A novel protocol for de-isolating moderately and severely immunocompromised COVID-19 patients

Immunocompromised coronavirus disease 2019 patients are at a higher risk of prolonged viral shedding than immunocompetent patients. However, as of August 2023, there is no clear international standard for de-isolating vulnerable patients. A comprehensive assessment is advisable based on various information, such as the increase in immune escape of specific mutant strains as well as the patient's innate immunity and vaccination status; therefore, consultation with an infectious disease specialist is recommended. The patient population defined as moderately or severely immunocompromised by the Centers for Disease Control and Prevention and the European Centre for Disease Prevention and Control is significantly broad. A boundary between the two remains to be delineated, and the existing protocols allow the release of patients based on their symptoms alone. This may lead to an unnecessary extension or premature termination of isolation. In this study, we searched for studies, particularly those that used real-world data, discussed the results with experts in our hospital, and proposed new isolation criteria based on both testing and clinical symptoms. We classified patients into three groups namely severely, moderately, and mildly immunocompromised, defined by their background and the administration of immunosuppressive drugs. A separate flowchart for ending isolation is indicated for each group. This standard may be a useful support material, especially for non-specialists. Nevertheless, our criteria must be revised and added continuously; accumulating real-world data to support revision of and addition to the list is becoming increasingly important.

The safety of plasma apheresis from donors recovering from COVID-19 infection in Japan

PURPOSE

Since 2020, the novel coronavirus infection (COVID-19) has spread globally. A few studies have investigated the safety of COVID-19 convalescent plasma (CCP) apheresis from COVID-19. This study was the first retrospective observational study of CCP in Japan.

METHODS

We recruit donors from April 2020 to November 2021 and plasmapheresis in our center (NCGM: national center for global health and medicine). We set the primary endpoint as the Donors Adverse Event (DAE) occurrence at the time of the CCP collection. Variable selection was used to explore the determinants of DAE.

RESULTS

Mean and SD age was 50.5 (10.6) years old. Seventy-three (42.2 %) were female, and 87 (33.3 %) were multiple-times donors. Twelve (6.97 % by donors and 4.6 % in total collections) adverse events occurred. The DAEs were VVR (Vaso Vagal Reaction), paresthesia, hypotension, agitation, dizziness, malaise, and hearing impairment/paresthesia. Half of them were VVR during apheresis. DAE occurred only in first-time donors and more in severe illnesses such as using ventilation and ECMO. From the donor characteristics and variable selection, the risk factors are as follows: younger age, female, the severity of disease at the time of the disease, and lower SBP before initiation. Our DAE incidence did not differ from previous studies. DAEs were more likely to occur in CCP apheresis than in healthy donors.

CONCLUSION

We confirm the safety of CCP apheresis in this study, although DAEs were more than healthy donors. More caution should be exercised in the plasma collection for future outbreaks of emerging infectious diseases.

[Fibrinolytic factors: novel molecular targets for cytokine storm-associated diseases]

The mortality rate due to coronavirus disease 2019 (COVID-19) reached 5.3 million. However, identifying the novel treatment targets that ultimately reduce or prevent disease aggravation will be possible by understanding the mechanism and pathophysiology underlying the COVID-19 aggravation. Authors of previous studies have identified the "cytokine storm" that constitutes the secretion of inflammatory cytokines driven by the coagulation/fibrinolytic system as an inflammatory cytodynamic control mechanism that contributes to the aggravated COVID-19 pathology and the pathophysiology of related diseases. Vasculature-lining endothelial cells are bioreactors that produce or contribute to the modulation status of cytokines and coagulation and fibrinolytic system factors. The key steps in the pathophysiology of organ damage include the destabilization of the angiocrine system triggered by vascular endothelial damage during severe COVID-19. Overproduced or imbalanced angiocrine factors and inflammatory cytokines contribute to major COVID-19 complications. Within its scope, this study outlines the significance of the fibrinolytic system in the pathophysiology of inflammatory diseases, focusing on the research results. The possibility of molecular that target these angiocrine and fibrinolytic factors for inflammatory diseases as novel treatment approaches for inflammatory diseases, such as COVID-19, was discussed.

Rituximab-induced Acute Thrombocytopenia in a Patient with Follicular Lymphoma: A Case Report and Review of the Literature

Rituximab is a highly effective agent that is used in the treatment of B-cell lymphoma. Rituximab-induced acute thrombocytopenia is a rare side effect that has previously been reported in a small number of patients with malignant lymphoma; its mechanism is still unknown. We herein report the case of a 74-year old man who was diagnosed with follicular lymphoma and who developed severe acute thrombocytopenia the day after the administration of rituximab. Coagulation abnormality, which mimicked disseminated intravascular coagulation, also appeared. When physicians use rituximab to treat high-risk patients, the platelet count should be closely monitored to avoid possible adverse events.

Cancer therapy targeting the fibrinolytic system

The tumor microenvironment is recognized as a key factor in the multiple stages of cancer progression, mediating local resistance, immune-escape and metastasis. Cancer growth and progression require remodeling of the tumor stromal microenvironment, such as the development of tumor-associated blood vessels, recruitment of bone marrow-derived cells and cytokine processing. Extracellular matrix breakdown achieved by proteases like the fibrinolytic factor plasmin and matrix metalloproteases is necessary for cell migration crucial for cancer invasion and metastasis. Key components of the fibrinolytic system are expressed in cells of the tumor microenvironment. Plasmin can control growth factor bioavailability, or the regulation of other proteases leading to angiogenesis, and inflammation. In this review, we will focus on the role of the fibrinolytic system in the tumor microenvironment summarizing our current understanding of the role of the fibrinolytic factors for the modulation of the local chemokine/cytokine milieu, resulting in myeloid cell recruitment, which can promote neoangiogenesis.

