Response of patients with major depression and silent cerebral infarction to antidepressant drug therapy, with emphasis on central nervous system adverse reactions

BACKGROUND AND PURPOSE

We previously found that silent cerebral infraction (SCI) is present in most patients older than 50 years with major depression. The present study was designed to clarify the response to antidepressant pharmacotherapy in patients with major depression associated with SCI.

METHODS

Using clinical charts, we retrospectively studied patients older than 50 years who were admitted for antidepressant drug therapy. Patients with bipolar affective disorder and those with focal neurological symptoms were excluded. All patients underwent magnetic resonance imaging and were classified as SCI-negative or SCI-positive. The SCI-positive group was subclassified into those with moderate SCI (either perforating area or cortical area) (n = 15) and those with severe SCI (both perforating and cortical areas) (n = 7). Duration of treatment in hospital and the incidence of central nervous system adverse reactions to the antidepressant drugs were compared between the two groups.

RESULTS

The duration of hospital treatment in patients with severe SCI was significantly longer than in those with moderate SCI (P < .01). The percentage of patients with adverse central nervous system reactions to antidepressant drugs was significantly higher in the SCI-positive group than in the SCI-negative group (P < .05). Patients with severe SCI had significantly more adverse reactions than those with moderate SCI (P < .05).

CONCLUSIONS

Depressed patients with severe SCI required longer hospital treatment and had more drug-related adverse reactions of the central nervous system. These findings suggest that the depression associated with severe SCI may be resistant to treatment.

[Tactile extinction following the cerebral sinus thrombosis. A study using event-related potentials]

We reported a 46-year-old woman in whom cerebral sinus thrombosis manifested itself in headache and weakness while she was on an oral estrogen preparation. The neurological examinations revealed monoparesis of the right upper extremity, hyperactive right deep tendon reflex and disturbance of the joint sense, stereognostic sense, two-point discrimination and skin writing sense in the right upper extremity, in addition to tactile extinction. Brain CT showed empty triangle sign. MRI revealed infarction near the left postcentral gyrus and thrombosis of right sigmoid sinus. In the MRA study, there was low signal intensity in the posterior portion of the superior sagittal sinus and right transverse sinus. Short latency SEP in upper extremity showed that the central conduction time was normal, while the amplitude of wave components after N20 was reduced on the right side. Both palms were given bilateral or unilateral pressure stimuli. When event-related potentials (ERP) were evoked, using bilateral stimuli as a rare target, and left unilateral stimuli as a non-target, the P 300 latency was prolonged to 450 msec but was restored to normal with the improvement of tactile extinction. These results seem to suggest that the tactile extinction is ascribable to a disturbance of recognition at the higher brain function level and that ERP can be a useful objective yardstick in the evaluation of extinction phenomenon.

Differential regulation of intracellular signaling systems by sodium fluoride in rat glioma cells

We investigated the rapid and slow effects of NaF on intracellular signaling systems such as Ca2+ homeostasis and cyclic GMP (cGMP) generation in rat glioma C6 cells, using the Ca2+-sensitive dye fura-2 and cGMP enzyme immunoassay. We found that the following: (a) NaF enhanced cGMP generation in a concentration-dependent manner. This enhancement was abolished by pretreatment with 100 microM BAPTA tetraacetoxymethal ester or in the presence of W-7 in a concentration-dependent manner. N G-Monomethyl-L-arginine (NMMA), a competitive inhibitor or nitric oxide synthase (NOS), also inhibited the NaF-induced generation of cGMP. These results suggest that NaF-induced cGMP generation occurs via a calcium/calmodulin- and NOS-dependent pathway. (b) The basal intracellular Ca2+ concentration ([Ca2+]i) was transiently greater at 1 and 3 h after pretreatment with NaF. W-7 and W-13 antagonized the increase in [Ca2+]i, whereas NMMA had little effect. This suggests that the NaF-induced change in basal [Ca2+] was mediated by a calmodulin-dependent pathway but was independent of a NOS-sensitive pathway. (c) The serotonin (5-HT)-induced intracellular mobilization of Ca2+ was reduced by pretreating the cells with NaF. The reduction in Ca2+ mobilization was antagonized by genistein, a tyrosine kinase inhibitor. W-7, W-5, and H-8 had no effect. Results suggest that NaF differentially regulated the cGMP generation. basal [Ca2+]i, and 5-HT2A receptor function in C6 glioma cells.

