IgG rheumatoid factor-secreting lymphocytes in rheumatoid arthritis: evaluation of a haemolytic plaque-forming cell technique

A haemolytic plaque-forming cell (PFC) assay detecting human B lymphocytes secreting IgG rheumatoid factor (RF) was established using sheep erythrocytes (SRBC) sensitized with rabbit IgG, developing rabbit anti-human IgG, and complement. IgG-RF PFC were only demonstrated with IgG-depleted guinea-pig serum as the source of complement. Cells spontaneously secreting IgG-RF were found among synovial fluid mononuclear cells (mean, 134/10(6)) and synovial tissue mononuclear cells (mean, 1775/10(6)) from patients with rheumatoid arthritis, whereas few were recorded among blood lymphocytes (mean, 3/10(6)). The experiments revealed that the RF-IgG PFC were protein-synthesizing B lymphocytes. The antibody specificity of the secreted IgF-RF was verified by the inhibitory effect of exogenous human and rabbit IgG on PFC formation.

Suppression of B lymphocytes in mature newborn infants

The ability of cord blood lymphocytes to secrete immunoglobulins during in vitro culture was investigated by means of a reverse hemolytic plaque forming cell (PFC) assay. Mononuclear cord blood cells did not differentiate into immunoglobulin-secreting cells after stimulation with the polyclonal B lymphocyte activator pokeweed mitogen (PWM), contrary to the findings in normal adults. Mononuclear cord blood cells were then separated into T-enriched and T-depleted blood lymphocyte subsets. When these were co-cultured, the PWM-induced immunoglobulin secretion was still low; following irradiation of the T-enriched cells, the numbers of IgM-PFC but not of IgG- or IgA-PFC increased considerably. The effect of irradiation of the T-enriched cells on the PWM-induced IgM response was dose-dependent, with maximal effect at 2500 rad. It is concluded that the low PWM responses obtained using cord blood lymphocytes are in part due to suppression by radiosensitive T suppressor cells. Following removal of this suppression by means of irradiation, B lymphocytes can be induced to secrete IgM, but not IgG or IgA.

Effects of cyclosporin A (CyA) and methylprednisolone (MP) on the immune response. II. Further studies of the monocyte - T cell interactions leading to lymphokine production

The immunosuppressive drugs cyclosporin A (CyA) and methylprednisolone (MP) abolished the elaboration of the lymphokine leukocyte migration inhibitory factor (LIF) by mononuclear cells challenged by recall antigen. Suppression in both cases was reversible upon removal of the drugs, and participation of T suppressor cells of their mediators could not be demonstrated. The CyA-induced effect was exerted in the early stage of lymphocyte activation (less than 60 min), whereas MP still inhibited LIF release when added 60 min after the antigen. In contrast to earlier findings that the drugs failed to affect the release of T cell-activating factor (TAF) and lymphocyte-activating factor (LAF) from macrophages (M-phi's) stimulated by phorbol myristate acetate. MP (but not CyA) markedly reduced TAF production by M-phi's incubated with tuberculin. M-phireover, partially purified TAF and LAF both restored LIF production in the presence of CyA (but not MP), an effect not mimicked by the T cell product T cell growth factor. However, suppression by both drugs was abrogated by exogenous cGMP. Hence, CyA seems to obstruct the interaction between TAF/LAF and the immune T cell, whereas MP affects antigen-induced T cell activation at the Mo level as well as the level of lymphokine production and/or release. The effects of both drugs seem related to intracellular events involving cGMP.

Lack of evidence for granulocyte specific membrane-directed autoantibodies in neutropenic cases of rheumatoid arthritis and in autoimmune neutropenia

With the purpose of detecting granulocyte-specific membrane-directed autoantibodies, IgG was isolated from 14 patients with Felty's syndrome, from 5 patients with rheumatoid arthritis associated with neutropenia, and from 3 rheumatoid factor positive patients with autoimmune neutropenia. By means of indirect immunofluorescence suspensions of leukocytes from healthy controls were tested for their ability to bind whole IgG fractions or F(ab')2 fragments of IgG isolated from the neutropenic patients. By this method, whole IgG preparations from neutropenic patients and normal controls were invariably found to bind to the surface of granulocytes and a minor proportion of lymphocytes. In contrast. F(ab')2 fragments of IgG from the neutropenic patients failed to bind to the surface of granulocytes. Both whole IgG fractions and F(ab')2 fragments displayed displayed antinuclear antibody activity ruling out the possibility of loss of antibody reactivity during the preparation of F(ab')2 fragments. The neutropenia seen in rheumatoid arthritis with or without splenomegaly thus does not seem to be induced by granulocyte-specific membrane-directed IgG autoantibodies, but rather by a non-specific attachment of IgG most probably in immune complex bound form to Fc gamma receptors on neutrophils which thereby acquire surface properties facilitating removal from the circulating blood cell pool.