Role of mesenchymal stem cell-derived fibrinolytic factor in tissue regeneration and cancer progression

Tissue regeneration during wound healing or cancer growth and progression depends on the establishment of a cellular microenvironment. Mesenchymal stem cells (MSC) are part of this cellular microenvironment, where they functionally modulate cell homing, angiogenesis, and immune modulation. MSC recruitment involves detachment of these cells from their niche, and finally MSC migration into their preferred niches; the wounded area, the tumor bed, and the BM, just to name a few. During this recruitment phase, focal proteolysis disrupts the extracellular matrix (ECM) architecture, breaks cell-matrix interactions with receptors, and integrins, and causes the release of bioactive fragments from ECM molecules. MSC produce a broad array of proteases, promoting remodeling of the surrounding ECM through proteolytic mechanisms. The fibrinolytic system, with its main player plasmin, plays a crucial role in cell migration, growth factor bioavailability, and the regulation of other protease systems during inflammation, tissue regeneration, and cancer. Key components of the fibrinolytic cascade, including the urokinase plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1), are expressed in MSC. This review will introduce general functional properties of the fibrinolytic system, which go beyond its known function of fibrin clot dissolution (fibrinolysis). We will focus on the role of the fibrinolytic system for MSC biology, summarizing our current understanding of the role of the fibrinolytic system for MSC recruitment and the functional consequences for tissue regeneration and cancer. Aspects of MSC origin, maintenance, and the mechanisms by which these cells contribute to altered protease activity in the microenvironment under normal and pathological conditions will also be discussed.

Inhibition of plasmin protects against colitis in mice by suppressing matrix metalloproteinase 9-mediated cytokine release from myeloid cells

BACKGROUND & AIMS

Activated proteases such as plasmin and matrix metalloproteinases (MMPs) are activated in intestinal tissues of patients with active inflammatory bowel diseases. We investigated the effect of plasmin on the progression of acute colitis.

METHODS

Colitis was induced in Mmp9(-/-), Plg(-/-), and C57BL/6 (control) mice by the administration of dextran sulfate sodium, trinitrobenzene sulfonic acid, or CD40 antibody. Plasmin was inhibited in control mice by intraperitoneal injection of YO-2, which blocks its active site. Mucosal and blood samples were collected and analyzed by reverse-transcription polymerase chain reaction and immunohistochemical analyses, as well as for mucosal inflammation and levels of cytokines and chemokines.

RESULTS

Circulating levels of plasmin were increased in mice with colitis, compared with controls. Colitis did not develop in control mice injected with YO-2 or in Plg(-/-) mice. Colons from these mice had reduced infiltration of Gr1+ neutrophils and F4/80+ macrophages, and reduced levels of inflammatory cytokines and chemokines. Colonic inflammation and colitis induction required activation of endogenous MMP9. After colitis induction, mice given YO-2, Plg(-/-) mice, and Mmp9(-/-) mice had reduced serum levels of tumor necrosis factor and C-X-C motif chemokine ligand 5, compared with control mice.

CONCLUSIONS

In mice, plasmin induces a feedback mechanism in which activation of the fibrinolytic system promotes the development of colitis via activation of MMP9 or proteolytic enzymes. The proteolytic environment stimulates the influx of myeloid cells into the colonic epithelium and the production of tumor necrosis factor and C-X-C motif chemokine ligand 5. In turn, myeloid CD11b+ cells release the urokinase plasminogen activator, which accelerates plasmin production. Disruption of the plasmin-induced chronic inflammatory circuit therefore might be a strategy for colitis treatment.

Role of glycinergic inhibition in shaping activity of saccadic burst neurons

The immediate premotor signals for saccades are created at the level of medium-lead burst neurons (MLBNs). During fixations, MLBNs receive tonic inhibition from omnipause neurons (OPNs), which use glycine as a neurotransmitter. To elucidate the role of this inhibition, we studied discharge patterns of horizontal MLBNs following iontophoretic application of strychnine, a glycine-receptor antagonist, in alert cats. Three-barrel micropipettes were used for extracellular recording and iontophoresis. After application of strychnine, MLBNs exhibited spontaneous discharge and visual responses during intersaccadic intervals. Spikes were evoked by single-pulse stimulation of the contralateral superior colliculus (SC). These results show that MLBNs receive substantial excitatory input during intersaccadic intervals and that inhibitory action of OPNs is indeed necessary to prevent MLBNs from firing. Strychnine also affected saccade-related activity of MLBNs. The burst of activity, as in normal conditions, declined rapidly before the end of saccades but was followed by low rate spike activity, which continued beyond the end of saccades. This suggests that in normal conditions, the termination of saccades is determined by resumed inhibitory action of OPNs and not by termination of excitatory input to MLBNs. In addition, the firing rate and the number of spikes during saccades increased after strychnine application, suggesting that MLBNs receive glycinergic inhibition of non-OPN origin as well. We conclude that glycinergic inhibition plays essential roles in the maintenance of stable fixation, the termination of saccades, and the regulation of saccade size and velocity.

Effects of bosentan on the skin lesions: an observational study from a single center in Japan

Effects of a dual endothelin receptor antagonist, bosentan on peripheral circulatioin and skin lesions as well as pulmonary arterial hypertension (PAH) were investigated in Japanese patients with connective tissue diseases (CTD). Fifteen patients with PAH associated with CTD [systemic sclerosis (SSc) 13, mixed connective tissue disease (MCTD) 2] were treated with bosentan for 40-96 weeks, and changes of exercise capacity (6-min walk distance and Borg's dyspnea scale), cardio-pulmonary hemodynamics (right ventricular pressure, specific activity scale and cardiac index), Raynaud's phenomenon, digital ulcers and dermal sclerosis were observed. Bosentan improved exercise capacity, had a positive effect on hemodynamic parameters, and was well tolerated as previously reported. After a median 8 weeks of treatment, 13 out of 15 patients had improved Raynaud's phenomenon. Digital ulcers also improved after a median 12 weeks' treatment in all of 8 patients. Modified Rodnan total skin score decreased from 21.0 +/- 5.9 to 11.5 +/- 3.9 in diffuse cutaneous SSc and from 17.0 +/- 6.5 to 9.5 +/- 4.5 in limited cutaneous SSc after 24 months' treatment, reaching significance after 6 months in both groups. These data suggest that bosentan is effective for both PAH and peripheral vascular diseases in Japanese patients with CTD. The pathological background to the improvement in dermal sclerosis observed in this study should be further investigated.