Predominant expression of human zic in cerebellar granule cell lineage and medulloblastoma

Zic is a novel zinc finger protein which displays a highly restricted expression pattern in the adult and developing mouse cerebellum and is highly homologous to the recently cloned Drosophila pair-rule gene Opa. To clarify the mechanism for the development of the human cerebellum and its involvement in human nervous system diseases, we have isolated human Zic cDNA and examined its expression by using monoclonal antibody against recombinant Zic protein. The nucleotide sequence of human Zic cDNA is 85% homologous to that of mouse Zic cDNA. Its putative amino acid sequence is highly conserved (> 99%) except for substitution of only two amino acid residues. In situ chromosome hybridization localized the human Zic gene to chromosome band 3q24. Human Zic protein was immunohistochemically detected in the nuclei of the cerebellar granule cell lineage from the progenitor cells of the external germinal layer to the postmigrated cells of the internal granular layer. Furthermore, Zic protein was detected in medulloblastoma (26/29 cases), whereas no other tumors examined (over 70 cases including primitive neuroectodermal tumors) expressed this protein. These findings suggest that Zic is a potential biomarker for medulloblastoma as well as the human cerebellar granule cell lineage.

Effect of interferon-alpha on DOI-induced wet-dog shakes in rats

Acute (1 h) intraperitoneal (i.p.) treatment with interferon (IFN)-alpha-2a (300 IU/g) significantly inhibited wet-dog shakes (WDS) induced by (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2 aminopropane (DOI; 0.5, 1.0 mg/kg), which is mediated by serotonin (5-hydroxytryptamine; 5-HT)2 receptor in rats. IFN-alpha did not affect spontaneous locomotion. The inhibition of DOI (0.5 mg/kg)-induced WDS by IFN-alpha was dose (90-300 IU/g)- and time (1-6 h)-dependent, and was prevented by 30 min pretreatment with naltrexone (NLTX; 1.0 mg/kg, i.p.), an opioid receptor antagonist. Acute (1 h) intracerebroventricular (i.c.v.) treatment with IFN-alpha (1,500 IU/rat) also inhibited DOI (0.5 mg/kg)-induced WDS, and the effect was blocked by NLTX (50 micrograms/rat, i.c.v.). These results suggest that IFN-alpha may modulate 5-HT2 receptor-mediated behavior through opioid receptors in the central nervous system.

[Mechanical ventilation and long-term respiratory care in the intensive care unit of a general hospital]

We studied the need for mechanical ventilation in 265 patients with respiratory failure who came to our medical ICU over the past 3 years. The time required for weaning from mechanical ventilation and the percentage of patients who needed oxygen therapy or mechanical ventilation at home after their condition was no longer acute were also studied. Of the patients treated in the medical ICU, 143 (54%) required mechanical ventilation; 104 (39%) had acute respiratory failure and the others had acute exacerbations of chronic respiratory failure. Some causes of acute respiratory failure were aspiration pneumonia, bronchial asthma, and drug use. Three-fourths of those with chronic respiratory failure had pulmonary emphysema, sequela of pulmonary tuberculosis, or idiopathic interstitial pneumonia. In patients with chronic respiratory failure, success in weaning could be predicted from the respiratory index (PaO2/FIO2), the serum albumin level, and the length of time that they were ventilated with more than 60% oxygen. Thirteen patients with chronic respiratory failure died while receiving mechanical ventilation. Of those who survived, 11 underwent tracheostomies, and 4 of those 11 were mechanically ventilated at home with portable devices. Ten other survivors received home oxygen therapy. Chest physicians bear the greatest responsibility for managing mechanical ventilation in medical emergencies. Moreover, the prognosis for patients with chronic respiratory failure can be improved with a long-term program for respiratory care that includes home mechanical ventilation and home oxygen therapy.

