Hepatosplenic lymphoma and visceral mast cell tumor in the liver of a dog with synchronous and multiple primary tumors

An 11-year-old spayed female American Cocker Spaniel was presented with a 4-week history of anorexia and a 1-week history of abdominal distension. Clinicopathologic and imaging abnormalities included intra-abdominal hemorrhage, granular lymphocytes (GLs) in abdominal fluid smears, a splenic mass, and hepatomegaly with diffuse multiple hypoechogenic nodules. Based on the cytologic, histologic, and immunohistochemical evaluation of the spleen and liver, the diagnosis was hepatosplenic T-cell lymphoma (HSTCL) of GLs. Postoperatively, the dog was maintained in good condition with chemotherapy (ACNU [nimustine], L-asparaginase, and prednisolone). However, on day 85, ultrasound-guided fine-needle aspiration of the liver revealed a proliferation in neoplastic mast cells not associated with the GLs. The dog was diagnosed with a visceral mast cell tumor (MCT) originating from the liver. The chemotherapy was switched to vinblastine and toceranib. The dog remained in good condition until day 141 but died due to the progression of MCT on day 158. Liver cytology on day 155 showed no GLs, although HSTCL is thought to be resistant to chemotherapy. After the definitive diagnosis of HSTCL, we monitored this patient's response to chemotherapy with blood tests, including complete blood counts, ultrasound imaging, and cytologic aspirates of liver. Although canine HSTCL has a poor prognosis, the possibility of a new neoplasm, including visceral MCT, should be considered. Periodic liver cytology might be worthwhile in dogs receiving chemotherapy for HSTCL.

A case of feline large granular lymphocyte lymphoma with complete remission and long survival by surgical resection and adjuvant nimustine administration

A 7‐year‐old spayed female Scottish Fold cat presented with a 4‐week history of anorexia, weight loss and vomiting. Abdominal ultrasonography revealed a jejunal mass and a slightly enlarged jejunal lymph node. A fine‐needle aspiration of the mass revealed many round cells with multiple small intracytoplasmic magenta granules. The mass was diagnosed as a large granular lymphocyte (LGL) lymphoma based on cytology. The LGL lymphoma was completely resected via open surgery. The histologic and cytologic evaluations showed no neoplastic findings in the jejunal lymph node, liver, spleen, kidney or bone marrow. The LGL lymphoma was localized to the jejunum. Postoperatively, the cat received chemotherapy with nimustine, l‐asparaginase and prednisolone. The cat is currently receiving nimustine every 6 weeks, without adverse events, and treatment has been administrated a total of 18 times up until day 552. The cat is in a good condition, and the LGL lymphoma has not recurred. Nimustine should be considered one of the effective chemotherapeutic agents in the treatment of feline LGL lymphoma cases in the future.

Presumptive hemophagocytic syndrome associated with immune-mediated anemia in two Miniature Dachshunds

This report describes the cases of two Miniature Dachshunds who were suspected to have immune-mediated hemolytic anemia (IMHA) and were treated with immunosuppressive therapy. However, progression of anemia, increases in C-reactive protein (CRP) and total-bilirubin (T-Bil) levels, splenomegaly, transition to nonregenerative anemia, and thrombocytopenia occurred after the treatment. Splenectomy and bone-marrow aspirations were performed subsequently. Both dogs were diagnosed with hemophagocytic syndrome (HPS) associated with IMHA. Unfortunately, they died 9 and 6 days later. These findings indicate that some cases of refractory IMHA have the pathogenicity of HPS. HPS should be included as a differential diagnosis of refractory IMHA concurrent with thrombocytopenia. Continuously elevated CRP and T-Bil levels may be helpful indicators in the detection of HPS associated with IMHA.

Precursor-targeted immune-mediated anemia in a dog with a stage IV mast cell tumor and bone marrow infiltration

A 12-year-old spayed female Shiba Inu dog was referred to our hospital for a suspected mast cell tumor (MCT) of the bone marrow (BM). Laboratory abnormalities included severe nonregenerative anemia (packed cell volume or PCV: 12.5%; reference interval (RI): 37.3-61.7%; reticulocytes: 35.1 × 10³ /µL; RI: 10-110 × 10³ /µL), and a few mast cells were visualized in the blood smear examination. The BM was hypercellular with hematopoietic cells, a decreased myeloid:erythroid (M:E) ratio (0.77; RI, 0.9-1.8), and no dysplastic hematopoietic cells. Mast cells accounted for 11.5% of the total nucleated BM cells. Neoplastic mast cells and histiocytes phagocytizing erythroid progenitor cells were occasionally noted. The dog was diagnosed with precursor-targeted immune-mediated anemia (PIMA) concurrent and a stage IV MCT infiltrating the BM. Multimodal treatment included toceranib, imatinib, vinblastine, lomustine (CCNU), prednisolone, cyclosporine, mycophenolate mofetil, and a blood transfusion. The dog died due to MCT progression lasting 139 days after the initial BM examination. To the best of our knowledge, this is the first report of a dog presenting with PIMA and a stage IV MCT infiltrating the BM.