Glycinergic inputs cause the pause of pontine omnipause neurons during saccades

Pontine omnipause neurons (OPNs) are inhibitory neurons projecting to saccade-related premotor burst neurons. OPNs exhibit sustained discharge during fixations and cease firing before and during saccades. The pause in OPN discharge releases the burst neurons from tonic inhibition, resulting in generation of saccadic eye movements. OPNs are thought to receive two major inhibitory inputs during saccades: an early component that determines the pause onset and a late component that controls the pause duration. Although there is evidence that numerous glycinergic and GABAergic terminals contact OPNs, their physiological roles remain unclear. To reveal functions of glycinergic and GABAergic inputs, we investigated effects of iontophoretic application of strychnine, a glycine receptor antagonist, and bicuculline, a GABAA receptor antagonist, on discharge patterns of OPNs in alert cats. Application of strychnine reduced the ratio of pause duration to saccade duration. Analysis of the timing of pause relative to saccades showed that pause onset was delayed and pause end was advanced. These effects were observed for saccades in all directions. Application of bicuculline, in contrast, had no effect on the OPN pause duration or timing. Both strychnine and bicuculline increased tonic firing rate during intersaccadic intervals. These results suggest that glycinergic, but not GABAergic, afferents convey inhibitory signals that determine the onset as well as duration of pause in OPN activity during saccades.

Activity-dependent conduction block in multifocal motor neuropathy: Magnetic fatigue test

BACKGROUND

Multifocal motor neuropathy (MMN) is often misdiagnosed as motor neuron disease, especially when overt evidence of conduction block (CB) is lacking. Activity-dependent CB (ADCB), defined as transient CB induced by brief exercise, has been recently found in MMN but not in ALS.

METHODS

To test the diagnostic utility of ADCB for differentiating MMN from ALS, the authors recorded the compound muscle action potentials (CMAPs) from small hand muscles by magnetically stimulating nerve roots before and after 1 minute of maximal voluntary contraction (magnetic fatigue test). They examined nine patients with MMN with unequivocal clinical responses to IV immunoglobulins (IVIgs), yet lacked CB according to the conventional criteria.

RESULTS

Six MMN patients had postexercise CB/temporal dispersion maximum in the immediate postexercise period. ADCB in an MMN patient improved after IVIg. Further analysis revealed that prolongation of the duration from the onset to the positive peak of the CMAP was the most sensitive indicator for MMN, presumably because the phase cancellation obscures the abnormalities of the other parameters.

CONCLUSION

The magnetic fatigue test is useful in detecting mild conduction block presumably located in a proximal nerve segment in patients with multifocal motor neuropathy who do not fulfill its conventional electrodiagnostic criteria.

Macaque ventral premotor cortex exerts powerful facilitation of motor cortex outputs to upper limb motoneurons

The ventral premotor area (F5) is part of the cortical circuit controlling visuomotor grasp. F5 could influence hand motor function through at least two pathways: corticospinal projections and corticocortical projections to primary motor cortex (M1). We found that stimulation of macaque F5, which by itself evoked little or no detectable corticospinal output, could produce a robust modulation of motor outputs from M1. Arrays of fine microwires were implanted in F5 and M1. During terminal experiments under chloralose anesthesia, single stimuli delivered to M1 electrodes evoked direct (D) and indirect (I1,I2, and I3) corticospinal volleys. In contrast, single F5 shocks were ineffective; double shocks (3 msec separation) evoked small I waves but no D wave. However, when the test (T) M1 shock was conditioned (C) by single or double F5 shocks, there was strong facilitation of I2 and I3 waves from M1, with C-T intervals of <1 msec. Intracellular recordings from 79 arm and hand motoneurons (MNs) revealed no postsynaptic effects from single F5 shocks. In contrast, these stimuli produced a robust facilitation of I2 and I3 EPSPs evoked from M1 (60% of MNs); this was particularly marked in hand muscle MNs (92%). Muscimol injection in M1 reduced I waves from F5 and abolished the F5-induced facilitation of late I waves from M1, and of EPSPs associated with them. Thus, some motor effects evoked from F5 may be mediated by corticocortical inputs to M1 impinging on interneurons generating late corticospinal I waves. Similar mechanisms may allow F5 to modulate grasp-related outputs from M1.

Facilitation from ventral premotor cortex of primary motor cortex outputs to macaque hand muscles

We demonstrate that in the macaque monkey there is robust, short-latency facilitation by ventral premotor cortex (area F5) of motor outputs from primary motor cortex (M1) to contralateral intrinsic hand muscles. Experiments were carried out on two adult macaques under light sedation (ketamine plus medetomidine HCl). Facilitation of hand muscle electromyograms (EMG) was tested using arrays of fine intracortical microwires implanted, respectively, in the wrist/digit motor representations of F5 and M1, which were identified by previous mapping with intracortical microstimulation. Single pulses (70-200 microA) delivered to F5 microwires never evoked any EMG responses, but small responses were occasionally seen with double pulses (interval: 3 ms) at high intensity. However, both single- and double-pulse stimulation of F5 could facilitate the EMG responses evoked from M1 by single shocks. The facilitation was large (up to 4-fold with single and 12-fold with double F5 shocks) and occurred with an early onset, with significant effects at intervals of only 1-2 ms between conditioning F5 and test M1 stimuli. A number of possible pathways could be responsible for these effects, although it is argued that the most likely mechanism would be the facilitation, by cortico-cortical inputs from F5, of corticospinal I wave activity evoked from M1. This facilitatory action could be of considerable importance for the coupling of grasp-related neurons in F5 and M1 during visuomotor tasks.

A model for predicting sediment-water partition of toxic chemicals in aquatic environments

In order to investigate the characteristics of sediment-water partition of chemicals in aquatic environments using published data, we developed a model for predicting the sediment-water partition coefficient (Kp) as the sum of sorption to sediment organic matter and sorption to sediment inorganic matter. This model is so successful that the differences between Kp (median for a variety of Japanese water bodies) and pre-Kp (predicted K) are within one order of magnitude in 24 out of 28 chemicals.

