Morphological aspects of LFA-1/ICAM-1 and VLA4/VCAM-1 adhesion pathways in human lymph nodes

Monoclonal antibodies specific for the adhesion molecules participating in lymphocyte homing, lymphocyte function associated antigen-1 (LFA-1) and very late antigen 4 (VLA4), and their respective ligands, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), were used to characterize their expression pattern in human lymph nodes by immunohistochemical and immunoelectron microscopic techniques. The location of LFA-1-positive lymphocytes and selective expression of ICAM-1 on the luminal plasma membrane of high endothelial venule endothelium suggested that the LFA-1/ICAM-1 adhesion pathway participates only in the initial step of the lymphocyte migration process. Lymphocytes passing through endothelium appear not to be influenced by this pathway. VCAM-1 was detected occasionally on the endothelium of high endothelial venules in the hyperplastic lymph nodes in the mesentery, but not in peripheral lymph nodes. VLA4-positive lymphocytes tended to be more frequently observed within high endothelial venules in mesenteric lymph nodes than in peripheral ones. Strong expression of both ligands, ICAM-1 and VCAM-1, was noted on the plasma membrane of follicular dendritic cells, and was especially prominent on their labyrinthine folding, and on the interdigitating cells in the paracortex. Furthermore, both LFA-1- and VLA4-positive lymphocytes localized around these cells. This suggests that LFA-1/ICAM-1 and VLA4/VCAM-1 adhesion pathways play an important role in the lymphocyte recognition of antigen-presenting cells.

Physiological increase in plasma insulin concentration suppresses proinsulin secretion in normal controls but not in subjects with glucose intolerance

Since insulin negatively controls its own secretion, we examined if insulin also inhibits the secretion of its precursor, proinsulin, in subjects with varying degrees of glucose tolerance. Under comparable hyperinsulinemia (50-70 microU/ml) achieved by the euglycemic insulin clamp technique, plasma C-peptide concentrations were equally suppressed to approximately 40-50% in nonobese subjects with normal glucose tolerance (NGT) (n = 13, 35.5 +/- 3.7%, M +/- SEM), borderline glucose intolerance (BGI) (n = 12, 46.7 +/- 5.6%), and non-insulin-dependent diabetes mellitus (NIDDM) (n = 12, 48.9 +/- 5.4%). In contrast, plasma proinsulin concentrations were slightly but significantly suppressed in NGT (4.1 +/- 0.2 to 3.7 +/- 0.2 pmol/L, P < 0.05), but not in patients with BGI (4.6 +/- 0.3 to 4.8 +/- 0.5 pmol/L, NS) and NIDDM (5.5 +/- 0.5 to 4.9 +/- 0.4 pmol/L, NS). The basal concentrations of proinsulin increased as glucose tolerance declined (P < 0.05 between NGT and NIDDM). These results suggest that the basal secretion of proinsulin by beta-cells seems relatively insensitive to insulin compared with C-peptide, and that the insulin-proinsulin feedback loop is disturbed in glucose-intolerant subjects. Therefore, a defective feedback inhibition of proinsulin secretion by insulin may be partly involved in the disproportionate increase of plasma proinsulin concentrations in patients with NIDDM.

Characteristics of gangliosides including O-acetylated species in growth cone membranes at several developmental stages in rat forebrain

Growth cones, the motile tips of extending neuronal processes, are involved in accurate synaptogenesis. To study the developmental changes in ganglioside composition including O-acetylated gangliosides in growth cones, we analyzed the gangliosides in growth cone membranes (GCM) prepared from rat forebrains at different developmental stages. At several stages, GCM contained significantly larger amounts of gangliosides than the other membrane subfractions. The ganglioside content of GCM increased in amount with development. Moreover, in GCM, the relative amount of GD3 gradually decreased, and that of GD1a dramatically increased. There were significant differences in the composition of ganglioside species between GCM and the perinuclear plasma membrane subfraction (NM); most importantly, GCM had a higher ratio of GD1a to GM3 plus GD3 than NM. There were three different O-acetylated gangliosides in GCM: O-acetyl-GD3, O-acetyl-GT1b, and O-acetyl-GQ1b. The molar ratio of O-acetyl-GD3 decreased in GCM at later stages (5% of the total gangliosides at embryonic day 17, to 1% at postnatal day 5). However, those of the other two O-acetylated gangliosides were almost constant (1-2% of the total). Our results show that there are significant differences in ganglioside content and composition between the membrane subfraction of growth cones and the perinuclear portion. This suggests that several species of gangliosides, including O-acetyl-GD3, play a role in growth cone function.