Secretion of IgM-rheumatoid factor and IgM by blood lymphocytes in rheumatoid arthritis

A direct plaque forming cell (PFC) assay for the detection of complement fixing IgM-rheumatoid factor (RF) secreting lymphocytes was evaluated. The specificity of the RF-PFC assay was demonstrated by the inhibitory action of exogenous human IgG. The sensitivity of the RF-PFC assay was similar to that of a reverse PFC assay detecting all cells secreting IgM (IgM-PFC). In blood from 75% of seropositive patients with rheumatoid arthritis (RA) RF-PFC were demonstrated, median value 6.8 (range: 0.4-1477) RF-PFC/10(6) mononuclear cells. Practically no RF-PFC were detected in seronegative RA patients and controls. Despite the fact that most IgM-RF undoubtedly is produced outside the blood, a positive correlation was found between the number of RF-PFC and the Waaler-Rose titer in serum. The number of circulating IgM secreting cells did not differ significantly between seropositive RA patients, seronegative RA patients and controls. Comparison of RF-PFC and IgM-PFC in seropositive patients revealed that in mean 7% of IgM-secreting cells in blood secrete IgM-RF.

The long-term clinical course of systemic lupus erythematosus in end-stage renal disease

In an attempt to define the long-term clinical course of systemic lupus erythematosus followed by end-stage renal disease, we studied 28 patients with lupus nephritis at Stanford University between January 1969 and December 1980. The clinical and serologic manifestations of both renal and nonrenal disease improved with long-term hemodialysis despite the withdrawal of immunosuppressive drugs in almost all the patients. Rehabilitation was excellent, and a return to normal physical activity was generally the rule. The mortality rate was low (6 of the 28 patients died), but death occurred primarily in patients receiving high doses of prednisone. Recovery from renal failure and discontinuation of dialysis were not rare (eight patients recovered) despite the reduction in immunosuppressive drugs. Renal transplantation was also well tolerated. We found the long-term clinical course of these patients to be comparable to that of patients with end-stage renal disease associated with disorders other than systemic lupus erythematosus.

Vitamin B12 binding proteins (transcobalamin and haptocorrin) in serum and synovial fluid of patients with rheumatoid arthritis and traumatic synovitis

The vitamin B12 (cobalamin) binding proteins, transcobalamin and haptocorrin, were measured in serum and synovial fluid of 12 patients with rheumatoid arthritis (RA) and 11 patients with traumatic synovitis (TS). Levels of both the cobalamin-binding proteins of synovial fluid were markedly elevated in RA compared with TS. In serum, the haptocorrin concentrations were significantly increased in RA vis-à-vis TS. In synovial fluid of RA patients, the transcobalamin and haptocorrin concentrations were positively correlated to the concentrations of macrophages and polymorphonuclear granulocytes, respectively. The demonstration of increased synovial fluid transcobalamin/total protein and haptocorrin/total protein ratios in RA vis-à-vis TS provides further evidence of a local production or liberation of the cobalamin-binding proteins in synovial fluid of patients with RA.

Intravenous radionuclide angioscintigraphy and computer tomography in cerebral arteriovenous malformations

In 25 patients with cerebral arteriovenous malformation (AVM) computer tomography (CT) was compared with dynamic and static intravenous radionuclide angioscintigraphy (99mTc-labelled red blood cells). The diagnosis was verified by arteriography performed 2-20 years prior to this study. Scintigrams and CT-scans were evaluated 'blindly' by independent observers after pooling of the patient studies with 20 and 20 control studies, respectively. Only images strictly characteristic of AVM were classified as positive. The nosographic sensitivity of both methods was about 70%, in a few patients they were supplementary. Neither CT nor scintigraphy were able to detect lesions of less than 2 cm diameter. The methods seem to be of equal and rather high specificity, and are both well suited as screening procedures. CT provides additional information as to other intracranial abnormalities. The screening method of first choice when AVM is suspected may be CT or angioscintigraphy, depending on availability of equipment and expertise.