Presumptive precursor-targeted immune-mediated anemia concurrent with gastrointestinal lymphoma in a cat

A 10-year-old spayed female mixed-breed cat presented with progressive nonregenerative anemia. Clinicopathological abnormalities included severe nonregenerative anemia (packed cell volume [PCV]: 7%, aggregate reticulocytes: 1.12 × 10³/µl) and a hypoechogenic mass well-localized in the stomach. Bone marrow (BM) smears revealed increased particle hematopoietic cellularity with decreased myeloid:erythroid (M:E) ratios, no dysplasia of any lineage, and presence of erythroid precursors phagocytized by macrophages. The cat was diagnosed with presumptive precursor-targeted immune-mediated anemia (PIMA). The stomach mass was consistent with CD 20 positive T-cell lymphoma. The lymphoma was completely resected via surgery, and the PIMA was cured by immunosuppressive therapy. On day 410, both diseases have not recurred without medications. This is the first report of feline PIMA and concurrent gastrointestinal lymphoma.

Severity of hot flushes is inversely associated with dietary intake of vitamin B6 and oily fish

Objectives: This study investigated the links between the severity of vasomotor symptoms (VMS) and the dietary consumption of a variety of nutrients. Method: A cross-sectional analysis of the first-visit records of 262 women aged 40-65 years was conducted. The severity of their hot flushes (HF) and night sweats (NS) and their dietary consumption of nutrients were evaluated using the Menopausal Health-Related Quality of Life Questionnaire and the brief-type self-administered Diet History Questionnaire, respectively. The relationships between severity of HF/NS and dietary intake were analyzed separately for 43 major nutrients. We then evaluated different food items as sources of the nutrients. Results: After adjustment for age, body mass index, menopausal status, and background factors significantly related to VMS, only vitamin B₆ (VB₆) was significantly related to severity of HF (adjusted odds ratio per 10 μg/MJ in VB₆ intake, 0.92; 95% confidence interval, 0.86-0.97). Moreover, a significant inverse relationship was found between the consumption of oily fish as a source of VB₆ and the severity of HF. Conclusions: VB₆ and oily fish intake is inversely associated with the severity of HF in middle-aged women. Therefore, increased intake of VB₆ could help attenuate HF.

A case of hemophagocytic syndrome progressing into large granular lymphoma in a dog

A 12-year-old castrated male mixed breed dog was presented with anorexia, lethargy, intermittent vomiting, diarrhea, and weight loss. Clinicopathologic and imaging abnormalities included pancytopenia, icterus, and splenomegaly with multiple minute hypoechogenic nodules. Bone marrow (BM) smears revealed 2.5% hemophagocytic macrophages. In addition, an increased number of small to intermediate lymphocytes (16.3%) and plasma cells (3.2%) were recognized in the BM smears. More than 80% of the lymphocytes contained multiple small intracytoplasmic magenta granules. Histopathologic findings of the spleen revealed hemophagocytosis. Large granular lymphocytes (LGLs) were not found on the liver cytology or splenic histopathology at this time. PCR for antigen receptor rearrangement (PARR) analysis showed a clonal reaction in the T-cell receptor ɤ (TCRɤ) gene in the BM sample. The dog was diagnosed with hemophagocytic syndrome (HPS). The dog was maintained in good condition with immunosuppressive therapy. However, the dog developed hepatic LGL lymphoma 7 months later. At this time, PARR analysis showed a clonal TCRɤ gene rearrangement in the hepatic LGL lymphoma samples. The BM and liver sample clonal rearrangements showed 100% homology, indicating that the small to intermediate granular lymphocytes in the BM at the HPS stage had progressed to hepatic LGL lymphoma. To our knowledge, this is the first report of canine secondary HPS caused by the occurrence of a BM LGL lymphoma clone that progressed to hepatic LGL lymphoma.