Rat spinal cord neurons contain nitric oxide synthase

We describe the distribution and characteristics of nitric oxide synthase-containing neurons in rat spinal cord using a polyclonal affinity-purified antibody against rat cerebellar nitric oxide synthase. Numerous neurons were stained throughout the entire rostrocaudal extent of the spinal cord. Cell bodies, dendrites and axons stained in a uniform manner. Nitric oxide synthase immunoreactivity was intense in neurons of laminae I-IV and X throughout the entire spinal cord. Neurons in the intermediolateral cell column of the thoracic and lumbar spinal cord were also intensely stained for nitric oxide synthase. The sacral cord demonstrated substantial nitric oxide synthase immunostaining within lamina VII. For the entire cord, scattered neurons in laminae V, VI, VII, and VIII were weakly positive. In addition, punctate nitric oxide synthase staining throughout laminae I, III and surrounding some large motor neurons in the ventral horn suggested the presence of nitric oxide synthase at synapses. Axons and dendritic terminals located in the gray and white matter were also stained. The majority of nitric oxide synthase positive neurons in the intermediolateral cell column were double-labelled by subcutaneously injected FluoroGold confirming that these cells were preganglionic autonomic neurons. Most NADPH-diaphorase-stained neurons were also nitric oxide synthase-positive. The distribution of nitric oxide synthase-containing neurons in spinal cord suggests that nitric oxide plays a role in spinal cord neurotransmission including: preganglionic sympathetic and parasympathetic, somatosensory, visceral sensory and possibly motor pathways. In particular, the autonomic nervous system appears enriched with nitric oxide synthase immunoreactivity. The precise role of each neuron type remains to be demonstrated in physiologic and pathophysiologic paradigms.

[Vestibular function in bilateral idiopathic progressive sensorineural hearing loss]

To investigate vestibular function in patients with bilateral progressive sensorineural hearing loss (BPSHL), we examined 5 cases using electronystagmography. Cases 1, 2 and 3 were adult type, cases 4 and 5 were juvenile type. All patients had dizzy spells in the early stage of the disease, and showed spontaneous nystagmus. Bilateral reduction of caloric response and very low VOR (vestibulo-ocular reflex) gain on rotation testing were observed in cases 1, 2 and 3. Case 4 showed right canal paresis on the caloric test and left directional preponderance on the rotation test. Case 5 showed good responses to both tests. Optokinetic afternystagmus (OKAN) in cases 2, 3 and 5 was not brisk, and cases 1 and 4 showed directional preponderance of OKAN. Although OKAN is useful for detecting directional preponderance, it does not always reflect peripheral vestibular function. We suggest the existence of two types of BPSHL which correlate with vestibular function. One type is associated with high grade vestibular dysfunction while, in the other, vestibular function is fair.

A case of the 'dapsone syndrome'

The 'dapsone syndrome' developed in a 44-year-old woman who was treated for pyoderma gangrenosum with 100 mg/day dapsone for about 5 weeks. Symptoms included fever, malaise, jaundice with hepatic dysfunction, lymphadenopathy, mononucleosis and dermatitis. These symptoms disappeared with 30 mg/day of oral prednisolone. A lymphocyte stimulation test with dapsone was positive, as was the delayed-type intradermal skin test with 0.5 and 0.05% dapsone in saline. Immunohistochemical studies of the rash and skin test reaction revealed that the dominant infiltrating T cells in the upper dermis were of the Leu 2a+ cytotoxic/suppressor-type rather than the Leu 3a+ helper/delayed hypersensitivity-type.