[Clinical and bacteriological effects of cefetamet pivoxil against community-acquired respiratory tract infections]

We investigated clinical and bacteriological effects of cefetamet pivoxil (CEMT-PI) in community-acquired respiratory tract infections and obtained the following findings. 1. Of the 420 respiratory tract infection cases that were treated with CEMT-PI according to a same protocol at a total of 42 institutions in Tokyo, Kanagawa-ken, Saitama-ken and Chiba-ken from February to the beginning of April 1994, 359 cases in which clinical evaluations were considered possible were selected as the subjects of the clinical study. Regarding genders of patients, slightly more females (56.3%) than males were included. Diagnoses given to these patients included laryngopharygealitis (60.7%), tonsillitis (14.2%) and acute bronchitis (13.6). Outpatients accounted for 94.4% of the subjects. 2. For the bacteriological study, a written material describing the method of collecting specimens, storage and transport in detail was distributed to the above mentioned institutions. The isolation and identification of suspected causative bacteria, determination of minimum inhibitory concentrations (MIC) and investigation of beta-lactamase production were conducted all together. Suspected causative bacteria were detected from 238 (66.3%) out of the 359 cases. They included 85 strains of Haemophilus influenzae, 76 strains of Streptococcus pneumoniae, 20 strains of Streptococcus pyogenes and 17 strains of Moraxella subgenus Branhamella catarrhalis. 3. Clinical efficacy rates (the ratio of those excellent+good) among those who were treated with 1 CEMT-PI tablet (194 mg, titer) twice a day was 76.5% and among those who were given 2 tablets twice a day was 87.4%. The improvement rate of the latter was higher at a significant level of P < 0.05. 4. The clinical efficacies classified by suspected causative bacteria (single bacterium) were 93.3% against M.(B.) catarrhalis, 91.7% against beta-streptococci, 87.1% against H. influenzae and 78.4% against S. pneumoniae, etc. Though 7 (9.2%) of the 76 strains of S. pneumoniae were benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP), the bacteriological efficacy was assessed either excellent or good in all of the 7 patients from whom PISP were detected. The clinical efficacy was assessed 100.0% in those from which a plural number of bacteria were detected. The 13 cases from which small numbers of Staphylococcus aureus was detected with other bacterium were also included in these cases.

[Antibacterial activities of cefmenoxime against recent fresh clinical isolates from patients in sinusitis]

In order to evaluate antimicrobial activity of cefmenoxime (CMX), minimum inhibitory concentrations (MICs) of CMX and control drugs were determined against clinical isolates from patients of sinusitis that were obtained in our laboratory from October of 1993 to March of 1994. The results are summarized as follows; 1. CMX showed strong antimicrobial activities against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella subgenus Branhamella catarrhalis that were 3 major aerobic bacteria from sinusitis. Antimicrobial activities of CMX against benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP) and PCG-resistant S. pneumoniae (PRSP) were stronger than those of ampicillin (ABPC), and these strong activities suggested that CMX might have strong antimicrobial activities against beta-lactamase producing H. influenzae and M. (B.) catarrhalis. 2. Antimicrobial activities of CMX against microaerophiles, Streptococcus constellatus, Streptococcus intermedius and Gemella morbillorum and against Peptostreptococcus spp., from chronic sinusitis and odontogenic maxillary sinusitis, were stronger than those of most of the control drugs. 3. The MIC90's of CMX against isolates from patients of sinusitis were < or = 0.025-0.39 micrograms/ml. These values were lower than transitional concentrations in mucous membrane of maxillary sinus obtained when "1% CMX nasal solution" was used with nebulizer. It appears likely that sufficient concentrations exceeding MICs against main organisms would be obtained by nebulizer treatment using CMX nasal solution.

Incidental Lewy body disease in a patient with REM sleep behavior disorder

We studied an 84-year-old man with a 20-year history of nocturnal violent behavior during sleep, but no other clinically evident neuropsychiatric disorders. Polysomnographic investigations confirmed that he suffered from REM sleep behavior disorder (RBD). Histopathologic examination revealed he had Lewy body disease with a marked decrease of pigmented neurons in the locus ceruleus and substantia nigra. These histologic findings represent the first documented evidence of a loss of brainstem monoaminergic neurons in clinically idiopathic RBD and suggest that Lewy body disease might provide an explanation for idiopathic RBD in the aged.