Clinicopathological Findings and Prognosis in Canine Cases Diagnosed As Primary Hypoplasia of the Portal Vein

Canine primary hypoplasia of the portal vein (PHPV) is a microscopic malformation of the hepatic vasculature. The prevalence, clinical signs, and clinicopathological findings of PHPV in dogs are unclear, because there are few reports concerning PHPV in the veterinary literature. This retrospective study reviewed clinical records and liver biopsy data from 48 dogs with hepatic disease that were examined at a private veterinary hospital in Japan between April 2011 and March 2014 to determine the prevalence of PHPV among dogs that underwent liver biopsy and to determine the clinical and clinicopathological findings of PHPV in dogs. Records for all 48 dogs that underwent liver biopsy were investigated. Collected data included signalment, clinical signs, physical examination findings, complete blood cell count, chemistry results, pre-and postprandial serum total bile acid concentrations, coagulation profiles (prothrombin time, activated partial thromboplastin time, fibrinogen, and antithrombin), and abdominal ultrasonography findings at the first medical examination. The diagnosis of PHPV was made on the basis of histological examination of hepatic biopsy specimens and portography or CT angiography. Among the 48 canine cases, 28 dogs (58.3%) were diagnosed with PHPV, which was the most common diagnosis. The most frequent clinical sign in dogs with PHPV was asymptomatic persistently increased liver enzymes (57.1%). Toy poodles were at a significantly higher risk of PHPV than other breeds among dogs that underwent liver biopsy (P < 0.001). The median survival time of dogs with PHPV was more than 5 years. Plasma fibrinogen concentration below the reference range was an indicator of PHPV in this study. Dogs with PHPV frequently had mild clinical signs and a favorable prognosis.

Subjective insomnia is associated with low sleep efficiency and fatigue in middle-aged women

OBJECTIVES

Many middle-aged women are affected by sleep disturbance. We investigated how subjective insomnia is associated with objective sleep parameters and other background characteristics.

METHODS

This cross-sectional study used baseline data obtained from 95 women aged 40-59 years who participated in another study assessing the effects of a dietary supplement. Participants wore an actigraph unit for 3 days to collect information concerning physical activities and objective sleep parameters and were then evaluated for body composition, cardiovascular parameters, and menopausal symptoms including insomnia and fatigue, and lifestyle factors. Stratifying Athens Insomnia Scale scores as low (0-5 points, control group) and high (≥ 6 points, subjective insomnia group), we sought to identify the parameters that are independently associated with subjective insomnia.

RESULTS

Women with subjective insomnia (n = 30) had lower sleep efficiency than did the controls. They were also older; had more live births, lower height, higher body mass index, lower ankle brachial index, and more severe menopausal symptoms including fatigue; took more naps; smoked more cigarettes; and more of them were full-time workers. Multivariate logistic regression analysis revealed that low sleep efficiency (adjusted odds ratio, 1.44 per 1% decrease in sleep efficiency; 95% confidence interval 1.06-2.05) and fatigue assessed with Brief Fatigue Inventory (BFI) (adjusted odds ratio, 1.57 per 1-point increase in BFI score; 95% confidence interval 1.19-2.13) were independent contributors to subjective insomnia.

CONCLUSIONS

Low sleep efficiency and feeling of fatigue were found to be independently associated with subjective insomnia in middle-aged women.

Intercellular adhesion molecule-1 mediates the inhibitory effects of hyaluronan on interleukin-1beta-induced matrix metalloproteinase production in rheumatoid synovial fibroblasts via down-regulation of NF-kappaB and p38

OBJECTIVE

In rheumatoid arthritis (RA), it is well known that rheumatoid synovial fibroblasts (RSF) produce matrix metalloproteinases (MMPs) when stimulated with proinflammatory cytokines such as interleukin-1beta (IL-1beta), which causes joint destruction. We have previously shown that hyaluronan (HA) inhibits IL-1beta actions in RSF via CD44, the principal HA receptor. However, CD44 mediates HA effects only partially, and intracellular events after the HA binding to its receptors remain unclear. We investigated the role of intercellular adhesion molecule-1 (ICAM-1), another cell surface receptor for HA, and the intracellular signalling pathways in the actions of HA.

METHODS

RSF were isolated from rheumatoid synovial tissues by enzymatic digestion and cultured in monolayers. The confluent cells were incubated for 48 h with IL-1beta, IL-1beta in the presence of HA, or IL-1beta in the presence of HA with pretreatment with anti-ICAM-1 antibody. Secretion of MMP-1 and MMP-3 was analysed by immunoblotting and immunofluorescence cytochemistry. Immunofluorescence cytochemistry was also performed to evaluate binding of HA to ICAM-1. The phosphorylation of nuclear factor (NF)-kappaB and mitogen-activated protein kinases (MAPKs) was analysed by immunoblotting.

RESULTS

Production of MMP-1 and MMP-3 by RSF was stimulated by IL-1beta. HA at > or =2 mg/ml significantly inhibited MMP production induced by IL-1beta in a dose-dependent manner. Moreover, pretreatment with anti-ICAM-1 antibody at 50 mug/ml significantly blocked the effects of HA on the actions of IL-1beta on RSF, as shown by immunoblotting and immunofluorescence cytochemistry. Another immunofluorescence cytochemistry study demonstrated that HA bound RSF via ICAM-1. Inhibition studies revealed the requirement of NF-kappaB, p38 and c-jun NH2-terminal kinase (JNK) for IL-1beta-induced MMP production. IL-1beta activated all three pathways, whereas HA down-regulated their phosphorylation. Pretreatment with anti-ICAM-1 antibody reversed the inhibitory effects of HA on the activation of NF-kappaB and p38 without affecting JNK.

