Additional studies on nicotine exposure in horses: Accurate quantification and elimination profiles of potential biomarkers in plasma and urine

RATIONALE

For the purpose of doping control, this is the first report of accurate quantification of four critical structural isomers of nicotine metabolites (trans-3'-hydroxycotinine, cis-3'-hydroxycotinine, 5'-hydroxycotinine, and N'-hydroxymethylnorcotinine) in equine plasma and urine for the establishment of their elimination profiles. Besides, the pharmacokinetic studies of trans-3'-hydroxycotinine and N'-hydroxymethylnorcotinine in equine plasma and urine are also presented for the first time.

METHODS

The accurate quantification methods of the aforementioned four structural isomers in horse plasma and urine were successfully developed and validated using the solid-phase extractions followed by liquid chromatography/tandem mass spectrometry analysis. Baseline chromatographic separation was achieved to completely differentiate these isomers, which shared the same selected reaction monitoring transition. Such methods were applied to post-administration samples obtained from the nicotine and tobacco leaf administration studies for the establishment of pharmacokinetic profiles.

RESULTS

N'-Hydroxymethylnorcotinine could be quantified for the longest period, ranging from 48 to 72 h in plasma and 96 h in urine after a single administration of 250 mg of nicotine and an equivalent amount of nicotine in tobacco leaves. In terms of detection, both N'-hydroxymethylnorcotinine and trans-3'-hydroxycotinine could be detected up to the last sample collection time point (96 h), indicating that they are the most appropriate biomarkers for nicotine exposure.

CONCLUSIONS

N'-Hydroxymethylnorcotinine and trans-3'-hydroxycotinine were detected longest in plasma and urine samples after both nicotine and tobacco leaf administrations, and N'-hydroxymethylnorcotinine was deemed most appropriate as a monitoring target due to its relatively higher abundance and slower elimination rate. These two biomarkers could also be used to differentiate sample contamination by tobacco products and genuine nicotine exposure to horse regardless of intentionality.

Identification of potential biomarkers in urine and plasma after consumption of tobacco product in horses

The use of nicotine stimulants in horses is generally banned in horse racing and equestrian sports-accidental consumption of tobacco products is one of the possible causes of nicotine exposure in horses. The authors recently reported a comprehensive metabolic study of nicotine in equines, differentiating between nicotine exposure and sample contamination by means of a nicotine biomarker trans-3'-hydroxycotinine. To identify potential biomarkers for the differentiation of genuine nicotine administration and consumption of tobacco products, tobacco leaves (equivalent to 250 mg of nicotine) were nasoesophageally administered to three thoroughbred mares. Quantification methods of anatabine in plasma and urine were newly developed and validated and successfully applied to post-administration samples. Previously reported simultaneous quantification methods of eight target analytes including nicotine and its metabolites in plasma and urine were also applied to the samples. The results demonstrate that both trans-3'-hydroxycotinine and anatabine could be used as potential biomarkers in equine urine and plasma to indicate recent exposure to tobacco products in horses. As well, trans-3'-hydroxycotinine had the longest half-life as a detectable metabolite in urine and plasma. To our knowledge, this is the first report of a comprehensive study of tobacco product detection in horses.

Comprehensive metabolic study of nicotine in equine plasma and urine using liquid chromatography/high-resolution mass spectrometry for the identification of unique biomarkers for doping control

Nicotine is classified as a stimulant, and its use is banned in horse racing and equestrian sports by the International Federation of Horseracing Authorities and the Fédération Équestre Internationale, respectively. Because nicotine is a major alkaloid of tobacco leaves, there is a potential risk that doping control samples may be contaminated by tobacco cigarettes or smoke during sample collection. In order to differentiate the genuine doping and sample contamination with tobacco leaves, it is necessary to monitor unique metabolites as biomarkers for nicotine administration and intake. However, little is known about the metabolic fate of nicotine in horses. This is the first report of comprehensive metabolism study of nicotine in horses. Using liquid chromatography/electrospray ionization high-resolution mass spectrometry, we identified a total of 17 metabolites, including one novel horse-specific metabolite (i.e., 4-hydroxy-4-(3-pyridyl)-N-methylbutanamide), in post-administration urine samples after nasoesophageal administration of nicotine to three thoroughbred mares; eight of these compounds were confirmed based on reference standards. Among these metabolites, N-hydroxymethylnorcotinine was the major urinary metabolite in equine, but it could only be tentatively identified by mass spectral interpretation due to the lack of reference material. In addition, we developed simultaneous quantification methods for the eight target analytes in plasma and urine, and applied them to post-administration samples to establish elimination profiles of nicotine and its metabolites. The quantification results revealed that trans-3'-hydroxycotinine could be quantified for the longest period in both plasma (72 h post-administration) and urine (96 h post-administration). Therefore, this metabolite is the most appropriate monitoring target for nicotine exposure for the purpose of doping control due to its long detection times and the availability of its reference material. Further, we identified trans-3'-hydroxycotinine as a unique biomarker allowing differentiation between nicotine administration and sample contamination with tobacco leaves.