Synovial fluid and blood monocyte influence on lymphocyte proliferation in rheumatoid arthritis and traumatic synovitis

The influence of synovial fluid and blood monocytes on autologous lymphocyte proliferation in vitro was investigated in patients with rheumatoid arthritis (RA) and traumatic synovitis (TS). In cultures stimulated with PHA, PWM and ConA, thymidine incorporation by RA blood mononuclear cells (BMC) increased considerably in most cases after addition of 10% or 30% synovial fluid monocytes and a similar effect was seen after stimulation with Candida extract or PPD. A comparable helper activity was observed after addition of synovial fluid monocytes to monocyte-depleted blood cells in RA. The augmenting effect of synovial fluid monocytes was likewise demonstrated in TS patients. Synovial fluid mononuclear cells (SMC) from RA and TS patients displayed low proliferative responses to PHA and ConA in comparison with BMC, while the responses to microbial antigens were similar or greater. The proliferative activity of SMC or of monocyte-depleted synovial fluid cells after polyclonal and antigenic stimulation was not affected by addition of blood monocytes. This was observed in both RA and TS patients. It is concluded that the regulatory properties of synovial fluid monocytes in RA and TS do not explain the low proliferative responses of SMC to polyclonal activators.

Immunosuppressive actions of gold salts

In rheumatoid arthritis both lymphocyte-mediated and antibody-mediated immune reactions are important for the inflammatory lesions. In vivo activated B lymphocytes/plasma cells, T lymphocytes and monocytes/macrophages (Mo) are intimately involved in the disease process. Several clinical observations suggest an immunosuppressive action of gold salts. In humans, gold salts interfere with a number of Mo functions in vitro, including cellular interactions between Mo and T lymphocytes. Some workers have shown that the activation of human T lymphocytes is inhibited by gold salts, most probably secondary to an inhibition of Mo-T cell cooperation. Recent experiments indicate that gold salts also affect the in vitro differentiation of human B lymphocytes in response to polyclonal activators. Both the gold atom and the SH group seem to be important for the immunosuppressive actions of gold salts.

Effect of cyclosporin A (CyA) on the immune response. CyA competitively inhibits the function of monocyte/macrophage-derived T-lymphocyte-activating factor(s)

The mechanism of action of the immunosuppressive drug, cyclosporin A (CyA), was analyzed with respect to antigen-induced production of the human lymphokine, leukocyte migration inhibitory factor (LIF). Mononuclear cells as well as purified T-cells did not elaborate LIF in the presence of pharmacological concentrations of CyA. CyA-induced immunosuppression was competitively reversed by addition of the partially purified monokines, T-cell-activating factor (TAF) and lymphocyte-activating factor (LAF). CyA did not affect T-cell priming with antigens. The drug failed to abolish LIF production if added 60 min after challenge of T-cells with recall antigen in the presence of TAF. Furthermore, addition of TAF within 15 min to CyA-treated T-cells resulted in unaltered LIF production. These results suggest that CyA suppresses the early stage of the immune response by competing with the function of TAF/LAF on the immune T-cell.

Induction and abrogation of suppressor cell function in humans: effect on B cell activation by different polyclonal activators

In a reverse plaque forming cell (PFC) assay, the effect of concanavalin A (Con-A)-induced suppressor cells on polyclonally activated B lymphocytes was studied. Differentiation to PFC, as induced by pokeweed mitogen (PWM), Staphylococcus aureus or Epstein-Barr virus (EBV) was in all cases suppressed by the addition of ConA-pretreated cells. The EBV-stimulated cells showed the smallest PFC response and appeared least amenable to suppression. IgA-secreting cells were less suppressible than IgM- and IgG-secreting cells regardless of the polyclonal B lymphocyte activator used. The suppressor cells were radiosensitive.