CONCLUSION

HA suppresses IL-1beta-enhanced MMP-1 and MMP-3 synthesis in RSF via ICAM-1 through down-regulation of NF-kappaB and p38. Intra-articular injection of HA of high molecular weight may work through such a mechanism in RA joints.

COOH-terminal heparin-binding fibronectin fragment induces nitric oxide production in rheumatoid cartilage through CD44

OBJECTIVES

To examine the mechanism of nitric oxide (NO) production by a COOH-terminal heparin-binding fibronectin fragment (HBFN-f) in rheumatoid arthritis (RA) cartilage.

METHODS

Articular cartilage slices from RA knee joints and normal hip joints were cultured with HBFN-f. Secreted NO levels in conditioned media were determined. Cultures were pretreated with anti-CD44 antibody or HBFN-f-derived synthetic peptide (peptide V; WQPPRARI) to evaluate the role of CD44 in HBFN-f action. Immunofluorescence histochemistry was performed using fluorescein isothiocyanate-conjugated anti-CD44 antibody.

RESULTS

HBFN-f stimulated NO production in a dose-dependent manner. Whereas CD44 expression was up-regulated in RA cartilage, anti-CD44 antibody blocked HBFN-f-stimulated NO production. Peptide V with heparin-binding ability significantly reduced NO levels elevated by HBFN-f. Compared with normal cartilage, cartilage response to HBFN-f and the blocking effects of anti-CD44 antibody on HBFN-f action were stronger in RA cartilage.

CONCLUSIONS

The present study clearly demonstrated that HBFN-f stimulated NO production through CD44 in RA cartilage. Increased expression of CD44 in RA cartilage may play a pathological role in joint destruction through enhanced NO production by binding to fibronectin fragments such as HBFN-f.

Effect of a new hypoglycemic agent, A-4166 [(-)-N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine], on postprandial blood glucose excursion: comparison with voglibose and glibenclamide

(-)-N-(trans-4-Isopropylcyclohexanecarbonyl)-D-phenylalanine (A-4166) is a new nonsulfonylurea hypoglycemic agent that lowers blood glucose by stimulating insulin release. In the present study, we examined the effects of A-4166, voglibose (an alpha-glucosidase inhibitor), and glibenclamide (a sulfonylurea) on the postprandial glycemic increase in rats with or without diabetes mellitus. Oral administration of A-4166 (25-100 mg/kg) dose-dependently decreased blood glucose with a rapid onset and short duration in normal rats. On the other hand, glibenclamide (1-4 mg/kg) showed a slower onset of its hypoglycemic action, and voglibose (0.2 mg/kg) had no effect. In the case of postprandial glucose excursion, the carbohydrate-induced increase in blood glucose was reduced by oral administration of either A-4166 or voglibose without causing sustained hypoglycemia in both normal and neonatal streptozotocin-induced diabetic rats. However, the efficacy of voglibose varied with the type of carbohydrate load. Glibenclamide produced a prolonged decrease in blood glucose without any appreciable effect on the initial glucose excursion. After sucrose loading, plasma insulin levels during the initial 1 h were significantly higher in A-4166-treated rats than in control rats, while voglibose completely inhibited the insulin response to sucrose. In glibenclamide-treated rats, an augmented insulin response was not seen. In conclusion, unlike other hypoglycemic agents, A-4166 suppresses postprandial glucose excursions by stimulating the early phase of insulin secretion.

Hypoglycaemic and insulinotropic effects of a novel oral antidiabetic agent, (-)-N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine (A-4166)