Macrophage colony-stimulating factor induces the growth and differentiation of normal pregnancy human cytotrophoblast cells and hydatidiform moles but does not induce the growth and differentiation of choriocarcinoma cells

In the present study, we examined whether or not macrophage colony-stimulating factor (M-CSF; CSF-1) is involved in the growth and differentiation of human chorionic, hydatidiform mole and choriocarcinoma cells. M-CSF promotes the growth of early gestation chorionic cells, hydatidiform mole cells, and a human term placenta cell line (tPA30-1). However, the growth of choriocarcinoma cells, BeWo, Jar, Jeg-3, and NUC-1, was not influenced at all by M-CSF. M-CSF promoted the secretion of human chorionic gonadotropin (hCG) and human placental lactogen (hPL), which are secreted from differentiated trophoblast, from early gestation chorionic cells and from hydatidiform mole cells. However, the secretion of hCG and hPL from choriocarcinoma cells was not affected by M-CSF. When M-CSF localization was examined by immunohistochemical staining, M-CSF was detected in chorionic and hydatidiform mole cells, but was absent in choriocarcinoma cells. These results suggest that the growth and differentiation of normal chorionic and hydatidiform mole cells are M-CSF-dependent, while the growth and differentiation of choriocarcinoma cells are not.

Complementary DNA sequence encoding the major neural cell adhesion molecule isoform in a human small cell lung cancer cell line

The neural cell adhesion molecule (N-CAM), a member of the immunoglobulin gene super-family mediating homophilic cell-cell adhesion in a neuroendocrine system, is preferentially expressed in human small cell lung cancer (SCLC). Immunoprecipitation of a panel of SCLC cell lines by monoclonal antibodies (mAbs) specific for N-CAM detects mainly the 145-kDa isoform. This result was correlated with Northern blotting where a single 6.2-kb mRNA was detected in nine SCLC cell lines. To determine cDNA sequence encoding the N-CAM isoform, we selected several cDNA clones encoding N-CAM isolated from OS2-R, a SCLC cell line established in our laboratory. Based on the analysis of the full-length cDNA obtained from two clones, the sequence of this 145-kDa isoform was shown to be essentially identical to that of the 140-kDa N-CAM isoform of neuroblastoma except for a single base pair changed at position 1620 without changing amino acid encoded.

What effect can rhythmic finger tapping have on the phonological similarity effect?

The effects of rhythmic finger tapping on the phonological similarity effect were investigated in two experiments. In both, subjects were tested for serial recall of visually presented letter sequences that were either phonologically similar or dissimilar. The letter sequences had to be remembered under three tapping conditions: right-hand tapping, left-hand tapping, and a no-tapping control. Experiment 1 showed clear phonological similarity effect in both the control and the left-hand tapping conditions, but not in the right-hand tapping condition, when recall responses were written with the right hand. When the number of tapping practice trials was fixed at two and recall was vocal in Experiment 2, the phonological similarity effect was eliminated in both the right-hand and the left-hand tapping conditions. These results suggest that some form of speech motor programs played an important role in serial recall.

Microwave ablation of the atrioventricular junction in vivo and ventricular myocardium in vitro and in vivo. Effects of varying power and duration on lesion volume