Disynaptic inhibition of omnipause neurons following electrical stimulation of the superior colliculus in alert cats

We investigated the synaptic organization responsible for the inhibition of omnipause neurons (OPNs) following stimulation of the superior colliculus (SC) in alert cats. Stimulation electrodes were implanted bilaterally in the rostral and caudal SC where a short-pulse train induced small and large saccades, respectively. Effects of single-pulse stimulation on OPNs were examined with intracellular and extracellular recordings. In contrast to monosynaptic excitatory postsynaptic potentials, which were induced by rostral SC stimulation, inhibitory postsynaptic potentials were induced with disynaptic latencies (1.3--1.9 ms) from both the rostral and caudal SC in most OPNs. Analysis of a larger extracellular sample complemented intracellular observations. Monosynaptic activation of OPNs was elicited more frequently from rostral sites than from caudal sites, whereas spike suppression with disynaptic latencies was induced by caudal as well as rostral stimulation with similar frequencies. The results imply that disynaptic inhibition is produced by activation of SC cells that are distributed over wide regions related to saccades of different sizes. We suggest that signals from these neurons initiate a saccadic pause of OPNs through single inhibitory interneurons.

DYT1 mutation in Japanese patients with primary torsion dystonia

A GAG deletion at position 946 in the DYT1 gene has been identified as one of the gene mutations responsible for autosomal dominant primary torsion dystonia. We examined 178 Japanese patients with various forms of dystonia, and found the mutation in six patients (3.4%) from three families. Five of them had early clinical onset (before age 12) with initial involvement of a limb. To our knowledge, this is the first report of the frequency and the clinical features of DYT1 mutation in oriental patients, and the clinical presentation of the mutation in these patients was similar to that of Jewish or non-Jewish Caucasian patients.

Abnormal premovement gating of somatosensory input in writer's cramp

One characteristic of focal dystonia is the sensory trick, by which sensory input to a certain area of the body can reduce abnormal contractions in muscles nearby. This suggests that adjusting the link between sensory input and movement allows motor commands to be issued more effectively from the brain. To explore this sensorimotor link, we studied the attenuation (gating) of somatosensory evoked potentials (SEPs) before and during hand movements in patients with writer's cramp. For premovement gating, 10 patients and 11 age-matched normal subjects were given a warning sound followed 1s later by an electric stimulus to the right median nerve at the wrist. The latter served both as a reaction signal to start a finger extension task and as the input to evoke SEPs over the scalp. Because reaction times always exceeded 70 ms, short-latency SEPs thus obtained were unaffected by the afferents activated by the movement. The amplitudes of frontal N30 components were significantly decreased over the frontal leads compared with SEPs elicited at rest (P: < 0.002) in the normal group, whereas significant gating was found not for N30 but for frontal P22 (P: = 0. 002) in the patient group. For midmovement gating studies, SEPs to the right median nerve stimulation were recorded in 16 patients and 12 age-matched normal subjects at rest, and during active and passive finger extension-flexion movements. In contrast to the premovement SEPs, the frontal N30 was equally gated during active and passive movements both in the patient (P: < or = 0.002) and the normal group (P: < or = 0.003). These findings indicate that in writer's cramp the sensitivity of sensory input channels from the hand is wrongly set by the central command to move. Perhaps the sensory trick, by supplying additional input not usually present during unobstructed movement, is a manoeuvre to correct this imbalance. Dystonia may result not only from abnormalities in the central motor command but also from disturbed central processing of sensory input.

High-frequency SEP components generated in the somatosensory cortex of the monkey

To investigate the origin of high-frequency somatosensory evoked potential (SEP) components, we recorded median nerve SEPs from the scalp and the depth in six monkeys. Laminar field potentials were analyzed in area 3b (N10; corresponding to human N20) and area 1 (P12; corresponding to human P25). After digital filtering (300-900 Hz), 4-6 components were identified, and the 1st to 4th peaks in area 3b (7-11 ms in latency) and the 3rd to 5th in area 1 (9-13 ms) showed clear polarity reversals between the surface and the depth of the cortex. These results provide direct evidence for intracortical origin of early high-frequency components in area 3b and of late ones in area 1.

Saccade-related inhibitory input to pontine omnipause neurons: an intracellular study in alert cats

Omnipause neurons (OPNs) are midline pontine neurons that are thought to control a number of oculomotor behaviors, especially saccades. Intracellular recordings were made from OPNs in alert cats to elucidate saccade-associated postsynaptic events in OPNs and thereby determine what patterns of afferent discharge impinge on OPNs to cause their saccadic inhibition. The membrane potential of impaled OPNs exhibited steep hyperpolarization before each saccade that lasted for the whole period of the saccade. The hyperpolarization was reversed to depolarization by intracellular injection of Cl- ions, indicating it consisted of temporal summation of inhibitory postsynaptic potentials (IPSPs). The duration of the saccade-related hyperpolarization was almost equal to the duration of the concurrent saccades. The time course of the hyperpolarization was similar to that of the radial eye velocity except for the initial phase. During the falling phase of eye velocity, the correlation between the instantaneous amplitude of hyperpolarization and the instantaneous eye velocity was highly significant. The amplitude of hyperpolarization at the eye velocity peak was correlated significantly with the peak eye velocity. The time integral of the hyperpolarization was correlated with the radial amplitude of saccades. The initial phase disparity between the hyperpolarization and eye velocity was due to the relative constancy of peak time (approximately 20 ms) of the initial steep hyperpolarization regardless of the later potential profile that covaried with the eye velocity. The initial steep hyperpolarization led the beginning of saccades by 15.9 +/- 3.8 (SD) ms, which is longer than the lead time for medium-lead burst neurons. These results demonstrate that the pause of activity in OPNs is caused by IPSPs initiated by an abrupt, intense input and maintained, for the whole duration of the saccade, by afferents conveying eye velocity signals. We suggest that the initial sudden inhibition originates from central structures such as the superior colliculus and frontal eye fields and that the eye velocity-related inhibition originates from the burst generator in the brain stem.