1. (-)-N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine (A-4166), a novel oral hypoglycaemic agent is a non-sulphonylurea insulin secretagogue. 2. We investigated the insulin-releasing action and hypoglycaemic effect of A-4166 compared to sulphonylureas in vitro and in vivo. 3. A-4166 stimulated insulin secretion from rat freshly isolated pancreatic islets at concentrations from 3 x 10(-6) M to 3 x 10(-4) M in the presence of 2.8 mM glucose. There was no obvious difference in glucose dependency between the insulinotropic effect of A-4166 and that of glibenclamide, and no additive or synergistic effect was observed between these two drugs. 4. A-4166 displaced [3H]-glibenclamide bound to intact HIT-T15 cells in a concentration-dependent manner. The Ki value was 4.34 +/- 0.04 x 10(7) M, and the displacement potency of A-4166 was between that of glibenclamide and tolbutamide, being similar to that of gliclazide. 5. Inf fasted beagle dogs, A-4166 showed a dose-dependent hypoglycaemic effect after oral administration over the range 1 to 10 mg kg-1. The hypoglycaemic action of A-4166 showed an earlier onset and a shorter duration than that of sulphonylureas. 6. Simultaneous measurement of plasma insulin levels revealed that the hypoglycaemic effect of A-4166 was caused by a rapid-onset and brief burst of insulin secretion. 7. The pharmacokinetic profile of A-4166 was consistent with the changes of the blood glucose and plasma insulin levels. 8. Although the in vitro insulin-releasing effect of A-4166 was similar to that of sulphonylureas, its hypoglycaemic effect was more rapid and shorter-lasting, associated with rapid absorption and clearance. Thus, A-4166 may be useful in suppressing postprandial hyperglycaemia in patients with non-insulin-dependent diabetes mellitus.

Saccharomyces cerevisiae IRE2/HAC1 is involved in IRE1-mediated KAR2 expression

The Saccharomyces cerevisiae IRE1 gene, encoding a putative receptor-type protein kinase, is known to be required for inositol prototrophy and for the induction of a chaperon molecule, BiP, encoded by KAR2, under stress conditions such as tunicamycin addition. We have characterized a yeast gene, IRE2, which was isolated as a suppressor gene that complements the inositol auxotrophic phenotype of the ire1 mutation. Sequencing analysis revealed that IRE2 is identical to HAC1, which encodes a transcription factor having a basic-leucine zipper motif. Introduction of IRE2/HAC1 into the ire1 mutant clearly restored the expression of KAR2 upon tunicamycin treatment. ire2/hac1-disrupted yeast cells showed not only the inositol auxotrophic phenotype but also the tunicamycin sensitivity, and failed to induce the expression of KAR2. These results clearly indicate that the IRE2/HAC1 gene product plays a critical role in the induction of KAR2 expression and in the inositol prototrophy mediated by IRE1.

Somatostatin and insulin secretion due to common mechanisms by a new hypoglycemic agent, A-4166, in perfused rat pancreas

N-[(trans-4-isopropylcyclohexyl)-carbonyl]-D-phenylalanine (A-4166) is a nonsulfonylurea hypoglycemic agent that decreases blood glucose levels in nondiabetic and diabetic animals. In the present study, we attempted to determine the effect of A-4166 on hormone secretion from the in vitro-perfused rat pancreas and to examine the underlying secretory mechanisms. In the presence of basal glucose (3 mmol/L), A-4166 markedly stimulated insulin and somatostatin release in a concentration-dependent manner over 0.03 to 3 mmol/L. A sulfonylurea, tolbutamide, also stimulated insulin and somatostatin release. A-4166 and tolbutamide elevated the level of glucagon release; however, the change lacked a clear concentration-dependent property. A-4166 at 0.3 mmol/L and tolbutamide at 3 mmol/L exhibited maximal stimulation of insulin release to a similar extent, indicating that A-4166 is one log-order more potent than and as effective as tolbutamide. By contrast, A-4166 stimulated somatostatin release to a threefold greater extent than tolbutamide. A-4166 evoked an increase in the cytosolic free-Ca2+ concentration ([Ca2+]i) in rat pancreatic beta cells. [Ca2+]i and insulin secretory responses to A-4166 were inhibited by nitrendipine (NTD), a blocker of the L-type Ca2+ channel, and by diazoxide (DAZ), an opener of the adenosine triphosphate (ATP)-sensitive K+ channel. Furthermore, A-4166-stimulated somatostatin release was also inhibited by NTD and by DAZ. The results indicate that A-4166 and tolbutamide stimulate the release of insulin and somatostatin, and that A-4166 is much more effective than tolbutamide in releasing somatostatin, a hormone that attenuates hyperglycemia under certain circumstances. It is concluded that A-4166-induced insulin release is mediated by an increase in [Ca2+]i in beta cells. An inhibition of ATP-sensitive K+ channels and a consequent activation of L-type Ca2+ channels appear to play a key role not only in insulin secretion from beta cells, but also in somatostatin secretion from delta cells in response to A-4166.