Detection and longitudinal distribution of GW1516 and its metabolites in equine hair for doping control using liquid chromatography/high-resolution mass spectrometry

RATIONALE

GW1516 is a peroxisome proliferator-activated receptor-δ (PPAR-δ) agonist that is banned in horseracing and equestrian sports. Long-term detection and longitudinal distribution of GW1516 in the mane of a horse are reported for the first time and this hair analysis could prolong the detection window of GW1516 for doping control.

METHODS

Mane hairs were divided into three segments (0-7, 7-15, and >15 cm from the cut end) and completely pulverized and homogenized for analysis. The pulverized hair samples were extracted with methanol followed by further purification and the extracts were analyzed by liquid chromatography/electrospray ionization high-resolution mass spectrometry (LC/ESI-HRMS) using a Q-Exactive instrument. This method was successfully validated and applied to post-administration samples to confirm the presence of GW1516 and its metabolites and estimate the uptake amounts of GW1516.

RESULTS

After administration of 150 mg of GW1516 to a thoroughbred mare, GW1516 was detected in one of two segments of all mane hairs, and four metabolites, namely GW1516 sulfoxide, GW1516 sulfone, 5-(hydroxymethyl)-4-methyl-2-(4-trifluoromethylphenyl)thiazole (HMTT), and 4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazole-5-carboxylic acid (MTTC), were also identified. The longitudinal distribution analysis results showed that the maximum uptake of GW1516 into hair (approximately 0.05 pg/mg) was observed at around 13 weeks post-administration and GW1516 could be detected and confirmed up to 6 months post-administration.

CONCLUSIONS

The parent drug GW1516 was identified as the most appropriate monitoring target in equine hair for controlling its misuse in horses. The use of hair analysis could extend the detection time of GW1516 to at least 6 months after the administration of 150 mg of GW1516 to a thoroughbred mare.

Metabolic study of GW1516 in equine urine using liquid chromatography/electrospray ionization Q-Exactive high-resolution mass spectrometry for doping control

RATIONALE

The use of GW1516, a peroxisome proliferator-activated receptor δ (PPAR δ) agonist, is strictly prohibited in both horseracing and equestrian competitions. However, little is known about its metabolic fate in horses. To the best of our knowledge, this is the first reported metabolic study of GW1516 in equine urine.

METHODS

Urine samples obtained from a thoroughbred after nasoesophageal administration with GW1516 were protein-precipitated and the supernatants were subsequently analyzed by liquid chromatography/electrospray ionization high-resolution mass spectrometry (LC/ESI-HRMS) with a Q-Exactive mass spectrometer. Monoisotopic ions of GW1516 and its metabolites were monitored from the full-scan mass spectral data of pre- and post-administration samples. A quantification method was developed and validated to establish the excretion profiles of GW1516, its sulfoxide, and its sulfone in equine urine.

RESULTS

GW1516 and its nine metabolites [including GW1516 sulfoxide, GW1516 sulfone, 5-(hydroxymethyl)-4-methyl-2-(4-trifluoromethylphenyl)thiazole (HMTT), methyl 4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazole-5-carboxylate (MMTC), 4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazole-5-carboxylic acid (MTTC), and M1 to M4] were detected in post-administration urine samples. GW1516 sulfoxide and GW1516 sulfone showed the longest detection times in post-administration urine samples and were therefore recommended as potential screening targets for doping control purposes. Quantitative analysis was also conducted to establish the excretion profiles of GW1516 sulfoxide and GW1516 sulfone in urine.