[Antimicrobial activities of piperacillin against fresh clinically isolated strains]

In order to evaluate the antimicrobial activity of piperacillin (PIPC), along with control agents, minimum inhibitory concentrations (MIC's) were determined against fresh clinically isolated strains from January to June, 1994. 1. The MIC70's of PIPC against major strains were approximately equal to those reported in the mid 1980s. 2. Strains for the study were supplied in approximately equal numbers from community-acquired hospitals and general hospitals. The ratios of bacteria resistant to beta-lactams including PIPC were low in the former group and high in the latter. 3. "New types of beta-lactam-resistant strains" which did not exist in mid 1980s but found at this time included benzylpenicillin (PCG)-insensitive Streptococcus pneumoniae, PCG-resistant S. pneumoniae, cephems-resistant Escherichia coli and beta-lactamase producing Prevotella spp. These bacteria were also found among strains obtained from community-acquired hospitals.

[Antimicrobial activities of sulbactam/ampicillin against clinically isolated microbial strains]

Antimicrobial activities were examined for sulbactam/ampicillin (SBT/ABPC) against clinically isolated microbial strains in 1987, 1990, 1994. Besides, the beta-lactamase productivity and MICs of these strains were measured, and the following conclusions were obtained. 1. The ratio of beta-lactamase producing strains were 90% of methicillin (DMPPC)-susceptible Staphylococcus aureus subsp. aureus (MSSA), about 80% of DMPPC-resistant S. aureus (MRSA), 100% of Escherichia coli, Klebsiella pneumoniae subsp. pneumoniae and Proteus mirabilis, 95% of Moraxella subgenus Branhamella catarrhalis and 15-20% of Haemophilus influenzae. Several kinds of beta-lactamase productivity were observed. 2. Antimicrobial activities of SBT/ABPC against beta-lactamase producing strains of MSSA, M. (B.) catarrhalis, H. influenzae, and almost all of Enterobacteriaceae were stronger than those of ampicillin (ABPC) and piperacillin (PIPC), but antimicrobial activities of SBT/ABPC were weak against MRSA and cephems (CEPs)-resistant strains detected in some of Enterobacteriaceae. 3. It appeared that benzylpenicillin (PCG)-insensitive Streptococcus pneumoniae (PISP) or PCG-resistant S. pneumoniae (PRSP) and CEPs-resistant Escherichia coli increased year by year. 4. Antimicrobial activities of SBT/ABPC were strong against Streptococcus pyogenes, S. pneumoniae, M. (B.) catarrhalis and H. influenzae including beta-lactamase producing strains. Additionally, beta-lactamase inhibiting effect of SBT was observed against beta-lactamase produced by S. aureus and K. pneumoniae which demonstrate indirect pathogenicity. Thus, SBT/ABPC is an injectable antibiotic that is expected to demonstrate clinical usefulness, especially as the first line drug for the respiratory tract infections that are community-acquired.

Molecular forms of human brain natriuretic peptide (BNP) in plasma of patients on hemodialysis (HD)

Plasma brain natriuretic peptide (BNP) levels have been reported to increase in patients with heart failure and end-stage renal disease (ESRD); however, little is known about molecular forms of plasma BNP that increase in these diseases. In the present study, we analyzed the molecular forms of plasma BNP in ESRD patients of both before (pre-) and after (post-) hemodialysis (HD) state. The plasma extract was analyzed by gel filtration on a TSK-GEL G2000 SW column followed by a RIA for both BNP and atrial natriuretic peptide (ANP). In the pre-HD patients, a 14- to 2300-fold increase in plasma level of immunoreactive (ir-) BNP was observed when compared to normal controls. A ratio of BNP-32 to g-BNP (pro BNP) in plasma from the patients was much larger than that in plasma from normal subjects, indicating that the high plasma level of ir-BNP level in the patients on HD largely results from a marked increase in BNP-32. HD significantly (P < 0.01) lowered the plasma levels of both BNP-32 and g-BNP with a greater reduction in BNP-32 than in g-BNP. Whereas, a-ANP was a main molecular form of plasma ANP in both pre- and post-HD plasma. These results suggest that plasma BNP-32 plays an important role in the sodium-fluid balance and that secretion and metabolism of BNP may differ from those of ANP in the HD patients.