Influence of autologous monocytes on the pokeweed mitogen-induced generation of immunoglobulin-secreting cells in man

The regulatory influence of autologous blood monocytes on the PWM-induced generation of Ig-secreting cells was assessed using a reverse haemolytic plaque forming cell (PFC) assay. The PWM-induced PFC responses of monocyte-depleted cells were low or absent in most cases. Addition of 12-42% freshly isolated monocytes fully reconstituted the IgM-, IgG- and IgA-PFC responses. With more monocytes added, the PFC responses declined. Monocytes precultured for 48 h supported the PFC responses of monocyte-depleted cells less well and addition of monocytes stimulated with phorbol myristate acetate (PMA) did not increase the response. The low responses of monocyte-depleted cells co-cultured with precultured monocytes were not increased by addition of supernatant from monocyte cultures. The PFC responses of mononuclear cells induced by PWM were significantly inhibited by unstimulated precultured monocytes, and to a larger degree by PMA-treated monocytes, indicating the presence of suppressor cells among the precultured monocytes. The PWM-induced thymidine incorporation by monocyte-depleted cells with precultured monocytes added was only slightly lower than that obtained with freshly isolated monocytes added, suggesting that the suppressive role of precultured monocytes was not due to cytotoxicity.

Fate of [125I]insulin removed from the peritubular circulation of isolated perfused rat kidney

Although there is considerable evidence that insulin is removed from the peritubular circulation of the mammalian kidney, it is unclear whether binding to insulin-specific receptors is involved in this process, whether after peritubular removal the hormone is degraded to small fragments with release into the circulation, or whether it merely undergoes a minor modification with loss of immunoreactivity. We examined the metabolism of [125I]insulin removed from the peritubular circulation of the nonfiltering isolated perfused rat kidney and compared it to that of [125I]insulin metabolized by filtering isolated kidneys and kidney homogenates. The results indicate that after peritubular removal, a small amount of insulin is degraded to form low-molecular-weight products similar to those seen with filtering kidneys and kidney homogenates. However, most of the insulin removed from the peritubular circulation is processed either to nonimmunoreactive products of molecular weight similar to that of insulin or, to a lesser extent, to products of larger molecular weight. Both these products are also formed by filtering kidneys. In the filtering kidney, the products having molecular weight similar to that of insulin probably originate from the peritubular process, because it is unlikely that material of this size could be derived from the filtration-absorption pathway. Of particular note was the finding that [125I]insulin trapped in the peritubular compartment of nonfiltering kidneys was displaced severalfold more effectively by unlabeled insulin than by several peptide hormones (P less than 0.01); the latter were no more effective than vehicle alone. The findings suggest the presence of peritubular insulin-specific receptors.

Effects of cyclosporin A (CyA) and methylprednisolone (MP) on the immune response. I. T-cell-activating factor abrogates CyA- but not MP-induced suppression of antigen-induced lymphokine production

The influence of cyclosporin A (CyA) and methylprednisolone (MP) on the elaboration of the human lymphokine, leukocyte migration inhibitory factor (LIF) was investigated. Both CyA and MP at pharmacological concentrations inhibited the release of LIF from immune lymphocytes challenged by recall antigen. By contrast, the release of LIF in response to polyclonal activation by phytohaemagglutinin A was not affected by CyA or by MP. CyA and MP had no effect on the production of the monokine, T-lymphocyte-activating factor (TAF) by stimulated blood monocytes. However, addition of partially purified TAF to antigen-stimulated lymphocytes completely abrogated the inhibitory effect of CyA, but not that of MP. Thus, CyA and MP affect antigen-induced production of LIF by immune lymphocytes by different mechanisms.

Involvement of monokines in antigen- and lectin-induced human lymphokine production

To analyze the role of monocytes/macrophages (Mø's) in the activation of human lymphocytes, suspensions enriched in T cells and markedly depleted of Mø's were prepared. The Mø-depleted cells challenged by tuberculin did not elaborate the lymphokine, leukocyte migration inhibitory factor (LIF). This reduction in LIF production was negatively correlated to the proportion of residual Mø's being complete in the presence of less than 2% Mø's. In contrast, the LIF response to the polyclonal activator, phytohemagglutinin A, was unimpaired by Mø depletion. LIF production of the Mø-depleted cells could be fully reconstituted by addition of conditioned media obtained from Mø cultures, especially if stimulated by the Mø-activating agent, phorbol myristate acetate. This effect was dose-dependent and could be ascribed to molecules of molecular weights 80K and 12K, respectively.