CONCLUSIONS

For the purposes of doping control of GW1516, the GW1516 sulfoxide and GW1516 sulfone metabolites are recommended as the target analytes to be monitored in equine urine due to their high specificities, long detection times (1 and 4 weeks, respectively), and the ready availability of their reference materials.

Doping control analysis of GW1516 in equine plasma using liquid chromatography/electrospray ionization Q-Exactive high-resolution mass spectrometry

RATIONALE

GW1516 is a peroxisome proliferator-activated receptor-δ agonist in the class of hormones and metabolic modulators. The use of GW1516 is banned in both horseracing and equestrian competitions. To the best of our knowledge, this is the first metabolic study of GW1516 in horses.

METHODS

After protein precipitation of pre- and post-administration plasma GW1516 samples, the supernatants were analyzed using liquid chromatography/electrospray ionization Q-Exactive high-resolution mass spectrometry to detect GW1516 and its metabolites. Monoisotopic ions of GW1516 and its metabolites were monitored from the full-scan mass spectral data of pre- and post-administration samples. Quantification methods were developed and validated to establish the elimination profiles of GW1516, its sulfoxide, and its sulfone in equine plasma.

RESULTS

GW1516 and its four metabolites GW1516 sulfoxide, GW1516 sulfone, 5-(hydroxymethyl)-4-methyl-2-(4-trifluoromethylphenyl)thiazole (HMTT), and M1 were detected in post-administration plasma samples. GW1516 sulfoxide, GW1516 sulfone, and HMTT were identified by comparison with their respective reference standards whereas M1 was tentatively identified as 4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazole-5-carboxylic acid by mass spectral interpretation. GW1516 had the longest detection time in post-administration plasma. The elimination profiles of GW1516, its sulfoxide, and its sulfone in plasma were established.

CONCLUSIONS

For the purpose of doping control, GW1516 is recommended as the target analyte to be monitored in equine plasma due to its long detection time (around 1 week) and the ready availability of its reference material.

Clinical pharmacokinetics and pharmacodynamics of intravenous alfaxalone in young Thoroughbred horses premedicated with medetomidine and midazolam

To investigate the clinical pharmacokinetics and pharmacodynamics of intravenous alfaxalone in young Thoroughbred horses, seven Thoroughbred horses were randomly anaesthetised twice with either 1 or 2 mg/kg of intravenous alfaxalone after premedication with medetomidine (6 µg/kg intravenous) and midazolam (20 µg/kg intravenous). Blood samples were collected at predetermined time points up to two hours after administration. Plasma alfaxalone concentrations were quantified by a liquid chromatography tandem-mass spectrometry method and analysed by non-compartmental pharmacokinetic analysis. Induction and recovery qualities were good to excellent for both doses. Recovery time for the 2 mg/kg (median 90 minutes) was significantly longer than that for the 1 mg/kg (median 50 minutes). Respiratory rate for the 2 mg/kg was significantly lower than that for the 1 mg/kg, resulting in hypoxaemia. The median (range) elimination half-life, total clearance and volume of distribution were 58.2 (42.3-70.7) minutes, 11.6 (10.3-14.5) ml/minute/kg and 0.8 (0.7-0.9) l/kg for the 1 mg/kg and 59.8 (47.5-68.0) minutes, 14.7 (12.1-16.0) ml/minute/kg and 0.9 (0.9-1.2) l/kg for the 2 mg/kg, respectively. Alfaxalone is rapidly eliminated from the plasma in young Thoroughbred horses. Respiratory depression should be especially noted when alfaxalone is used in clinical practice.

A candidate-SNP retrospective cohort study for fracture risk in Japanese Thoroughbred racehorses