[Beta-lactamase production of clinically isolated bacteria]

We examined beta-lactamase productions by clinically isolated strains of bacteria. The results were as follows; 1. It appears that beta-lactamases produced by strains of five species of Staphylococcus spp. are mostly penicillinase (90%). Source of beta-lactamase producing strains of Haemophilus influenzae (23%) and all of Moraxella subgenus Branhamella catarrhalis: strains (100%) are "High & Low producer" strains. 2. A large proportion of beta-lactamase producing strains of Enterobacteriaceae and Bacteroides fragilis group appeared to be "High producer" 3. beta-lactamase producing abilities are different among glucose non-fermentative Gram-negative rods. It appears that some of the strains appeared to be "High producers".

Dissociation of cardiac hypertrophy, myosin heavy chain isoform expression, and natriuretic peptide production in DOCA-salt rats

We examined the relationship between cardiac hypertrophy, myosin heavy chain (MHC) isoform expression, and production of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) before and after the development of DOCA-salt hypertension. DOCA-salt rats exhibited significant left ventricular hypertrophy at the prehypertensive stage (1 week of treatment), without MHC isoform switch or change in natriuretic peptide gene expression. In the hypertensive stage (5 weeks of treatment), pronounced left ventricular hypertrophy was observed, and this was characterized by an increase in beta-MHC protein, resulting in a switch from 90% alpha-MHC to 51% alpha-MHC and 49% beta-MHC. ANF and BNP mRNA levels and peptide content were significantly increased at this stage. Unexpectedly, the MHC isoform switch was evident in the non-hypertrophied right ventricle to the same degree as in the left ventricle. Natriuretic peptide production was also increased in the right ventricle at 5 weeks of treatment, but to a lesser degree than in the left ventricle. In contrast, in the hypertrophied left atrium there was no MHC isoform switch, while ANF and BNP mRNA levels were augmented. Plasma ANF was significantly increased in the prehypertensive stage; this was accompanied by a partial depletion of atrial ANF stores. Plasma BNP was increased only in the hypertensive stage, reflecting an increase in ventricular BNP synthesis and secretion. These results suggest that 1) cardiac hypertrophy, MHC isoform expression, and stimulation of natriuretic peptide production are processes that may be dissociated from each other; 2) increases in plasma ANF without a concomitant increase in plasma BNP reflect atrial hemodynamic overload, while increases in both ANF and BNP in plasma are associated with ventricular hypertrophy; and 3) there exist differences in the storage, secretion, and processing patterns of ANF and BNP in the atria.

[Antibacterial activities of fosfomycin against recent clinical isolates from patients of otitis media and otitis externa]

Clinical isolates from patients with otitis media and/or otitis externa were collected at otorhinology clinics nationwide and sent to us during 1989, 1991 and 1993. Minimum inhibitory concentrations (MICs) of fosfomycin (FOM) and of reference drugs against these strains were determined to investigate year-to-year antibacterial activity of FOM. A comparative analysis of the results revealed trends described below. 1. The MIC90 of FOM against Staphylococcus aureus subsp. aureus increased 4 times by 1993 as compared to those measured for strains isolated in 1984 and 1985, when FOM for otic use was under development. This was thought to be due to the recent increase in the detection frequency of methicillin-resistant S. aureus (MRSA) which is also resistant to FOM. 2. No annual changes were seen for MIC distribution of FOM against Proteus group and Pseudomonas aeruginosa. 3. Since there was no large annual change in the antibacterial activity of FOM against recent clinical isolates obtained from patients with otitis media and/or otitis externa, FOM may be considered as one of the useful drugs even now, in the mid-1990's.