Catheter ablation in ventricular tachycardia has achieved only limited success using direct current (DC) and radiofrequency (RF) energy, due to either high complication rates or a limited lesion size. Microwave energy represents a possible alternative source of energy for percutaneous ablation of the ventricular myocardium. However, an optimal method for titration of the dose of microwave energy to achieve the desired lesion volume has not yet been established. The safety and efficacy of microwave ablation of the atrioventricular (AV) junction were studied in 11 dogs in vivo. The relationship between lesion size following microwave ablation and the power output of or exposure duration to microwave energy was also examined at disparate sites in each superfused left ventricular epicardium in vitro. To observe the pathologic changes in the myocardium after microwave ablation, microwave ablation of the endocardium of the left ventricle was carried out in 9 dogs in vivo. Complete AV block was achieved in 10 of the above 11 dogs with a mean of 5 applications of microwave energy. The lesion volume in vitro demonstrated a parallel increase with power (r = 0.76) and duration (r = 0.81). The mean lesion volume at 30 sec was: at 10W, 0.8 +/- 1.6; 20 W, 34.7 +/- 10.3; 30 W, 34.7 +/- 22.4: 40 W, 64.7 +/- 64.4; 50 W, 87.2 +/- 42.3; 60 W, 85.8 +/- 38.1; 70 W, 124.7 +/- 36.5; 80 W, 134.2 +/- 49.0 mm3. The mean lesion volume at 80 W was: at 15 sec, 32.6 +/- 37.8; 30 sec, 101.2 +/- 46.4; 60 sec, 180.6 +/- 80.1; 120 sec, 291.8 +/- 122.7; and 180 sec, 459.3 +/- 204.6 mm3. The ablated lesions showed discrete, homogeneous coagulation necrosis with sharp margins from the adjacent normal myocardium. Microwave energy may thus be more effective than RF energy, and have a lower risk of complications and arrhythmogenesis than DC energy when used for ablation in ventricular tachycardia.

Molecular cloning and sequencing of porcine somatostatin receptor 2

The porcine somatostatin receptor gene was isolated from a porcine genomic library. Based on the deduced amino acid sequence, this gene encodes a 369 amino acid protein with seven hydrophobic segments, a characteristic of G-protein coupled receptors, and shows only 13 amino acid difference (identity 96.5%, similarity 99.2%) in amino acid sequence from human somatostatin receptor 2. The data indicate that the amino acid sequence is highly conserved in pig, human, rat and mouse somatostatin receptor 2.

Common tetrasaccharide epitope NeuAc alpha 2-->3Gal beta 1-->3(Neu-Ac alpha 2-->6)GalNAc, presented by different carrier glycosylceramides or O-linked peptides, is recognized by different antibodies and ligands having distinct specificities

A novel globo-series disialoganglioside, disialosyl galactosyl globoside (Structure 1 below), defined by new monoclonal antibody (mAb) RM2, was isolated and characterized as having terminal structure identical to that of ganglio-series ganglioside GD1 alpha (Structure 2) and a common mucin-type epitope (Structure 3) widely distributed in glycoproteins such as glycophorin A. While these three structures share a common nonreducing tetrasaccharide terminus, mAb RM2 showed strong specific reactivity only with Structure 1, not with Structures 2 or 3. Another mAb, QSH2, reacted strongly with Structure 3 but did not cross-react with Structures 1 or 2. Conformational molecular models based on minimum energy hard sphere exoanomeric calculations suggest that Structure 1 presents a unique surface topology distinct from that of Structures 2 or 3. Our findings suggest the novel concept that reactivity of a common carbohydrate epitope with different antibodies or ligands is highly dependent on the type of carrier glycosylceramide or carrier O-linked peptide. [formula: see text]

Spinal epidural hematoma with spontaneous recovery demonstrated by magnetic resonance imaging

The authors report the sixth case of spinal epidural hematoma with spontaneous recovery, which was demonstrated on serial magnetic resonance images. These images showed the course and plausible mechanism of disappearance of the hematoma.

Ultrastructural localization of myoglobin mRNA in human skeletal muscle

The intracellular localization of myoglobin mRNA in the skeletal muscles of normal subjects was examined by in situ hybridization using a biotin-labeled cDNA probe. By phase-contrast microscopy, myoglobin mRNA signals were demonstrated to be located preferentially on the A-band. Two different methods of tissue preparation, i.e., pre-embedding method and post-embedding method, were used for the electron microscopic study. With the pre-embedding method, only a few gold particles were found to be associated with cytoskeletal filaments in the intermyofibrillar space. With the post-embedding method, superior preservation of sections and higher signal intensities were obtained. Although most of the gold particles were localized on the A-band, some were seen in other regions; i.e., in the intermyofibrillar space, perinuclear space, or the I-band, where myoglobin is localized. These findings suggest that myoglobin is primarily synthesized on the A-band, where ribosomes predominantly exist, although myoglobin is also localized on the I-band. The predominant localization of myoglobin mRNA on the A-band may aid in the mRNA transcription and may be related to the regulation of myoglobin synthesis in skeletal muscle cells.