A new hypoglycemic agent, A-4166, inhibits ATP-sensitive potassium channels in rat pancreatic beta-cells

Effects of a new hypoglycemic drug, N-[trans-4-isopropylcyclohexy-carbonyl]-D-phenylalanine (A-4166), on membrane current were investigated using the patch-clamp technique in single pancreatic beta-cells isolated from rats. A-4166, at a concentration of 10 microM, depolarized membrane potential of beta-cells and evoked action potentials in the presence of 2.8 mM glucose. The single ATP-sensitive K+ channel (K-ATP channel) current recorded in cell-attached membrane patches was reversibly inhibited by A-4166 (> 0.1 microM) without a change in the single-channel conductance of the K-ATP channel. Both A-4166 and tolbutamide inhibited the whole cell K-ATP channel current with half-maximum inhibition (IC50) of 0.23 and 12.8 microM, respectively (Hill coefficient = 1). In inside-out membrane patches, the IC50 with A-4166 occurred at 4.5 nM, in contrast to 0.7 microM for tolbutamide. A-4166 did not affect L- and T-type Ca2+ channels or the time-dependent outward current. We conclude that A-4166 specifically blocks the K-ATP channel and that the blockade is more potent than that of tolbutamide. The action of A-4166 underlies the mechanism by which the drug stimulates insulin secretion from beta-cells.

Possible role of the sympathetic nervous system in responses to interleukin-1

Interleukin-1 (IL-1) is a key mediator of changes in immune, endocrine and metabolic activities, collectively called the acute phase response, seen during infection and tissue injury. The purpose of the present study was to clarify a possible role of the sympathetic nervous system in the responses to IL-1 in rats. Intraperitoneal injection of IL-1 elicited an increase in rectal temperature and white blood cell count and a decrease in the plasma levels of glucose, iron and triglyceride. Pretreatment of rats with 6-hydroxydopamine or a ganglionic blocking agent abolished some of the responses, such as hypoglycemia and the increased white blood cell count. IL-1 injection also accelerated norepinephrine turnover, an index of sympathetic nerve activity, in the spleen and lung without appreciably affecting many other organs, such as the liver, heart, pancreas and brown adipose tissue. It was concluded that IL-1 activates the sympathetic nerves specifically in the spleen and lung, and can thereby influence the immune and metabolic functions of these organs.

Interleukin-1 increases norepinephrine turnover in the spleen and lung in rats

To clarify effects of interleukin-1 on sympathetic nerve activity, norepinephrine turnover in various organs was assessed in rats after intraperitoneal injection of recombinant human interleukin-1 beta. Interleukin-1 administration increased norepinephrine turnover in the spleen, lung and hypothalamus without appreciable effect in the heart, liver, submandibular gland, thymus, pancreas, brown adipose tissue and medulla oblongata. Similar changes in norepinephrine turnover were also found after the administration of bacterial endotoxin. It was concluded that interleukin-1 activates the sympathetic nerves specifically in the spleen and lung.

Ototoxic effects of a pseudodisaccharide aminoglycoside antibiotic, dactimicin, on the inner ears of guinea pigs

The effect of dactimicin on the inner ear of guinea pigs was investigated by comparing it with the effects of ribostamycin, astromicin and amikacin. At doses of 200 and 400 mg/kg/day for 4 weeks, no pinna reflex loss was observed, but 2 animals receiving 400 mg dactimicin/kg/day showed unilateral loss of the outer hair cells in the cochlea and very scattered loss of the hair cells in the vestibular organ. At doses of 400 and 500 mg dactimicin/kg/day for 5 weeks, all surviving animals showed no abnormality of the outer hair cells, the inner hair cells and the spiral ganglion cells in the cochlea except for scattered unilateral loss of the outer hair cells and loss of the stria vascularis. Based on these observations, it is concluded that the ototoxicity of dactimicin on the inner ear of guinea pigs is the same as or a little stronger than that of ribostamycin, weaker than or the same as that of astromicin and weaker than amikacin.

[Evaluation of ototoxic effect of micronomicin by intravenous drip infusion]

Ototoxic effect of micronomicin (MCR) in intravenous drip administration was investigated in guinea pigs (300--400 g) receiving MCR for 30 days at dose of 50 and 100 mg/kg, respectively. MCR was dissolved in physiologic saline and 1.5 ml of the solution was infused through polyethylene tube into the left external jugular vein with Perista mini-pump for 60 minutes every day after measurement of body weight. Auditory impairment was monitored by pinna reflex audiometry. Pinna reflex loss was not detected in any animal in frequency range (0.5 to 20 kHz). Cochlear hair cell damage generally was of mild degree. Two out of 6 animals treated with MCR 50 mg/kg (Table 1) showed outer hair cell loss confined to unilateral basal end and posterior 3/4 of the first turn, respectively. Outer hair cell loss was noticed in 4 of 9 animals receiving MCR 100 mg/kg (Table 2); much less extensive in 3 animals, unsymmetrical slightly extensive in remaining 1. Unilateral circumscribed loss of inner hair cells was noticed at lower part of the hook in the latter one. Vestibular hair cell loss was scattered and less extensive and occurred in 4 of the 6 50 mg/kg given animals and in 7 of the 9 100 mg/kg ones. Comparison in incidence and extension of the outer hair cell loss of the cochlea (Tables 3, 4) in the present study and previous ones on the ototoxic effect of MCR in intramuscular and intravenous administration suggests that there was no distinct difference in enhancement of the ototoxic effect in the intravenous drip administration.