High-affinity 86Rb-binding and structural changes in the alpha-subunit of Na+,K+-ATPase as detected by tryptic digestion and fluorescence analysis

High-affinity 86Rb-binding has been related to tryptic cleavage and fluorescence from intrinsic and extrinsic probes in order to examine the relationship of cation binding to structural transitions in the alpha-subunit of pure membrane-bound Na+,K+-ATPase from the outer renal medulla. Native Na+,K+-Atpase binds two Rb+ ions per alpha-subunit (12.3 nmol/mg protein) with high affinity (Kd = 7.5 microM) in 25 mM Tris-HCl, pH 7.5. Enzyme with one molecule of covalently attached fluorescein per alpha-subunit has the same capacity (12.8 nmol/mg protein) but a much lower affinity for Rb+ (Kd = 29.2 microM). The changes in conformational state of the protein are correlated with occupancy of the high-affinity sites for Rb+, also at concentrations of Rb+ below the Kd. Titration at varying ionic strength suggests that the E2-form is the relaxed or native conformation of the alpha-subunit. Changes in tryptic digestion pattern and in fluorescence are parallel events both in the conditions of the binding assay and at physiological ionic strength. Reversible blocking of sulfhydryl groups with Thimerosal (ethylmercurythiosalicylate) abolishes the fluorescence responses to K+ or Rb+ without affecting the capacity or the affinity for binding of 86Rb. The demonstration of high-affinity binding of Rb+ without coupling to a conformational change suggests that the E1-form of the protein exposes sites for tight binding of K+ or Rb+ at the cytoplasmic membrane surface.

Binding and degradation of insulin by isolated renal brush border membranes

Filtered proteins including insulin are absorbed in the proximal tubule by means of pinocytosis. The first step in this process is binding of the protein to brush border membrane. As it is not known whether absorption exhibits specificity, we set out to determine whether specific binding sites for insulin are present in brush border membranes. Rabbit-isolated brush border membranes were incubated with 125I-insulin and varying concentrations of cold insulin or other peptide hormones. Binding and degradation of 125I-insulin occurred in a time- and temperature-dependent manner. Native insulin competitively inhibited 125I-insulin binding, but calcitonin, arginine vasopressin, glucagon, and growth hormone (10(-6) M) were relatively ineffective. Nonspecific binding averaged one-third of the total radioactivity bound. Scatchard analysis of binding data revealed two classes of insulin receptors: high affinity, low capacity receptors and low affinity, high capacity receptors. Gel filtration analysis of 125I-insulin exposed to brush border membrane revealed the formation of low-molecular-weight products similar to that produced by intact kidneys. The degrading process exhibited some specificity, for cold insulin (10(-6) M) was more effective than calcitonin, vasopressin, glucagon, or growth hormone in inhibiting degradation (32% versus less than 13% inhibition; P less than 0.01). Whether this reflects inhibition of insulin specific binding before exposure to degradation or inhibition of specific enzymes is unclear. In summary, it appears that renal brush border membranes have a major insulin-specific receptor component that could potentially mediate tubular insulin absorption. In addition, there is a smaller nonspecific component that may also have the potential to mediate insulin absorption. Finally, it appears that brush border membranes have the ability to degrade insulin to low-molecular-weight products by a process that exhibits some specificity for insulin.

[Psychogenic visual disturbances in children and adults. Ophthalmological, neurological and psychodynamic findings]

In large series of ophthalmic patients there may occasionally be some in whom the reduction of visual acuity cannot be explained by organic findings. In such patients simulation is suspected. However, simulation is not the only cause of decreased visual acuity and a lack of organic pathologic findings. It is obvious that all efforts must be made to exclude organic changes as the cause of decreased visual acuity. With modern diagnostic modalities this is possible to a large extent. If there are no organic pathologic findings, a psychiatric exploration is indicated. In the eight patients presented in this paper the reduction of visual acuity was the expression of a psychologic conflict situation. The cases are described in detail and the difference between simulation and a psychogenic decrease of visual acuity is pointed out.