Pre-movement gating of short-latency somatosensory evoked potentials

Somatosensory evoked potentials (SEPs) are reduced in amplitude during movement (gating). The mechanism involves central gating of afferent input and competition from other afferents activated by the movement. We distinguished these two by giving 11 normal subjects a warning sound followed 1 s later by an electric stimulus to the right median nerve at the wrist. The latter served both as a cue to start a finger movement and as stimulation to evoke SEPs. Gating effects were widespread in frontal (N30) and central (N60) areas, but were also seen, albeit to a lesser extent, in the recordings at P3 (P30). Since finger movement began after the stimulus, such gating must have been purely central in origin, presumably reflecting motor preparation.

Vascular tone in patients with hemorrhagic shock

BACKGROUND

In hemorrhagic shock, the alterations in arterial vascular tone, which are primarily regulated by adrenosympathetic influences are compensatory responses to bleeding.

OBJECTIVE

The aim of this study was to evaluate vascular tone expressed by the volume elastic modulus (Ev) as a clinical monitor to detect the hypovolemic state.

METHODS

Thirteen patients with hemorrhagic shock were studied. The initial Ev measurement was performed at arrival, and subsequent measurements were obtained 4 and 12 hours after arrival. Patients were divided into two groups by cluster analysis by using the Ev values at arrival and 4 hours after arrival. Circulatory parameters, the clinical course, and fluid were compared.

RESULTS

The Ev values were identical at admission (cluster I vs. II: 456.4+/-197.1 vs 566.1+/-234.1 mm Hg, mean +/- SD). After 4 hours of fluid resuscitation, all patients were recovered from shock. In cluster I, the Ev remained high at 4 hours (523.4+/-75.1 mm Hg) and invasive treatments for hemostasis were required. In cluster II, the Ev significantly decreased at 4 hours (182.8+/-70.7 mm Hg, p < 0.01) and clinical courses were eventless thereafter. During 4 to 12 hours, more fluid was given in cluster I (p < 0.05). At 12 hours after arrival, the Ev values were identical in both clusters.

CONCLUSION

These data demonstrate that the Ev increases in hemorrhagic shock. Furthermore, normotensive hypovolemic conditions generated by persistent bleeding can be detected by measuring the Ev.

Reproductive toxicity, mutagenicity and antigenicity of pamiteplase (genetical recombination)

Pamiteplase (genetical recombination), YM866, is a novel recombinant modified human tissue-type plasminogen activator developed by Yamanouchi Pharmaceutical Co. Ltd., Tokyo, Japan. An intended route of administration in the clinical use of this drug is intravenous administration. We conducted an intravenous fertility and general reproduction studies of this drug in male and female rats and teratology study of this drug in rabbits at the dose levels of 0 (vehicle control), 0.1, 0.3 or 1 mg/kg/day. In the rat, no treatment-related abnormalities were observed up to the maximum dose in parental animals and their offspring. In the teratology study in rabbits, prolonged coagulation time at the injection site was observed at 0.3 mg/kg or more. One death and one abortion occurred at 1 mg/kg on days 22 and 23 of pregnancy, respectively. No toxic effects on the litters were observed up to the maximum dose. Results of evaluation of the mutagenicity of YM866 and its ability to induce chromosome aberrations using the L5178Y TK+/- mouse lymphoma assay, human lymphocyte chromosome aberration assay and the micronucleus assay in mice were negative. Evaluation of the immunogenicity of YM866 by repeated intravenous injection in chimpanzees elicited no confirmed antibody titers.

The community health center and family practice residency training

Community health centers (CHCs), sponsored by US Public Health Service (USPHS) Section 330, represent successful models of the application of community-oriented primary care principles. Recently, increased interest has been shown in conducting medical education programs in CHCs. The USPHS has tried to facilitate this interest, particularly through its support of establishing linkages between CHCs and family practice residency programs. In this paper, we describe an integrated CHC-family practice residency continuity training clinic program. We discuss the challenges inherent to conducting family practice residency training in the CHC, including the educational content of clinical experiences, the impact of provider productivity expectations, the academic and operational governance of the program, and the financial considerations pertinent to the integrated function of the program. We conclude that while the clinical experiences available in the CHC differ somewhat from mainstream family practice, successful adaptations can be made, and a CHC offers a rich educational environment. We also conclude that the challenges inherent to integrated CHC-family practice residency programs can be successfully addressed. Of great concern, however, are financial considerations relevant to the operation of such integrated programs. These considerations underscore the urgent need for a reassessment of the funding of ambulatory clinical medical education.

Monosynaptic activation of medium-lead burst neurons from the superior colliculus in the alert cat

1. Extracellular recordings were made from medium-lead burst neurons (MLBNs) in the paramedian pontomedullary reticular formation rostral and caudal to the abducens nucleus in the alert cat. 2. Single-pulse stimulation of the contralateral superior colliculus during intersaccadic intervals evoked no response in most MLBNs. When collicular stimulation was applied at the beginning of saccades, spikes of MLBNs were consistently evoked with short latencies. The shortest latency was 0.8 ms, indicating monosynaptic activation of MLBNs from the superior colliculus. 3. Results suggest that monosynaptic excitatory effects from the colliculus are concealed by inhibitory input from omnipause neurons (OPNs) during intersaccadic intervals and that the monosynaptic collicular activation is disclosed when this inhibition is removed by a pause in OPN activity at the beginning of saccades.