[Detection of bacteria in urine using dip-slides (1). Possible occurrence of false-negative results when dip-slides are used for urine containing antibacterial agents]

Dip-slides are used as semiquantitative microbial sampling devices that are simple to use in routine testing of urine to detect the presence of bacteria, and are recommended for use in "Standard evaluation of drug efficacy in UTI". Bacterial growth on currently available dip-slides, however, may conceivably be influenced by the presence of antibacterial agents in urine. We studied clinical performance of, and effects of antibacterial agents on, such dip-slides, using two types of dip-slides, URICULTE and DIASLIDE, both of which are newly developed urine culture devices. The quantitative conventional culture method was also used as the control. 1. When single species of bacteria are present in urine specimens of patients, results obtained using URICULTE and DIASLIDE agreed very well, and they, in turn agreed well with results obtained using the quantitative, conventional culture method, also. 2. When urine specimens were spiked with Gram-negative rods and Gram-positive cocci together, URICULTE fail to provide quantitative results because colonies were not well separated and confluent growth often resulted because of a large sample volume this device employs. DIASLIDE which used a smaller amount of sample, on the other hand, provided quantitative results with adequate separation of colonies. 3. When three antibacterial agents were added to urine specimens that were spiked with bacteria, DIASLIDE produced significantly higher numbers of colonies than URICULTE. The difference probably are due to the difference in volumes of specimens used in the two devices, the former device employs approximately 1/100 as much volume of specimen as the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

[Antibacterial activities of cefetamet against clinically isolated strains from community acquired respiratory tract infections (II)]

Antibacterial activities of cefetamet (CEMT) against clinically isolated strains from patients with community acquired respiratory tract infections were compared to those of other oral beta-lactam antibiotics in the period from January to March 1994. The following results were obtained. 1. CEMT showed strong antibacterial activities against three major pathogens causing community acquired respiratory tract infections, Streptococcus pyogenes, Streptococcus pneumoniae, and Haemophilus influenzae. However, antibacterial activities of CEMT against benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP) and PCG-resistant S. pneumoniae (PRSP) were slightly weaker than of those of some the reference antibiotics. 2. No MIC value changes of CEMT were observed from year to year against Moraxella subgenus Branhamella catarrhalis and Klebsiella pneumoniae.

A novel zinc finger protein, zic, is involved in neurogenesis, especially in the cell lineage of cerebellar granule cells

To clarify the mechanism of cerebellar development, we have cloned a gene, named zic, encoding a zinc finger protein that is expressed abundantly in granule cells throughout development of the cerebellum. zic has a significant homology to the zinc finger domain of the Caenorhabditis elegans tra1 gene, the Drosophila cubitus interruptus Dominant gene, and the human GLI oncogene. An in situ hybridization study revealed that zic showed a restricted expression pattern in the granule cells and their putative precursor cells. It is also expressed at an early embryonic stage in the dorsal half of the neural tube. The expression pattern and nuclear localization were confirmed by immunohistochemical study. Furthermore, the bacterially expressed zic protein containing the zinc finger domains bound to the GLI-binding sequence. These findings suggest that zic is one of a number of nuclear factors involved in both differentiation in early development and maintenance of properties of the cerebellar granule cells.

Atrial natriuretic factor significantly contributes to the mineralocorticoid escape phenomenon. Evidence for a guanylate cyclase-mediated pathway

The mechanism underlying the mineralocorticoid escape phenomenon remains unknown. To assess the possible contribution of natriuretic peptides to mineralocorticoid escape, rats were injected with 5 mg deoxycorticosterone acetate for 3 d. Plasma atrial natriuretic factor (ANF) rose to twice basal levels and atrial ANF content decreased significantly by 24 h of treatment. This coincided with renal escape and with a significant increase in urinary cGMP excretion. Plasma ANF remained elevated and atrial ANF content continued to decline by 48 and 72 h while atrial ANF mRNA levels increased significantly only at 72 h. Plasma brain natriuretic peptide did not increase during escape although atrial brain natriuretic peptide mRNA levels increased significantly. Chronically administered HS-142-1 (HS), a specific antagonist of the guanylate cyclase-coupled natriuretic peptide receptors, significantly and dose-dependently impaired the escape phenomenon. The highest dose of HS completely suppressed the increase in urinary cGMP. Despite the continued suppression, partial escape was observed by the end of the observation period. HS alone influenced neither plasma nor tissue or urine parameters. These findings show that despite activation of atrial ANF, blockade of the guanylate cyclase-coupled natriuretic peptide receptors impairs the ability of the kidney to escape the Na+ retaining effect of excess mineralocorticoid in a dose-dependent fashion. Later-acting, unknown mechanisms eventually come into play to mediate the escape phenomenon through a guanylate cyclase-independent pathway. Therefore, ANF of cardiac origin appears to be a major factor initiating mineralocorticoid escape through a guanylate cyclase-dependent pathway.