Production and secretion of immunoglobulins by in vitro-activated human B lymphocytes

Activation induced by pokeweed mitogen in cultures of mononuclear cells from human blood was followed sequentially by simultaneous quantitation of live cells, thymidine incorporation, cells displaying cytoplasmic, IgM, IgG, IgA or IgD, cells secreting IgM, IgG or IgA and cumulated IgM secretion. Maximal cellular activity was found after 7 days of cultures, with means of 16000 IgM-, 20700 IgG- and 9900 IgA-secreting cells per 10(6) originally cultured cells. The cumulated IgM secretion after 21 days of culture averaged 10400 ng per 10(6) originally cultured cells. A close correlation was found between the number of IgM-secreting cells and the cumulated IgM secretion.

Effect of acetylsalicylic acid on renal function in systemic lupus erythematosus

Glomerular filtration rate (GFR; 51Cr-EDTA clearance), serum creatinine concentration and urinary excretion of prostaglandins were measured in 8 patients with systemic lupus erythematosus (SLE) before and after 2 weeks of treatment with acetylsalicylic acid (ASA). ASA 65 mg/kg or up to 4 g/daily was given as a sustained release preparation. The serum salicylate concentration ranged from 0.3 to 1.6 mmol/l. Serum creatinine after 1 and 2 weeks and GFR after 2 weeks of ASA treatment showed no significant changes. There was a clearcut decrease in urinary excretion of prostaglandins PGE2 and PGF2 alpha, by 44% and 50%, respectively. It is concluded that therapeutic doses of ASA do not cause deterioration of GFR in patients with SLE and normal or moderately reduced renal function.

Functional characteristics of synovial fluid and blood mononuclear cells in rheumatoid arthritis and traumatic synovitis

The activity of blood mononuclear cells (BMC) and synovial fluid mononuclear cells (SMC) from patients with rheumatoid arthritis (RA) and traumatic synovitis (TS) was assessed by means of [14C]thymidine incorporation and production of leukocyte migration inhibitory factor (LIF). When compared with normal controls, spontaneous LIF production by BMC was found in 5 of 9 TS patients, whereas spontaneous LIF production by rheumatoid arthritis BMC and by SMC from both patient groups was infrequently seen. ConA-induced LIF production by BMC and SMC from both patient groups did not differ significantly from that of normal controls. Thymidine incorporation by unstimulated SMC and BMC was low in both patient groups. After stimulation with polyclonal activators, SMC showed significantly reduced proliferation in comparison with BMC, but the responses to microbial antigens were equal to or higher than those of BMC. The proliferative responses of stimulated SMC from TS patients were higher than the responses displayed by stimulated SMC from RA patients.

The effect of frusemide and piretanide on the renal clearance of gentamicin in man

1 Gentamicin alone (dose 1 mg/kg) or in combination with frusemide (dose 0.25 mg/kg) or piretanide (dose 0.1 mg/kg) was administered intravenously to six healthy male volunteers. 2 Blood samples were collected at various times for 24 h and urine for up to 48 h. 3 Both diuretics increased the renal clearance of gentamicin during the period of the diuresis, without influencing either the glomerular filtration rate or the distribution of the antibiotic. 4 The results are discussed in relation to gentamicin-induced nephrotoxicity.

State-trait anxiety and biofeedback mediated control of peripheral vasomotor responses

42 undergraduates completed the State-Trait Anxiety Inventory and then received biofeedback for increases in index finger-skin temperature. Subjects with high-trait anxiety increased their temperature significantly more than subjects with low-trait anxiety. No significant differences were found among state anxiety groups. The results supported the conclusion that predisposition to anxiety (trait), and not situational (state) anxiety, improves peripheral vasomotor control.

Possible role of histamine in rheumatoid arthritis. Treatment with cimetidine and mepyramine

Basophilocytes from patients with rheumatoid arthritis (RA) responded to leukocyte nuclei from normal persons with histamine release; a similar histamine release induced by the nuclear components RNA and DNA has been demonstrated previously. A role of histamine in RA is also supported by the findings of clinical improvement during treatment with H1 and H2 antihistamines in six of 12 patients with RA in active phase, whereas four showed definite deterioration.