Fractures are medical conditions that compromise the athletic potential of horses and/or the safety of jockeys. Therefore, the reduction of fracture risk is an important horse and human welfare issue. The present study used molecular genetic approaches to determine the effect of genetic risk for fracture at four candidate SNPs spanning the myostatin (MSTN) gene on horse chromosome 18. Among the 3706 Japanese Thoroughbred racehorses, 1089 (29.4%) had experienced fractures in their athletic life, indicating the common occurrence of this injury in Thoroughbreds. In the case/control association study, fractures of the carpus (carpal bones and distal radius) were statistically associated with g.65809482T/C (P = 1.17 x 10^-8 ), g.65868604G/T (P = 2.66 x 10^-9 ), and g.66493737C/T (P = 6.41 x 10^-8 ). In the retrospective cohort study using 1710 racehorses born in 2000, the relative risk (RR) was highest for male horses at g.65868604G/T, based on the dominant allele risk model (RR = 2.251, 95% confidence interval 1.407-3.604, P = 0.00041), and for female horses at g.65868604G/T, based on the recessive allele risk model (RR = 2.313, 95% confidence interval 1.380-3.877, P = 0.00163). Considering the association of these SNPs with racing performance traits such as speed, these genotypes may affect the occurrence of carpus fractures in Japanese Thoroughbred racehorses as a consequence of the non-genetic influence of the genotype on the distance and/or intensity of racing and training. The genetic information presented here may contribute to the development of strategic training programs and racing plans for racehorses that improve their health and welfare.

Clinical evaluation of constant rate infusion of alfaxalone-medetomidine combined with sevoflurane anesthesia in Thoroughbred racehorses undergoing arthroscopic surgery

Background

Alfaxalone has a number of pharmacological properties which are desirable for constant rate infusion (CRI). Previously, the co-administration of alfaxalone and medetomidine is shown to be suitable for short-term anesthesia in horses. However, the use of alfaxalone–medetomidine CRI with inhalational anesthesia under surgical procedures have not been investigated in clinical cases. The aim of the present study was to evaluate the clinical efficacy of alfaxalone–medetomidine CRI in sevoflurane-anesthetized Thoroughbred racehorses undergoing arthroscopic surgery. Sevoflurane requirement, cardiovascular function, and induction/recovery quality were compared between horses maintained with sevoflurane in combination with medetomidine CRI (3 µg/kg/h) (Group M; n = 25) and those maintained with sevoflurane in combination with alfaxalone–medetomidine CRI (0.5 mg/kg/h and 3 µg/kg/h, respectively) (Group AM; n = 25).

Results

The mean end-tidal sevoflurane concentrations were significantly lower in Group AM (1.8 ± 0.2%) than in Group M (2.4 ± 0.1%). The mean dobutamine infusion rate required for maintaining mean arterial blood pressure within the target values (60–80 mmHg) was significantly lower in Group AM (0.53 ± 0.20 µg/kg/min) than in Group M (0.85 ± 0.32 µg/kg/min). Induction and recovery scores were not significantly different between two groups. However, excitatory response during recovery were observed in five horses in Group AM. The mean plasma alfaxalone concentrations were stable throughout the maintenance period (0.77 ± 0.12 to 0.85 ± 0.13 µg/mL), and decreased significantly immediately after standing (0.32 ± 0.07 µg/mL).

Conclusions

Alfaxalone–medetomidine CRI reduced sevoflurane requirement by approximately 26% with good maintenance of cardiopulmonary function in Thoroughbred racehorses undergoing arthroscopic surgery. Sevoflurane in combination with alfaxalone–medetomidine CRI may be a clinically effective anesthetic technique for Thoroughbred racehorses. However, 20% of horses administered alfaxalone showed remarkable excitatory response during recovery. Greater attention to excitatory response may be advisable if alfaxalone is used for induction or maintenance of anesthesia. A larger study is needed to explore the clinical relevance of these findings.

Evaluation of total intravenous anesthesia with propofol-guaifenesin-medetomidine and alfaxalone-guaifenesin-medetomidine in Thoroughbred horses undergoing castration