[Single-dose toxicity studies of prulifloxacin (NM441) in mice, rats and dogs and the active metabolite (NM394) in rats]

Single-dose toxicity studies of prulifloxacin, a new antibacterial agent, were conducted in mice, rats and dogs. In addition, a single-dose toxicity study of (+/-)-6-fluoro-1-methyl-4-oxo-7- (1-piperazinyl)-4H-[1,3]thiazeto[3,2-a]quinoline- 3-carboxylic acid (NM394), an active metabolite of prulifloxacin, was performed in rats. Prulifloxacin was administered orally, intraperitoneally (i.p.) or subcutaneously (s.c.) to mice and rats, and orally to dogs. NM394 was administered intravenously (i.v.) to rats. When prulifloxacin was administered orally or s.c., LD50 values were more than 5000 mg/kg in both sexes of mice and rats; when it was administered i.p., LD50 values were 1757 mg/kg in male mice, 1652 mg/kg in female mice, 915 mg/kg in male rats, and 1076 mg/kg in female rats. The lethal doses of this drug were more than 5000 mg/kg in both sexes of dogs by the oral route. The LD50 values of NM394 were 226 mg/kg in male rats and 238 mg/kg in female rats by the i.v. route. In mice, the major clinical signs observed following the administration of prulifloxacin were sedation, oligopnea, abnormal gait, piloerection, closed eye and tremor by the i.p. route and a scab at the site of injection by the s.c. route; in rats, decreased spontaneous locomotor activity by any of the three routes, oligopnea, lacrimation, hypothermia, piloerection and abnormal gait by the i.p. route, and a scab at the site of injection by the s.c. route; and in dogs, vomiting, reddening of the skin, and loose stool by the oral route. When NM394 was administered i.v., rats showed clonic convulsion and dyspnea. The site of injection was hyperemic, swollen and necrotic. Mice showed a decrease in body weight or an inhibition in weight gain when prulifloxacin was administered i.p. and rats showed the same effects when prulifloxacin or NM394 was administered by any of the above-mentioned routes. Macroscopic findings detected following the i.p. administration of prulifloxacin in mice were pale color of the liver and spleen, thickening of the liver, and adhesion of intra-abdominal organs; and in rats, hydrothorax, congestion and edema of the lung, adhesion of intra-abdominal organs, swelling of the kidney accompanied by fine yellowish-white foci, and atrophy of the testis. When NM394 was administered i.v. to rats, congestion of the lung was macroscopically observed.

Inhibitory input to pause neurons from pontine burst neuron area in the cat

Extra- and intracellular recordings were made from pontine pause neurons (PNs) in the cat. Spontaneous spikes of PNs were suppressed after single shock stimulation of excitatory burst neuron (EBN) area immediately rostral to the abducens nucleus. The most effective stimulation site for the suppression was the region where long-lead burst neurons (LLBNs) were predominantly located. Intracellular recordings from PNs showed that stimulation of the LLBN area induced short-latency inhibitory postsynaptic potentials (IPSPs) in PNs and that steep hyperpolarization of PNs associated with quick phases of nystagmus occurred prior to an abrupt change in abducens nerve activity. Results suggest that a pause of PN spikes associated with quick phases is, at least in part, produced by inhibitory action mediated through LLBNs.

Synthetic studies on condensed-azole derivatives. IV. Synthesis and anti-asthmatic activities of omega-sulfamoylalkyloxyimidazo[1,2-b]pyridazines

A series of novel (imidazo[1,2-b]pyridazin-6-yl)oxyalkylsulfonamides was synthesized and evaluated for the ability to inhibit platelet activating factor (PAF)-induced bronchoconstriction in guinea pigs. The compounds bearing a gem-dialkyl or a cycloalkylidene group at the 2 position of the sulfamoylpropyloxy group in the side chain were found to have potent activity. Among them, 3-(imidazo[1,2-b]pyridazin-6-yl)oxy-2,2-dimethylpropanesulfonam ide (6) showed excellent anti-asthmatic activity and the longest duration of action. The compounds bearing a methyl group at the 7 or 8 position of the imidazo[1,2-b]pyridazine ring were found to have enhanced activity. Among them, 3-(7-methylimidazo[1,2-b]pyridazin-6-yl)oxy-2,2- dimethylpropanesulfonamide (25) showed the most potent inhibitory effect, and its anti-asthmatic effect in an experimental model of allergic asthma was superior to that of theophylline. The structure-activity relationships in this series of compounds are discussed.

Functional connectivity of the superior colliculus with saccade-related brain stem neurons in the cat

Effects of stimulation of the superior colliculus on saccade-related brain stem neurons were studied in the alert cat. Extracellular recordings were made from medium-lead burst neurons (MLBNs), omnipause neurons (OPNs) and burster-driving neurons (BDNs) in the paramedian pontomedullary region rostral and caudal to the abducens nucleus. MLBNs were activated from the contralateral superior colliculus with monosynaptic latencies when single-pulse stimulation was given during saccades or ipsilateral head rotation, although this activation was not observed during fixation periods. The caudal SC was more effective than the rostral SC in monosynaptic activation of MLBNs. Most OPNs were also activated monosynaptically from the SC. In contrast to MLBNs, the activation of OPNs was more frequently induced from the rostral SC than from the caudal SC. Stimulation of the caudal SC often induced suppression of spikes in OPNs. BDNs received excitation from the ipsilateral SC through a di- or trisynaptic pathway. Like MLBNs, BDNs tended to receive stronger input from the caudal SC than the rostral SC. Results indicate the existence of tectofugal excitatory pathways to MLBNs and BDNs and an inhibitory pathway to OPNs. It seems likely that these pathways originate from saccade-related burst cells in the SC. Since excitation of BDNs and inhibition of OPNs increase the excitability of MLBNs, all of these pathways may contribute to burst activity in MLBNs and thereby saccade generation. Results also support the current idea that cells in the rostral SC may participate in fixation by activating OPNs.

[Comparison of CAF plus MPA with CAF plus TAM for advanced or recurrent breast cancer--Kyushu CAFT Study Group of Advanced or Recurrent Breast Cancer]

A multi-center randomized comparison study of CAF + TAM therapy (Arm A) and CAF + MPA therapy (Arm B) in advanced or recurrent breast cancer was conducted at 37 institutions in Kyushu. Out of 119 registered cases, 114 were eligible and 76 were evaluable. The response rate was 42% (15/36) in Arm A and 58% (23/40) in Arm B. In the comparison of side effects, nausea/vomiting and anorexia were significantly less and moon face and body weight gain were significantly more in Arm B. Leucocytopenia was significantly inhibited in Arm B compared with Arm A, which indicated the myeloprotective effect of MPA. These results indicated that CAF + MPA therapy (Arm B) may be more advantageous than CAF + TAM therapy (Arm A) in advanced or recurrent breast cancer.