[Antibacterial activities of new quinolones against fresh clinical isolates]

In order to investigate antibacterial activities of new quinolones (NQs) against a number of clinical isolates obtained in our laboratory during a period from February, 1993 to January, 1994, minimum inhibitory concentrations (MICs) were determined using most of the NQs available in the market as of December, 1993. The obtained results are summarized as follows: 1. Noticeable differences were observed among the antibacterial activities of 8 different NQs tested against Gram-positive bacteria, i.e., there were large differences in their MIC distributions. Some differences were also observed among different NQs in ratios of NQ-resistant strains among Staphylococcus spp. From these results, it seems necessary to further study tolerance mechanisms of these Gram-positive bacteria toward different NQs and also to examine possible differences in antibacterial activities among different NQs against Gram-positive bacteria in clinical settings. 2. MIC distributions against Gram-negative bacteria were also different among the 8 NQs tested. Though elevated MICs were observed against NQ-resistant Gram-negative bacteria in many cases, and somewhat higher, though not exceedingly high, MIC values than those against NQ-sensitive bacteria were found in other cases, patterns of MIC values against different NQ-resistant Gram-negative bacteria were similar for all of the 8 NQs tested. This may explain the fact that most of NQ-resistant Gram-negative bacteria showed similar resistant patterns to the 8 NQs tested. 3. Among the NQ-resistant bacteria, were found Haemophilus influenzae and Neisseria gonorrhoeae strains. Ratios of resistant strains were approximately 10% or lower for the former and approximately 20% for the latter. 4. With MICs of ampicillin and cefaclor used as control, it appears that benzylpenicillin (PCG)-insensitive or PCG-resistant Streptococcus pneumoniae (PISP or PRSP) and CEPs-resistant Escherichia coli are increasing.

[Antimicrobial activities of cefditoren against clinical isolates obtained from outpatients]

To examine the antimicrobial activity of cefditoren (CDTR) against strains clinically isolated from outpatients at this hospital from November, 1993 to February, 1994, the minimum inhibitory concentrations (MICs) were determined including those of the control drugs. The results were as follows: 1. CDTR showed strong antimicrobial activities against Staphylococcus aureus subsp. aureus, Streptococcus pyogenes and Streptococcus pneumoniae. The MICs of CDTR against benzylpenicillin-insensitive or -resistant S. pneumoniae distributed in the lowest concentration range even compared to those of the control drugs. 2. CDTR showed strong antimicrobial activities against Haemophilus influenzae, Moraxella subgenus Branhamella catarrhalis, Escherichia coli, and Klebsiella spp. The MIC of CDTR against CEPs-resistant E. coli was lower than those of most control drugs. 3. Since the microbes described above the major pathogens for the community-acquired infections, CDTR will be effective against infectious diseases transmitted at outpatient visits.

[Antimicrobial activities of fosfomycin against Streptococcus pneumoniae and Haemophilus influenzae recently observed in sinusitis patient]

In order to examine antimicrobial activities of fosfomycin (FOM), the minimum inhibitory concentrations (MICs) of FOM and those of control drugs were determined against Streptococcus pneumoniae and Haemophilus influenzae isolated from sinusitis patients from September to November, 1993, and the following results were obtained. 1. Among 50 S. pneumoniae strains tested, there were 10 strains (20.0%) of benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP) and 2 strains (4.0%) of PCG-resistant S. pneumoniae (PRSP); but the MIC distributions of FOM among the PISPs and the PRSPs were almost identical to those among the PCG-susceptible S. pneumoniae (PSSP). 2. There were 12 strains (24.0%) of beta-lactamase producing strains among 50 strains of H. influenzae tested, but the FOM's MIC distribution among these strains was almost identical to that among beta-lactamase non-producing strains. 3. The results obtained on the MIC90s of FOM against S. pneumoniae and H. influenzae suggest that the nebulization treatment with FOM nasal preparation satisfies the condition "above the MIC".