[Effect of intravenous administration of micronomicin on the inner ear of guinea pigs]

The present experiment was made to clarify the effect of intravenous administration of micronomicin (sagamicin, MCR) on the inner ear of guinea pigs (300--350 g). MCR was given to the animals intravenously at dose of 25, 50 mg/kg and 100 mg/kg, respectively for 28 days. Pinna reflex test in frequency range from 20 kHz to 0.5 kHz was performed before, during and after the administration. The temporal bones were removed after intravital perfusion of the inner ears with neutral formation after the end of the administration. Histopathological examination was performed on the serial celloidin sections of the inner ears which had been stained with hematoxylin eosin. The following results were obtained. 1. MCR had a mild corti toxicity, which did not show remarkable dose dependent increase. 2. MCR had more affinity for the vestibular organs than for the organ of corti. The affinity for the vestibular organ increased with increase in dose. 3. MCR showed less increase in corti toxicity in intravenous administration than in intramuscular injection. However, the affinity of MCR for the vestibular organ showed little more increase in the intravenous administration than in the intramuscular injection.

[Ototoxicity study of netilmicin in pregnant guinea pigs and the embryo]

The ototoxicity of netilmicin (NTL) in pregnant guinea pigs (Hartley strain) and the newborn was examined and compared to that of gentamicin (GM). NTL was administered intramuscularly at dose of 90 mg/kg to pregnant guinea pigs from day 0 to day 35 of pregnancy (the early period of pregnancy) or from day 42 of pregnancy to 1 day prior to delivery (the late period of pregnancy). GM at dose of 45 mg/kg or physiological saline were administered intramuscularly to pregnant guinea pigs during the late period of pregnancy. Four of 5 dams given NTL during the early period of pregnancy, 4 of 7 dams given TNL during the late period of pregnancy, and 2 of 4 dams given GM during the late period of pregnancy died. No pinna reflex loss in frequency range from 2 to 20 KHz were detected in mother guinea pigs treated with NTL either during the early period of pregnancy or during the late period of pregnancy. GM caused a loss of pinna reflex at 20 KHz in mother guinea pigs treated during the late period of pregnancy. Histopathologically, no damages were detected in the cochlea of mother guinea pigs treated with NTL during the early or late period of pregnancy, whereas slight scattered loss of hair cells was seen in the vestibulum. However, GM at dose of 45 mg/kg, caused an incomplete scattered loss of outer hair cells in the spiral organ, moderate atrophy of the spiral ganglion cells and a partial loss of hair cells in the vestibular organs in mother guinea pigs treated during the late period of pregnancy. In newborn guinea pig from the pregnant one treated with NTL during the early period of pregnancy, there was no loss of pinna reflex. The same results were obtained in newborn guinea pigs from the pregnant ones treated with either NTL or GM during the late period of pregnancy. No histopathological damages were detected. The present study suggests that NTL has a minimal effect on the auditory and vestibular organs in pregnant guinea pigs and the newborn and is considered to be 1 of the aminoglycosides with low ototoxic potential.

[Animal test for evaluation of ototoxicity and safety of KW-1062 (author's transl)]

KW-1062, a new aminoglycoside antibiotic, was tested for the evaluation of audiotoxicity in administration at higher dosage and compared with the audiotoxicity of gentamicin. KW-1062 was given at dosage of 50, 100 and 150 mg/kg intramuscularly for 4 weeks to each group consisting of 10 healthy guinea pigs, respectively. Gentamicin was administered at dosage of 25, 35, 50 and 100 mg/kg in the same way as in KW-1062 to the guinea pigs. In the present study the differential frequency pinna reflex test in the frequency range from 20 kHz to 0.5 kHz was performed before and during administration of the drugs, to evaluate the audiotoxicity. Comparison of number of animal with pinna reflex loss and extent of frequency range of pinna reflex loss revealed that KW-1062 at dose of 150 mg/kg is less audiotoxic than gentamicin at 50 mg/kg and 100 mg/kg, and approximately equivalent in audiotoxicity to gentamicin at dose of 35 mg/kg.

Audiotoxicosis in newborn guinea pigs from pregnant ones given sisomicin

The audiotoxic effect of sisomicin was investigated in guinea pig injected intramuscularly with 6.25, 12.5, 25 and 50 mg/kg of sisomicin sulfate (potential) during weeks 1--5 or 5--9 of pregnancy, and the transplacental effect on their offspring was studied. While, in some dams the higher doses of sisomicin produced a limited effect on the pinna reflex and the outer hair cells of the organ of Corti, no such effects were noted in any of the offspring during the 3-week postnatal observation period.