Anesthetic and cardiorespiratory effects of total intravenous anesthesia (TIVA) technique using propofol-guaifenesin-medetomidine (PGM) and alfaxalone-guaifenesin-medetomidine (AGM) were preliminarily evaluated in Thoroughbred horses undergoing castration. Twelve male Thoroughbred horses were assigned randomly into two groups. After premedication with intravenous (IV) administrations of medetomidine (5.0 µg/kg) and butorphanol (0.02 mg/kg), anesthesia was induced with guaifenesin (10 mg/kg IV), followed by either propofol (2.0 mg/kg IV) (group PGM: n=6) or alfaxalone (1.0 mg/kg IV) (group AGM: n=6). Surgical anesthesia was maintained for 60 min at a constant infusion of either propofol (3.0 mg/kg/hr) (group PGM) or alfaxalone (1.5 mg/kg/hr) (group AGM), in combination with guaifenesin (80 mg/kg/hr) and medetomidine (3.0 µg/kg/hr). Responses to surgical stimuli, cardiorespiratory values, and induction and recovery characteristics were recorded throughout anesthesia. During anesthesia induction, one horse paddled in group PGM. All horses from group AGM were maintained at adequate anesthetic depth for castration. In group PGM, 3 horses showed increased cremaster muscle tension and one showed slight movement requiring additional IV propofol to maintain surgical anesthesia. No horse exhibited apnea, although arterial oxygen tension decreased in group AGM to less than 60 mmHg. Recovery quality was good to excellent in both groups. In conclusion, TIVA using PGM and AGM infusion was available for 60 min anesthesia in Thoroughbred horses. TIVA techniques using PGM and AGM infusion provided clinically acceptable general anesthesia with mild cardiorespiratory depression. However, inspired air should be supplemented with oxygen to prevent hypoxemia during anesthesia.

Habitual intake of fermented milk products containing Lactobacillus casei strain Shirota and a reduced risk of hypertension in older people

This study investigated relationships between the frequent intake of fermented milk products containing Lactobacillus casei strain Shirota (LcS) and the onset of hypertension (resting systemic pressure ≥140 mmHg [systolic]/≥90 mmHg [diastolic], a doctor’s diagnosis and/or antihypertensive medicine use) during a 5-year period in 352 communityliving Japanese aged 65 to 93 years (125 men and 227 women). Initially normotensive subjects were divided into two groups (n=254 and n=98) on the basis of their intake of fermented milk products (<3 or ≥3 times/week, respectively), as estimated during an interview by a certified nutritionist. The incidence of hypertension over the 5-year interval was significantly lower in those who took fermented milk products ≥3 rather than <3 times/week (6.1 vs 14.2%, P=0.037). A multivariate-adjusted proportional hazards model predicted that blood pressures were significantly more likely to remain normal over 5 years in subjects who took ≥3 fermented milk products rather than <3 times/ week (relative risk 0.398 [95% confidence interval 0.167-0.948], P=0.037). These results suggest that after adjustment for potential confounders, the risk of developing hypertension is substantially lower in elderly people who take fermented milk products containing LcS at least 3 times a week.

Fermented milk containing Lactobacillus casei strain Shirota prevents the onset of physical symptoms in medical students under academic examination stress

This pilot study investigated the effects of the probiotic Lactobacillus casei strain Shirota (LcS) on psychological, physiological, and physical stress responses in medical students undertaking an authorised nationwide examination for promotion. In a double-blind, placebo-controlled trial, 24 and 23 healthy medical students consumed a fermented milk containing LcS and a placebo milk, respectively, once a day for 8 weeks until the day before the examination. Psychophysical state, salivary cortisol, faecal serotonin, and plasma L-tryptophan were analysed on 5 different sampling days (8 weeks before, 2 weeks before, 1 day before, immediately after, and 2 weeks after the examination). Physical symptoms were also recorded in a diary by subjects during the intervention period for 8 weeks. In association with a significant elevation of anxiety at 1 day before the examination, salivary cortisol and plasma L-tryptophan levels were significantly increased in only the placebo group (P<0.05). Two weeks after the examination, the LcS group had significantly higher faecal serotonin levels (P<0.05) than the placebo group. Moreover, the rate of subjects experiencing common abdominal and cold symptoms and total number of days experiencing these physical symptoms per subject were significantly lower in the LcS group than in the placebo group during the pre-examination period at 5-6 weeks (each P<0.05) and 7-8 weeks (each P<0.01) during the intervention period. Our results suggest that the daily consumption of fermented milk containing LcS may exert beneficial effects preventing the onset of physical symptoms in healthy subjects exposed to stressful situations.

Comparison of alfaxalone, ketamine and thiopental for anaesthetic induction and recovery in Thoroughbred horses premedicated with medetomidine and midazolam

REASONS FOR PERFORMING STUDY

There is limited information on clinical use of the new injectable anaesthetic agent alfaxalone in Thoroughbred horses.

OBJECTIVES

To compare anaesthetic induction and recovery characteristics and cardiopulmonary responses between alfaxalone, ketamine and thiopental in Thoroughbred horses premedicated with medetomidine and midazolam.