Synthetic studies on condensed-azole derivatives. III. Synthesis and anti-asthmatic activities of C-substituted alkyl side chain derivatives of omega-sulfamoylalkylthioimidazo[1,2-b]pyridazines and related compounds

A series of novel alkylthioimidazo[1,2-b]pyridazines was synthesized and evaluated for ability to inhibit platelet activating factor (PAF)-induced bronchoconstriction in guinea pigs. Among them, 3-(imidazo[1,2-b]pyridazin-6-yl)thio-2,2-dimethylpropanesulfona mide (15) showed the most potent inhibitory effect. The structure-activity relationships in this series of compounds, in particular, the effects of conversion of the imidazopyridazine ring into other heterocyclic rings, introduction of a substituent group at the 2 or 3 position of the imidazopyridazine ring and introduction of a substituent group into the alkyl side chain, are also discussed.

Site of interaction between saccade signals and vestibular signals induced by head rotation in the alert cat: functional properties and afferent organization of burster-driving neurons

1. Extracellular spikes of burster-driving neurons (BDNs) were recorded within and immediately below the prepositus hypoglossi nucleus in the alert cat. BDNs were characterized by short-latency activation after stimulation of the contralateral vestibular nerve (latency: 1.4-2.7 ms) and the ipsilateral superior colliculus (latency: 1.7-3.5 ms). Convergence of vestibular and collicular inputs was found in all of 85 BDNs tested. Firing of BDNs increased during contralateral horizontal head rotation and decreased during ipsilateral rotation. A burst of spikes was induced in association with contralateral saccades and quick phases of nystagmus. 2. BDNs showed irregular tonic discharges during fixation. There was no significant correlation between the firing rate during fixation and horizontal or vertical eye position in most BDNs. During horizontal sinusoidal head rotation, the change in firing rate was approximately proportional to and in phase with contralateral head velocity. The phase lag of the response relative to head angular velocity was 13.8 +/- 20.1 degrees (mean +/- SD) at 0.5 Hz and 7.2 +/- 13.5 degrees at 0.2 Hz on the average. The gain was 0.88 +/- 0.25 (spikes/s)/(degrees/s) at 0.5 Hz and 1.19 +/- 0.49 (spikes/s)/(degrees/s) at 0.2 Hz. 3. Quantitative analysis of burst activity associated with saccades or quick phases indicated that the ON direction of BDNs was contralateral horizontal. The number of spikes in the burst was linearly related to the amplitude of the contralateral component of rapid eye movements. The slope of regression line was, on the average, 1.14 +/- 0.48 spikes/deg. There was no significant difference between the mean slopes for saccades and quick phases. The number of spikes depended on the difference between initial and final horizontal eye positions and not on the absolute eye position in the orbit. The mean burst firing rate was proportional to the mean velocity of the contralateral component of rapid eye movements. The slope of the regression line was 0.82 +/- 0.34 (spikes/s)/(degrees/s). Significant correlation was also found between intraburst instantaneous firing rate and instantaneous component eye velocity. 4. Objects presented in the contralateral visual field elicited a brief burst of spikes in BDNs independent of any eye movement. Contralateral saccades to the target were preceded by an early response to the visual stimulus and subsequent response associated with eye movement. 5. Excitation of BDNs produced by stimulation of the ipsilateral superior colliculus was facilitated by contralateral horizontal head rotation. Therefore saccadic signals from the superior colliculus to BDNs may be augmented by vestibular signals during head rotation.(ABSTRACT TRUNCATED AT 400 WORDS)

Plasma catecholamine and cortisol concentrations during acceleration stress

Serial changes in catecholamine (CA) and cortisol (Col) concentrations of human subjects exposed to acceleration stress with the vector in the head-foot direction (+ 5Gz for 1 min) were determined using a newly designed continuous blood sampling system. The results demonstrated that the time course changes in noradrenaline (NA), adrenaline (A) and Col concentrations were quite different from each other during and after the Gz exposure. The NA remained relatively unchanged during the exposure, and showed a marked increase at the end of the exposure, peaking at about 110 s after the end of the exposure. The A showed a gradual increase from the start of the exposure and continued to rise during and after the exposure. Its maximal peak was also found at about 110 s after the exposure. The A showed a sevenfold increase, while NA showed only about a threefold increase as high as pre-exposure levels. The more rapid and greater magnitude of increase in A concentration during exposure may have reflected the larger emotional stress and strenuous physical activities involved in the Gz exposure. Heart rate showed a rapid increase upon exposure and remained significantly increased during the exposure; it then showed a transient fall immediately after the exposure, despite the increase in CA. An interesting observation was a decrease in Col during the Gz exposure. A plausible explanation would appear to be the result of an enhanced rate of Col removal from the plasma. From these observations, the importance of serial determination of hormonal excretion during Gz stress for the precise analysis of hormonal response to Gz stress was confirmed.

Occult lymph node metastasis in gastric cancer with submucosal invasion

To evaluate more precisely the incidence of lymph node metastasis in patients with submucosally invaded (sm) gastric cancer, three additional sections were made from the remaining half of 1,794 lymph nodes taken from 57 patients, for a detailed reexamination. Lymph node metastasis was demonstrated in 19 nodes from 11 patients by the initial routine examination; however, the detailed reexamination showed cancer involvement in a further nine lymph nodes from eight patients. Of these eight patients, metastasis had not been detected in any lymph nodes by routine examination in six. Macroscopically, the lesion was of the depressed or mixed type in six of the eight patients. From the intranodal location and growth pattern of the cancer foci, lymph nodes with occult metastasis were divided into the marginal sinus type, the medullary sinus type, and the mixed type, with the marginal type being found most frequently. The overall incidence of lymph node metastasis in patients with sm gastric cancer was as high as 29.8% (17/57) in this series. Moreover, a follow-up study revealed that two patients with occult metastasis died of cancer recurrence postoperatively. Accordingly, systematic regional lymph node dissection should be carried out at the time of surgery for sm gastric cancer.

