of the association of pheochromocytoma with renal cell carcinoma, an association which may occur more frequently than would be dictated by chance alone. It is suggested that these cases may represent von Hippel-Lindau disease with incomplete penetrance.

Preliminary human trial of a new male sterilization procedure: vas sclerosing

A new procedure developed in animals has been applied to produce male human sterilization. This involves the percutaneous injection of an ethanol and formaldehyde solution into the vasa deferentia. An initial clinical trial of eight human volunteers indicates that this is an effective method of producing male sterilization.