[Morphological and functional findings in a family with aniridia (author's transl)]

The history of a family with aniridia (11 patients) is presented. Morphologically the following changes were found: Ptosis, microcornea, anterior embryotoxon, defects of the iris ranging from corectopia and coloboma to hypoplasia of the iris and clinical aniridia cataracts and hypoplasia of the fovea. Functionally there was reduced visual acuity (best vision 0.2), nystagmus and strabismus. Dark adaptation, electrooculogram, photopic and scotopic electroretinogram were within normal limits. The patients were found to have a red-green color vision deficiency, which was perhaps caused by foveal hypoplasia and nystagmus, and a trito defect which could not be explained.

Gentamicin-induced nephrotoxicity in mice: protection by loop diuretics

Gentamicin, at doses of 50 or 100 mg/kg body wt administered daily to healthy male MF1 mice by i.p. injection for either 7 or 10 days caused proximal tubular cell damage shown both by the urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) and by electron microscopy. The tubular damage was maximal at 7 days. Concomitant administration of any of 3 diuretics-frusemide, bumetanide or piretanide at 5,0.5 and 1 mg/kg body wt/day respectively-resulted in less tubular damage than that caused by gentamicin alone. This finding of protection by diuretics contrasts with those of previous studies of combination gentamicin-diuretic therapy.

Cimetidine-a clinical and pharmacokinetic study

1 The effect of six months therapy with cimetidine (800 mg or 1600 mg/day) and subsequent withdrawal was studied in 19 patients with duodenal ulceration. 2 The overall rates of healing were 63% and 79% of patients after 3 and after 6 months of treatment respectively. The longer course (6 months) or the higher dose (1600 mg) did not result in significantly increased rates of ulcer healing. 3 Abrupt withdrawal of cimetidine resulted in the recurrence of severe symptoms in 15 patients (79%). 4 Pharmacokinetic studies showed the mean elimination half-life of cimetidine to be 100 +/- 25 min, the total body cimetidine clearance 652 +/- 223 ml/min, the mean volume of distribution at steady state 65 +/- 181 and the overall bioavailability 78%. 5 Long term cimetidine treatment does not result in drug accumulation or changes in its pharmacokinetic profile. 6 Inter-individual differences in clinical and endoscopic response to cimetidine cannot be explained by pharmacokinetic differences.

The radiological assessment of gastric acid output in chronic renal failure

The presence of hypertrophied gastric and duodenal mucosa as seen in the barium meal examination has been widely accepted as indicating an increase in gastric acid content. The present study of 31 uraemic patients undergoing maintenance haemodialysis suggests that in the uraemic patient this is not the case. Nineteen showed hypertrophy of the gastric mucosa radiologically but only eight had an abnormal pattern of gastric secretion. Of the 12 patients with a normal gastric and duodenal mucosal pattern, four showed an increase in the acid output of the stomach. It is concluded that the radiologist should beware of equating hypertrophy of the gastric and duodenal mucosa with a high gastric acid output in the chronically uraemic patient.

Penicillamine-induced polymyositis-dermatomyositis

Two patients with classical rheumatoid arthritis developed myopathy during treatment with penicillamine. In both patients, electromyography and muscle biopsies were indicative of polymyositis. In one patient, muscle enzymes were not examined at the appropriate time; in the other patient muscle enzymes were raised. This latter patient also had a rash and, in the dermal epidermal junction of pathological skin, granular deposits of immunoglobulin and complement were found. The myopathy subsided in both patients after withdrawal of penicillamine.

[Riskfactors and coronary morphology in 218 patients with myocardial infarction under 40 years of age (author's transl)]

With 218 postinfarction patients under 40 years of age who all underwent coronary angiography, the question in priority is: Can myocardial infarction in young age be characterized by special constellation of risk factors and by specific coronary morphology? Compared with results from literature the risk factors hypertension and diabetes seem to be of less importance than in older patients, smoking on the other hand seems to be more significant: 90.5% of postinfarction patients under 40 years of age were smoking regularly. Coronary angiography proved a pre-domination of 1-vessel disease: 72% showed 1-vessel, 17.9% 2-vessel and 10.1% 3-vessel disease. These findings and those from literature show that the majority of patients with myocardial infarction in young age have the following characteristics: In connection with the risk factor smoking the sclerotic coronary vessel process is developing rapidly, very often at a single spot. Since no longterm gradual occlusion process occurs, no prolonged period of angina pectoris precedes the infarction. There is no time for the development of an adequate collateral circulation; it follows that the infarction is a large one. After the acute infarction there is no angina pectoris.