[Microvascular mechanisms of change in tumor blood flow elicited by vasopressors]

To elucidate the microvascular mechanisms of change in tumor blood flow due to vasopressors (angiotensin II, epinephrine, methoxamine), we analyzed the site of vascular resistance (VR) increased by each vasopressor. Arteriolar vessels within a transparent rat chamber were classified centripetally (a2-a5) according to Strahler's nomenclature. Vessels that feed into the tumor microcirculation were a2 modified by the tumor (starting vessels). Under angiotensin II (A II)-induced hypertension, the pressure of all arteriolar vessels increased roughly in proportion to the increase in mean arterial blood pressure. The greatest pressure drop and hence the most resistance due to A II occurred across the a2. During epinephrine-induced hypertension, there were major pressure drops between a4 and a3, and between a3 and a2. The amount of contraction of arteriolar vessels due to methoxamine was much smaller than that due to epinephrine, and the pressure increase in a4 and a3 was also small. From the facts described above, we may conclude as follows: A II creates greater vascular resistance of a2 vessels to blood flow and also greater perfusion pressure of a5-a3 vessels, resulting in increased blood inflow into a starting vessel which then becomes a passive vessel. Epinephrine causes an increase in the resistance of a3, a4 and probably upstream from a4 arterioles to blood flow. Thus, tissue blood flow in subcutis and tumor almost always decreases together. The fact that tissue blood flow in normal subcutis and tumor did not change significantly under methoxamine-induced hypertension is probably due to the results that methoxamine had little effects on the vascular resistance of smaller arterioles to blood flow.

Protein S Tokushima: abnormal molecule with a substitution of Glu for Lys-155 in the second epidermal growth factor-like domain of protein S

A 29-year-old female patient with heterozygous congenital protein S deficiency suffering from thrombotic disease had normal levels of both total and free protein S antigen (70% and 65%, respectively), but low cofactor activity (31%) for activated protein C, indicating that she had a variant of protein S, protein S Tokushima. Western blotting using the polyclonal anti-protein S antibody showed that approximately half of the patient's protein S appeared to be the variant with a higher molecular weight than normal protein S. The partially purified variant protein S bound neither to the monoclonal antibody recognizing calcium-dependent conformation of protein S nor to the antibody recognizing the thrombin-sensitive domain of protein S. Among the exons from II to XV of the patient's protein S gene encoding from the NH2-terminal end to the COOH-terminal end of protein S, only one missense mutation (A to G) was found in exon VI of the protein S alpha-gene, which results in amino acid substitution of Glu(GAG) for Lys-155(AAG) in the second epidermal growth factor-like domain of protein S. The recombinant protein S Tokushima expressed in BHK cells had a slightly higher molecular weight than the recombinant normal one, did not bind to the antibody specific for the thrombin-sensitive domain, and did not show the cofactor activity. These findings suggest that the protein S Tokushima molecule is structurally and functionally a variant of protein S, and that this variant protein S is the cause of severe thrombosis in this patient.

Unresponsiveness of antidonor cytotoxic T cells in a long-term stable renal transplant recipient

The antidonor immune response was examined in a one haplotype-mismatched renal transplant recipient with an allograft that had been well-functioning for more than 10 years. Although the relative response of the mixed lymphocyte reaction (MLR) was (45.8)% and the MLR responder cells stimulated by donor cells produced measurable amounts of interleukin-2 (IL-2) (11.6 U/ml), the cytotoxic T lymphocytes (CTL) could not be generated against donor cells, even with exogenous IL-2. These results indicate that antidonor CTL precursors were either deleted or inactivated in this recipient.