[Ototoxic effect of BB-K8 administered to pregnant guinea pigs on development of inner ear of intrauterine litters (author's transl)]

Transplacental ototoxic effects of BB-K8 on development of inner ear in intrauterine guinea pigs were evaluated by differential frequency pinna reflex test in range of 20 kHZ to 500 HZ and histopathological examination of spiral and vestibular organs in new born guinea pigs from pregnant ones given BB-K8 i.m. during gestation.

MATERIALS AND METHODS

Twenty-five pregnant guinea pigs of the Hartley strain and 63 new-born guinea pigs from the pregnant ones were used in the study. Following antibiotics were given i.m. daily to the 20 pregnant guinea pigs from 7th day of gestation for 56 days. BB-K8 was given at the dose level of 100 mg/kg and 200 mg/kg, respectively. Kanamycin (KM) was administered at the dose level of 100 mg/kg and 200 mg/kg, respectively. Physiological saline solution (1.0 ml/kg) was given i.m. to the pregnant guinea pigs for 56 days. The differential frequency pinna reflex test was performed in the frequency range from 20 kHZ to 500 HZ to determine an extent of frequency of pinna reflex loss. The test was carried out before the start of administration of the antibiotics and once a week during the administration. After the last injection of the antibiotics, intravital perfusion fixation was carried out in the new born animals under anesthesia with nembutal. Histopathological examination was made in celloidin serial sections of the cochlea and vestibulum of the new born animals to observe an extent or degree of hair cell damage.

RESULTS

(1) The differential frequency pinna reflex test revealed that new born guinea pigs from the pregnant ones given BB-K8 and KM respectively at the dose level of 100 mg/kg did not show occurrence of pinna reflex loss at any frequency tested. At the dose level of 200 mg/kg, BB-K8 did not result in transplacental hearing impairment in new born guinea pigs, but KM caused transplacental pinna reflex loss in the highest frequencies from 20 k to 15 kHZ in 3 of 10 animals. (2) Histopathological examination detected that unilateral incomplete loss of outer hair cells of the spiral organ confined to the basal end of cochlea was found in 3 of 13 new born guinea pigs from the pregnant ones treated with BB-K8 (100 mg/kg). In the animals, slight damage of hair cells in the vestibular organs occurred in 100%. These hair cell damages were enhanced slightly in the new born guinea pigs from the pregnant ones treated with BB-K8 (200 mg/kg) and much more in the new born ones from the pregnant ones treated with KM (100 mg/kg, 200 mg/kg). (3) These results suggest that BB-K8 has a mild potency to cause transplacental ototoxic damage in the inner ear of intrauterine guinea pigs within the pregnant ones treated for 56 days (normal gestation period approximately 70 days).

[Ototoxicity of spectinomycin (author's transl)]

Spectinomycin is an aminocyclitol antibiotic, but different in chemical structure from other aminocyclitol antibiotics such as streptomycin, kanamycin and gentamicin. Spectinomycin clinically has been proven to be highly effective in the intramuscular single-dose treatment of gonorrhea. According to NOVAK et al. (1974), all evidence from pharmacological and clinical efficacy studies to date indicates that spectinomycin is free from ototoxic effects at the dose levels recommended for single-dose treatment of gonorrhea (2 or 4 g) or repeated i.m. or i.v. doses, 8g/day. The present experimental study has been made to evaluate the ontoxocic effects of spectinomycin in Hartley strain guinea pigs given i.m. a single-high dose (800 mg/kg or 1,600 mg/kg) and repeated-slightly higher dose (80 mg/kg or 160 mg/kg daily for 4 weeks) respectively. Differential frequency pinna reflex test in frequency range from 20 KHz to 500 Hz revealed that no animals showed disappearance of pinna reflex in the frequencies tested. Histologic examination in serial celloidin sections of the cochlea and vestibulum disclosed that a few animals given a single-high dose of spectinomycin (800 mg/kg or 1,600 mg/kg) and repeated-slightly higher dose or spectinomycin (80 mg/kg daily for 4 weeks) respectively showed limited mild damage of outer hair cells in the spiral organ and of hair cells in the vestibular organ. There were histologically a few focal necrosis in the liver and scattered interstitial cell infiltration around the proximal convoluted tubules which are lined with regenerated epithelial cells in some animals given the single-high dose (800 mg/kg or 1,600 mg/kg) or repeated-slightly higher dose (80 mg/kg or 160 mg/kg daily for 4 weeks) of spectinomycin. Positive correlation between the extent of the hair cell damage and the injury of the liver and kidney was not confirmed. The present study suggests that administration of spectinomycin at the dose levels recommended for single-dose treatment of gonorrhea (2 or 4 g) most probably is free from ototoxic effect.