[Antimicrobial activities of ciprofloxacin against recently obtained clinical isolates]

In order to evaluate antimicrobial activity of ciprofloxacin (CPFX), minimum inhibitory concentrations (MICs) of CPFX and other drugs were determined against clinical isolates that were obtained in our laboratory from January to December of 1991, and of 1993. The results are summarized as follows: 1. CPFX-resistant strains were on the increase in various strains, compared to those in the early 1980s. However, many of CPFX-resistant strains were multi-drug resistant including beta-lactams. In addition, they showed cross resistance to other fluoroquinolone agents. 2. MIC distribution of other drugs suggested that there were increased frequencies of benzylpenicillin (PCG)-insensitive Streptococcus pneumoniae (PISP) and CEPs-resistant Escherichia coli. However, MIC distribution of CPFX to these resistant strains were in a relatively low range. 3. When isolates of 1991 were compared to those of 1993, we confirmed that CPFX-resistant strains decreased among certain bacteria such as Staphylococcus aureus. Also we confirmed that fewer CPFX-resistant strains were found among bacteria that may be highly related to infections encountered in daily medical care.

Plasma concentration of human brain natriuretic peptide in patients on hemodialysis

The plasma concentration of immunoreactive human brain natriuretic peptide (ir-BNP) was measured in 40 patients on hemodialysis (HD) and in 12 healthy subjects. Immunoreactive human atrial natriuretic peptide (ir-ANP) was also measured. The mean (+/- SE) plasma ir-BNP concentration in the patients before HD (18.4 +/- 3.4 fmol/mL) was markedly higher than that in the control group (0.39 +/- 0.08 fmol/mL). The plasma ir-BNP level was significantly decreased by HD from 18.4 +/- 3.4 fmol/mL to 10.5 +/- 2.2 fmol/mL (P < 0.001), but the latter value was still higher than the upper limit of the normal range for our laboratory. There were significant correlations between the plasma ir-ANP level and the mean blood pressure before HD (P < 0.05) and between the HD-induced changes in plasma ir-ANP level and mean blood pressure (P < 0.001). These correlations were not observed between the plasma ir-BNP level and mean blood pressure. The plasma ir-BNP level correlated with the cardiothoracic ratio and this correlation was closer to that between the plasma ir-ANP level and cardiothoracic ratio. Ultrasound echocardiographic studies in 13 patients revealed that the pre-HD state of high cardiac output was correlated by HD in association with decreases in plasma ir-BNP and ir-ANP levels. Correlations were observed between the pre-HD ir-ANP level and the interventricular septal thickness index (r = 0.68, P < 0.05) and between the change in ir-BNP level and that in left atrial diameter (r = 0.806, P < 0.001). In conclusion, BNP levels were high in HD patients compared with the control subjects and were decreased during HD. In addition, BNP and ANP levels correlated with several parameters of volume change and cardiac status.

[Antibacterial activities of isepamicin against fresh clinical isolates of gram-negative bacilli]

To investigate antibacterial activities of isepamicin (ISP), MICs of ISP as well as other aminoglycosides (AGs) were determined against many strains of Gram-negative bacilli that were clinically isolated in 1993. 1. No ISP-resistant strains were observed among isolates of Escherichia coli, Citrobacter diversus, Klebsiella spp., Enterobacter spp. or Proteus mirabilis. 2. ISP-resistant strains were observed among isolates of Citrobacter freundii, Serratia spp., Proteus vulgaris, Morganella morganii, Providencia spp. and Pseudomonas aeruginosa. The frequency of resistant strains in each species, however, was lower for ISP than other AGs. 3. When MIC90s were compared, antibacterial activities of ISP determined in this study were quite similar to those determined during the drug's development period (1980's) in Japan, suggesting no increase in the number of ISP-resistant strains over the years. 4. The number of clinically isolated Gram-negative bacilli resistant to multiple drugs are increasing in from year to year Japan. Our results in this study suggest that antibacterial activities of ISP may be potent enough against such Gram-negative bacilli resistant to multiple drugs.