STUDY DESIGN

Randomised blinded experimental cross-over study.

METHODS

Six Thoroughbred horses were anaesthetised 3 times with alfaxalone 1 mg/kg bwt, ketamine 2.5 mg/kg bwt or thiopental 4 mg/kg bwt after premedication with medetomidine 6 μg/kg bwt and midazolam 20 μg/kg bwt. Qualities of anaesthetic induction and recovery were scored on a scale of 1 (poor) to 5 (excellent). Induction time and recovery time were recorded. Cardiopulmonary values (heart rate, respiratory rate, arterial blood pressures, and arterial blood gases) were recorded throughout anaesthesia. Data were analysed with nonparametric methods.

RESULTS

The anaesthetic induction (P = 0.2) and recovery (P = 0.1) quality scores (median, range) were not different amongst protocols and were 4.0, 3-5; 5.0, 4-5; 4.5, 3-5; and 4.5, 3-5; 3.5, 2-5; 4.0, 2-5 for alfaxalone, ketamine and thiopental, respectively. Induction time for ketamine (67, 53-89 s) was significantly longer than that for alfaxalone (49, 40-51 s, P = 0.01) and thiopental (48, 43-50 s, P = 0.01). Time to standing for alfaxalone (44, 40-63 min, P = 0.01) and thiopental (39, 30-58 min, P = 0.01) was significantly longer than that for ketamine (25, 18-26 min). Cardiovascular values were maintained within the clinically acceptable level throughout anaesthesia. Respiratory rate significantly decreased during anaesthesia for all 3 drugs; however, spontaneous breathing did not disappear, and PaCO₂ values were maintained at approximately 50 mmHg.

CONCLUSIONS

All 3 drugs showed similar effects in relation to anaesthetic induction and recovery qualities and cardiopulmonary responses. However, alfaxalone and thiopental prolonged recovery time compared with ketamine.

Multilocus sequence typing of bifidobacterial strains from infant’s faeces and human milk: are bifidobacteria being sustainably shared during breastfeeding?

Bifidobacteria are considered to be one of the most important beneficial intestinal bacteria for infants, contributing to the priming of the mucosal immune system. These microbes can also be detected in mother’s milk, suggesting a potential role of human milk in the colonisation of infant’s gut. However, little is known about the timing of bacteria appearance in human milk, and whether human milk is the first source of inoculation. Here, we investigated whether specific strains are shared sustainably between maternal milk and infant’s gut. Faecal samples and human milk were collected from 102 healthy mother-infant pairs (infant’s faeces: meconium, 7, 30 days of age; mother’s milk: once before delivery, colostrum, 7, 30 days after delivery). Bifidobacterial strains were isolated from these samples, and were discriminated by means of multilocus sequencing typing. No bifidobacteria were detected from human milk collected before delivery, or colostrum. Strains were isolated only from human milk samples obtained 7 days after birth or later. On the other hand, bifidobacterial strains were obtained from infant’s faeces throughout the study period, sometimes as early as the first day of life (meconium). We have found that bifidobacterial species belonging to Bifidobacterium bifidum, Bifidobacterium breve, and Bifidobacterium longum subsp. longum could be identified as monophyletic between infant’s faeces and their mother’s milk. These strains were confirmed to be sustainably shared between maternal milk and infant’s gut. Moreover, monophyletic strains were isolated at the same time point or earlier from infant’s faeces than from human milk, and none were isolated earlier from human milk than from infant’s faeces. Although it remains unclear whether human milk is the first source of microbes for infants, our results confirm that human milk is a reservoir of bifidobacteria, and specific strains are shared between infant’s intestine and human milk during breastfeeding.