Immunohistochemical study of graft-versus-host reaction (GVHR)-type drug eruptions

Skin biopsies of graft-versus-host reaction (GVHR)-type drug eruptions in the acute phase were compared immunohistochemically with those in the chronic phase and also with non-GVHR type drug eruptions in the acute phase. Predominance of CD8+ T cells in the epidermal infiltrates, reduction in the number of epidermal OKT6+ dendritic cells (Langerhans cells), and increased expression of HLA-DR and ICAM-1 on keratinocytes were observed in the acute phase of GVHR-type, but not in either the chronic phase of GVHR-type or the acute non-GVHR type. These findings were similar to those of previous reports on skin lesions of acute GVH disease (GVHD) seen after bone marrow transplantation. Therefore, immunohistochemistry is not useful for differential diagnosis between acute GVHR-type drug eruptions and acute cutaneous GVHD. These findings also indicate that similar immunomechanisms may be involved in the pathogenesis of both GVHR-type drug eruptions and cutaneous GVHD.

[Rescue effect of 15-deoxyspergualin for acute rejection on heart transplantation--using a rat model]

15-Deoxyspergualin (DSG) attracts a lot of attention as an immunosuppressive drug which has less side effects these days. In the present study, we researched the rescue effect of DSG for acute rejection on heart transplantation (HTX) by using rat models. We performed 40 heterotopic heart transplantation models. We injected them DSG (group A: 5 mg/kg/day, group B: 10 mg/kg/day) intravenously through 3 days, starting from the 3rd day the 4th day, and the 5th day after HTX. Our previous study showed the pathology on the 3rd day after HTX corresponded to mild rejection, the 4th day to moderate rejection, and the 5th day to severe rejection. One day after the injection was completed, the recipients were sacrificed. The rescue effect was histopathologically assessed by H-E stain, and the action mechanism of DSG was considered by immunohistochemical stain using monoclonal antibodies, which were against CD4 positive cells, CD8 positive cells, and macrophages. In result, the rescue effect of DSG was significant in all groups, in comparison with controls, which had no immunosuppression. And the rescue effect of group B was superior to group A. We also found using a immunohistochemical technique, that DSG inhibited the accumulation of CD4 and CD8 positive cells. We concluded the rescue effect of DSG for acute rejection on HTX was significant, especially in 10 mg/kg/day even in the severe rejection. And the suppression of helper and cytotoxic T cells accumulation might be one of the action mechanisms of DSG.

Physiological indices of visual fatigue due to VDT operation: pupillary reflexes and accommodative responses

In spite of the clarification of some significant physiological factors of visual fatigue caused by VDT work, pupillary reflexes have not been studied as to how they are affected after prolonged visual work. This study examined visual function changes objectively in terms of pupillary reflexes and lens accommodative responses after a 4-hr VDT operation task. The relationship between the two functions was also examined. Two measurements in this paper revealed the physiological function changes due to VDT operation. The subjects involved were five students with an average age of 22.6 years. First, near-reflex measurement ascertained decreases in amplitude and the velocity of accommodation function after the visual task. Second, light-reflex measurement revealed a delay of the reflex, an increase in the amplitude of the reflex, and a decrease in pupil size after the visual task. A weak correlation between the decrease in pupil size and accommodation function was found. The occurrence of visual fatigue due to 4-hr VDT operation was also confirmed by CFF measurements and reported subjective visual symptoms in this experiment.