Inhibition of the increase of intrahepatic Ca2+ by diltiazem in rats with liver ischemia

The effects of a continuous infusion of a calcium entry blocker, 1, 5-benzothiazepine derivative (diltiazem), on ischemic liver cell damage were studied using quantitative 45Ca-autoradiographic and liquid scintillation techniques. The drug was administered to male Wistar rats as a continuous infusion for 3 h, beginning 30 min before ischemia. Autoradiographic studies showed that 45Ca accumulated in the liver lobuli after 1 h of liver ischemia and 3 h of reperfusion, but the level of 45Ca accumulation was significantly lower in drug-treated rats than in untreated animals. In addition, liquid scintillation studies showed significant differences in the intrahepatic 45Ca contents. These results suggest that diltiazem may inhibit the rise of intracellular Ca2+ due to the flow of extracellular Ca2+ into the cytosol, and may protect the ischemic liver from damage.

Electrical admittance cuff for noninvasive and simultaneous measurement of haematocrit, arterial pressure and elasticity using volume-oscillometric method

An improved technique based on the electrical admittance cuff was designed for the non-invasive measurement of haematocrit (Hct), together with blood pressure (BP) and arterial elasticity represented as volume elastic modulus (Ev), in human fingers. This device is made of a rigid annular chamber installed with a surrounding thin-walled tube (cuff), which is filled with electrolyte solution. A tetrapolar method is used to detect the admittance signals, both in the solution and in a finger segment placed through the cuff. With this device, it is theoretically shown that the resistivity of blood flowing into the segment is equal to that of the solution multiplied by the ratio of the admittance variation in the solution to that in the segment. Thus, the blood resistivity and therefore Hct can be non-invasively determined from the electrolyte resistivity and these two admittance variations. On the other hand, BP and Ev are also simultaneously measured from the admittance signals following the gradual change of the chamber pressure based on the volume-oscillometric method. Experiments were successfully made in 14 subjects, showing that the indirect Hct values agreed well with the direct values obtained from sampled blood and that this simple technique was significant for the non-invasive ad simultaneous measurement of these physiological variables.

Hepatocyte growth factor prevents acute renal failure and accelerates renal regeneration in mice

Although acute renal failure is encountered with administration of nephrotoxic drugs, ischemia, or unilateral nephrectomy, there has been no effective drug which can be used in case of acute renal failure. Hepatocyte growth factor (HGF) is a potent hepatotropic factor for liver regeneration and is known to have mitogenic, motogenic, and morphogenic activities for various epithelial cells, including renal tubular cells. Intravenous injection of recombinant human HGF into mice remarkably suppressed increases in blood urea nitrogen and serum creatinine caused by administration of cisplatin, a widely used antitumor drug, or HgCl2, thereby indicating that HGF strongly prevented the onset of acute renal dysfunction. Moreover, exogenous HGF stimulated DNA synthesis of renal tubular cells after renal injuries caused by HgCl2 administration and unilateral nephrectomy and induced reconstruction of the normal renal tissue structure in vivo. Taken together with our previous finding that expression of HGF was rapidly induced after renal injuries, these results allow us to conclude that HGF may be the long-sought renotropic factor for renal regeneration and may prove to be effective treatment for patients with renal dysfunction, especially that caused by cisplatin.

Long-term results of subtotal esophagectomy with three-field lymphadenectomy for carcinoma of the thoracic esophagus

OBJECTIVE

This study evaluated the impact of aggressive surgery on survival in patients with carcinoma of the thoracic esophagus.

SUMMARY BACKGROUND DATA

Prognostic value of lymph-node status for patients with esophageal carcinoma was emphasized, although it is currently under debate whether extensive lymph node dissection improves survival.

METHODS

Two hundred ninety-five patients with thoracic esophageal carcinoma were admitted to Kagoshima University Hospital from December 1982 to December 1990. Esophagectomy was performed on 244 (82.7%) of these patients; 106 of whom underwent three-field lymphadenectomy (bilateral cervical, mediastinal, and abdominal regions) were analyzed regarding lymph-node status, tumor recurrence, and the effect of prognostic factors on survival using Cox's proportional hazards model.

RESULTS

Hospital mortality and morbidity were 10.4% (11/106) and 65.1%, respectively. Seventy-eight patients (73.6%) had nodal involvement, including 49 patients with abdominal lymph-node metastases and 46 patients with recurrent nerve-node metastases. Five-year survival rates were 54.5% for 16 patients with a solitary nodal metastasis, 30.3% for stage III, 17.4% for stage IV, and 7.2% for 28 patients with six or more metastatic nodes. The most frequent sites of recurrence were the upper mediastinal region and the lung--its incidence increased significantly as the number of positive nodes increased. The most unfavorable prognostic factors included regional or recurrent nerve-node metastasis and patient age of more than 71 years.

CONCLUSIONS

Three-field lymphadenectomy, including especially the removal of bilateral recurrent nerve nodes in the cervical region, is essential for improving the survival of patients with carcinoma of the upper two thirds of the thoracic esophagus.

[Significance of preservation of tracheal proper sheath at the time of cervical and upper mediastinal lymph node dissection for thoracic esophageal cancer]

Extended lymph node dissection in the neck and upper mediastinum often brings about postoperative pulmonary complications. Since September 1987, we have performed this type of lymph node dissection in 18 patients paying special attention to the preservation of tracheal proper sheath along with left bronchial artery and autonomic nerve branches. We compared their postoperative respiratory and circulatory outcomes with those of 17 patients in whom lymph node dissection was carried out without consideration for these aspects. Tracheal mucosal damage, respiratory functional parameters such as PaO2, AaDO2 and Qs/Qp and actual incidence of pneumonia significantly improved in recent cases undergoing meticulous dissection in the neck and upper mediastinum. However, neither circulatory dynamics nor incidences of recurrent nerve palsy and arrhythmia showed a significant improvement. The postoperative period required for reappearance of cough reflex was shorter in this group of patients, but the difference was not significant. The results indicated that pulmonary disorders occurring frequently after extended lymph node dissection for thoracic esophageal cancer was able to be well controlled by meticulous dissection procedure as mentioned above.