Extranodal lymphoblastic lymphoma of suspected B-cell lineage in the gingiva of a racehorse, accompanied by mandibular osteolysis

A mass developed in the mandibular gingiva of a thoroughbred racehorse. When the horse could no longer eat unassisted, it was killed and immediately autopsied. Macroscopically, the mandible exhibited extensive osteolysis, with only a small amount of bone remaining around the tooth roots. The cut surface of the mass around the mandible consisted of neoplastic medullary tissue, in which osteogenesis was observed. The medullary tissue was composed of pleomorphic medium-sized to large cells, interlaced by collagen bundles. These cells had large, pale, round or ovoid, sometimes cleaved nuclei, with one or two prominent nucleoli. Mitoses were numerous. Electron microscopy showed that the cells in the medullary tissues were similar in shape to undifferentiated lymphocytes. Immunohistochemically, these cells were positive for B-cell associated antigen in the pre-B-cell stage. Our findings suggest that the horse had extranodal lymphoblastic lymphoma of suspected B-cell lineage, possibly originating from the lymphatic system of the gingiva. We consider that the osteolysis resulted from activation of osteoclasts by proliferation of the tumour cells.

Antitumor effects of the intravesical instillation of heat killed cells of the Lactobacillus casei strain Shirota on the murine orthotopic bladder tumor MBT-2

PURPOSE

To characterize the potential of heat killed Lactobacillus casei, Shirota strain (LC9018), as an alternative to bacillus Calmette-Guerin (BCG) for treating patients with bladder cancer we investigated the antitumor effects of intravesical instillation of LC9018 in the MBT-2 orthotopic bladder tumor implantation model in C3H/He mice.

MATERIALS AND METHODS

LC9018 or BCG, Tokyo 172 strain, was instilled once daily for 10 days starting on the day after orthotopic implantation of MBT-2. Tumor appearance and mean bladder weight on day 21 after tumor implantation were evaluated. Moreover, we investigated the augmentation of local cellular immunity in bladder mucosa by immunohistochemical staining and reverse transcription polymerase chain reaction.

RESULTS

Intravesical LC9018 instillation significantly reduced the rate of tumor appearance in 8 of 38 subjects (p <0.001) and mean tumor growth plus or minus standard deviation with a bladder weight of 37 +/- 49 mg. (p <0.001) compared with tumor appearance in 41 of 58 subjects and mean bladder weight 146 +/- 183 mg. in controls. BCG had no significant antitumor activity in the orthotopic implantation model. Intravesical instillation of LC9018 augmented the local expression of antitumor cytokine messenger RNA (interferon-gamma and tumor necrosis factor-alpha) and induced the infiltration of neutrophils surrounded by macrophages that phagocytosed LC9018 cells at the bladder mucosa.

CONCLUSIONS

These results suggest that LC9018 is potentially more potent and safer as a therapeutic agent than BCG for superficial bladder tumors. Furthermore, the antitumor effect of LC9018 is exerted via the augmentation of local cell mediated antitumor immunity.

Lactobacillus casei acquires the binding activity to fibronectin by the expression of the fibronectin binding domain of Streptococcus pyogenes on the cell surface

Fibronectin binding domain was expressed on the cell surface of Lactobacillus casei strain Shirota which hardly adheres to fibronectin. DNA for the fibronectin binding domain of the sfbl gene, which encodes a fibronectin binding protein of Streptococcus pyogenes ATCC 21059, was amplified with polymerase chain reaction, cloned into a surface display vector pSAK332, and introduced into L. casei. The fibronectin binding domain was expressed as a fusion protein consisting of staphylokinase of Staphylococcus aureus and the anchor sequence of cell wall-associated 763 proteinase of Lactococcus lactis NCDO 763. The fibronectin binding ability of the resulting L. casei was confirmed with Western blot analysis, immunoelectron microscopic analysis, and adherence to fibroblast cells. These results indicate that L. casei has acquired a new phenotype to bind fibronectin upon the expression of the fibronectin binding domain on the cell surface. This L. casei also shows binding affinity to fibrinogen, indicating that fibronectin binding domain is involved in the binding to fibrinogen as well.

Colonization of the stratified squamous epithelium of the nonsecreting area of horse stomach by lactobacilli

Selective adhesion to only certain epithelia is particularly common among the bacterial members of the indigenous microflora of mammals. We have found that the stratified squamous epithelium of the nonsecreting area of horse stomach is colonized by gram-positive rods. The microscopic features of a dense layer of these bacteria on the epithelium were found to be similar to those reported in mice, rats, and swine. Adhering microorganisms were isolated and identified as Lactobacillus salivarius, L. crispatus, L. reuteri, and L. agilis by DNA-DNA hybridization and 16S rRNA gene sequencing techniques. These lactobacilli associated with the horse, except for L. reuteri, were found to adhere to horse epithelial cells in vitro but not to those of rats. A symbiotic relationship of these lactobacilli with the horse is suggested.