Preferential induction of IL-4 is determined by the type and duration of antigenic stimulation

The transition of lymphokine production from IL-2 to IL-4 was investigated with antigen-primed lymph node cells (LNC) by observing cytokine release following sequential cycles of antigen exposure in vitro. LNC from mice infected with Nippostrongylus brasiliensis (Nb), Trichinella spiralis, or primed with giant ragweed pollen demonstrated a pattern of dominant IL-2 production at 24 hr; however, there was a switch to predominantly IL-4 production within 72 hr following the first cycle of in vitro antigenic stimulation. In addition, repeated antigenic stimulation with these antigens shifted the pattern to IL-4 production. In contrast, only IL-2 production was observed after a single cycle of in vitro antigenic challenge with haptens (e.g., NP-O-succinimide or trimethylammonium hapten) or the naive allogenic spleen cells. Thereafter, the lymphokine production pattern gradually changed from IL-2 alone to mixtures of IL-2 and IL-4, and finally to predominant IL-4 secretion. In contrast, following priming with purified protein derivatives (PPD), it was difficult to detect IL-4 release even after nine successive weekly stimulations. However, activation of PPD-primed cells with anti-CD3 antibody resulted in IL-4 secretion. Furthermore, Nb-primed T cells, which produced IL-4 alone after repeated antigenic stimulation, produced IL-2 when stimulated in the presence of cycloheximide. These results suggest that (1) immune populations regulate cytokine production, (2) the IL-2/IL-4 profile is dependent on the type and duration of antigenic stimulation, and (3) production or accumulation of cycloheximide-sensitive proteins is critical for the switch from IL-2 to IL-4 secretion.

Enhanced secretion and impaired natriuretic action of atrial natriuretic peptide in response to hypertonic saline infusion in patients with essential hypertension

To clarify the natriuretic action of endogenous atrial natriuretic peptide (ANP) in patients with essential hypertension (EHT), we examined the relationship between ANP release and urinary sodium excretion in response to hypertonic saline infusion. Plasma ANP levels increased from 13.3 +/- 2.0 pg/ml to 37.0 +/- 3.0 pg/ml in patients with EHT and from 9.2 +/- 1.5 pg/ml to 21.1 +/- 4.0 pg/ml in normal subjects after the infusion. The area under the curve (AUC) of plasma ANP response was significantly higher in patients with EHT than in normal subjects (P < 0.05). There was a significant positive correlation between AUC and urinary sodium excretion in both groups (P < 0.01). However, the ratio of urinary sodium excretion to AUC was significantly lower in patients with EHT than in normal subjects (P < 0.01). These results suggest that impaired natriuretic response to endogenous ANP is one of the factors responsible for the development of EHT and that enhanced secretion of ANP in response to hypertonic saline infusion is a compensatory mechanism to the impaired natriuretic action of ANP in patients with EHT.

The influence of intravenous immunoglobulin treatment on maternal immunity in women with unexplained recurrent miscarriage

PROBLEM

Recently the protective value of high-dose intravenous immunoglobulin (IVIG) in the treatment of unexplained recurrent miscarriage has been reported to be similar to that of conventional immunotherapy with paternal leukocytes. We examined the effect of IVIG treatment on the cellular and humoral level of maternal immunity to demonstrate the possible mechanism by which IVIG might act to prevent recurrence of pregnancy loss.

METHOD

Eight patients were treated with a 20- to 25-g dose of IVIG every 2 to 3 wk during their first-trimester pregnancies. The development of anti-idiotypic autoantibodies against maternal T-cell receptors, maternal anti-paternal lymphocyte antibodies detected by flow cytometric crossmatch, and changes of maternal lymphocyte subpopulations were monitored before pregnancy and then weekly during IVIG treatment.

RESULTS

Five of eight patients gave birth successfully after IVIG treatment given during the first trimester of pregnancy (success rate: 62.5%). Although we could not demonstrate a general immunological effect of IVIG on maternal immunity in vivo, a few significant changes of immunological parameters were found in some patients.

CONCLUSION

Our results suggest that the effect of IVIG on maternal immunity is not a passive increase of blocking antibody including anti-HLA antibody or modification of maternal T-cell subsets but, more likely, a passive increase of anti-idiotypic antibody against anti-HLA antibody or soluble HLA antigens. However, whether the immunomodulating effect of IVIG is related to its possible mechanism to prevent abortion remains unestablished.