Generation of polymeric immunoglobulin receptor-deficient mouse with marked reduction of secretory IgA

We generated mouse lacking exon 2 of polymeric Ig receptor (pIgR) gene by a gene-targeting strategy (pIgR-deficient mouse; pIgR-/- mouse) to define the physiological role of pIgR in the transcytosis of Igs. pIgR-/- mice were born at the expected ratio from a cross between pIgR+/- mice, indicating that disruption of the pIgR gene in mice is not lethal. pIgR and secretory component proteins were not detected in pIgR-/- mice by Western blot analysis. Moreover, immunohistochemical analysis showed that pIgR protein is not expressed in jejunal and colonic epithelial cells of pIgR-/- mice, whereas IgA+ cells are present in the intestinal mucosa of pIgR-/- mice as well as wild-type littermates. Disruption of the pIgR gene caused a remarkable increase in serum IgA concentration and a slight increment of serum IgG and IgE levels, leaving serum IgM level unaltered. In contrast, IgA was much reduced but not negligible in the bile, feces, and intestinal contents of pIgR-/- mice. Additionally, IgA with a molecular mass of 280 kDa preferentially accumulated in the serum of pIgR-/- mice, suggesting that transepithelial transport of dIgA is severely blocked in pIgR-/- mice. These results demonstrate that dIgA is mainly transported by pIgR on the epithelial cells of intestine and hepatocytes, but a small quantity of IgA may be secreted via other pathways.

Polymeric immunoglobulin receptor gene of mouse: sequence, structure and chromosomal location

We have isolated genomic clones of a mouse gene (pIgR) for polymeric immunoglobulin receptor which mediates transport of polymeric immunoglobulins. The four overlapping clones obtained retain a DNA fragment spanning approx. 32 kb altogether, and the base sequences of these clones were determined. Comparison with cDNA sequence identified 11 exons and 10 introns, as well as a polyadenylation site. We have also identified presumptive regulatory elements on the 5' presumptive untranscribed region and a polyadenylation signal on the 3' untranslated region. Thus, the DNA cloned covers the whole area which is transcribed into mRNA. Also, in situ hybridization locates this gene on the long arm of the first chromosome of mouse.

Enterotoxin-binding glycoproteins in a proteose-peptone fraction of heated bovine milk

The binding of Escherichia coli heat-labile enterotoxin to caseins, whey proteins, milk fat globule membrane, and proteose-peptone fraction from bovine milk was studied by using the Western blot technique. Two toxin-binding glycoproteins, pp16k and pp20k, with molecular weights of 15,500 and 20,000, respectively, were detected only in a proteose-peptone fraction. These glycoproteins were partially purified by ammonium sulfate precipitation and Toyopearl HW 55 gel filtration chromatography. The binding ability to the toxin was destroyed by periodate treatment or beta-galactosidase treatment, indicating that a carbohydrate moiety, particularly a terminal galactosyl residue, was essential for the binding of the toxin. In contrast, the binding ability was not changed by mild acid treatment, and these glycoproteins did not bind cholera toxin, which can bind to ganglioside GM1, suggesting that the carbohydrate structure of the glycoproteins is different from that of GM1. The N-terminal amino acid sequence and immunoblot analysis indicated that the protein moieties of pp16k and pp20k are identical to alpha-lactalbumin and beta-lactoglobulin, respectively. These toxin-binding glycoproteins were not detected in whey proteins isolated from unheated skim milk, suggesting that they are newly generated during heat treatment of skim milk before the preparation of a proteose-peptone fraction.

Molecular cloning, nucleotide sequence and expression of the tufB gene encoding elongation factor Tu from Thermus thermophilus HB8

The tufB gene encoding elongation factor Tu (EF-Tu) of Thermus thermophilus HB8 was cloned and expressed. Compared with the known tufA gene of T. thermophilus, nucleotide differences were found at 10 positions out of 1221 nucleotides, and amino acid substitutions were found at 4 positions out of 406 amino acids. The tufB product was 70.9% homologous to the corresponding sequence of the tufB product of E. coli. The G+C content of the third base of the codon in the tufB gene was 84.8% and G was especially preferred in this position.