Egg-laying-hormone immunoreactivity in the neural ganglia and ovary of Haliotis asinina Linnaeus

Immunoreactivity against the abalone egg-laying hormone (aELH) was detected in the fine granules of type 1 and 2 neurosecretory (NS) cells, neurites in the neuropil, and blood sinuses in the connective tissue sheath of the cerebral, pleuropedal, and visceral ganglia of the tropical abalone, Haliotis asinina Linnaeus. The number of positive NS cells, and the intensity of staining in the ganglia, varied and might be related to the stage of ovarian cycle. At any stage, positive cells were most numerous in the pleuropedal, and least numerous in the visceral ganglion. In addition, several cells of the statocyst and associated nerves also exhibited the immunoreactivity. In the ovary, the most intense reactivity was detected in the follicular and granular cells adjacent to mature oocytes, in the trabeculae and the ovarian capsule. The cytoplasm of mature oocytes was also moderately stained. The results indicate that the cerebral, pleuropedal, and visceral ganglia are the main sites of aELH-producing cells. The ovary may also produce aELH locally.

Calcinosis circumscripta in the dog: a retrospective pathological study

Calcinosis circumscripta is an uncommon syndrome of ectopic idiopathic, dystrophic, metastatic or iatrogenic mineralization characterized by deposition of calcium salts in soft tissues. This paper is a retrospective study of 77 canine cases. The age of dogs in the study varied from 4 months to 15 years and 55% were <1 year old, 74% <2 years old and 88% <4 years old. Several pure and mixed, typically large breed dogs were affected so that 28.6, 13 and 9% were German Shepherd, Rottweiler and Labrador Retriever respectively. The size of lesions varied from 2 mm to 13 cm in diameter but most lesions were between 0.5 cm and 3 cm in diameter. Lesions were solitary in 82% of the affected dogs, and occurred most commonly on the hind feet (50%) and tongue (23%). With multiple lesions there was no apparent body symmetry. Microscopically, most lesions were well-defined single or multiple variably sized aggregates of amorphous to granular, lightly to darkly basophilic material with or without peripheral granulomatous reaction and surrounded by varying amounts of fibrous connective tissue. Additionally, three small nodular masses in the wall of the jejunum of a dog were diagnosed as calcinosis circumscripta. This is the first reported case of idiopathic intestinal calcinosis circumscripta in the dog.

A phase I study of oral ZD 1839 given daily in patients with solid tumors: IND.122, a study of the Investigational New Drug Program of the National Cancer Institute of Canada Clinical Trials Group

PURPOSE

To define the maximum tolerated dose (MTD), the dose limiting toxicity (DLT), the biological active (BA) dose and the pharmacokinetics (PK) of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor ZD1839 (Iressa) when administered continuously as a once daily dose in patients with advanced, incurable solid tumours.

PATIENTS AND METHODS

Twenty-eight patients were enrolled in cohorts of three from three National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) centers. ZD1839 was given at doses from 150 to 800 mg daily orally and patients underwent a pretreatment and a 28 day post treatment tumor biopsy, while PK sampling was performed on days 8, 15, 22, 29, and a toxicity assessment every 28 days.

RESULTS

All twenty-eight patients were evaluable for non-hematological and hematological toxicity. Twenty-seven were evaluable for response. The MTD was not reached but DLT included reversible rash and diarrhea. One patient with urachal cancer had a transient 55% decrease in tumor size and two other patients (breast and non-small cell lung cancer) had minor responses; three additional patients had pharmacodynamic evidence of target effect. PK demonstrated steady state within the first 2 weeks of dosing and dose dependent exposure.

CONCLUSION

It appears that ZD 1839 at a dose of 800 m/day was tolerable, although some patients required dose modification for diarrhea. Doses above 250 m/day demonstrate biologic activity and could be consider for future study in a variety of EGFR positive tumor types.

Crystal structure of the anthrax lethal factor

Lethal factor (LF) is a protein (relative molecular mass 90,000) that is critical in the pathogenesis of anthrax. It is a highly specific protease that cleaves members of the mitogen-activated protein kinase kinase (MAPKK) family near to their amino termini, leading to the inhibition of one or more signalling pathways. Here we describe the crystal structure of LF and its complex with the N terminus of MAPKK-2. LF comprises four domains: domain I binds the membrane-translocating component of anthrax toxin, the protective antigen (PA); domains II, III and IV together create a long deep groove that holds the 16-residue N-terminal tail of MAPKK-2 before cleavage. Domain II resembles the ADP-ribosylating toxin from Bacillus cereus, but the active site has been mutated and recruited to augment substrate recognition. Domain III is inserted into domain II, and seems to have arisen from a repeated duplication of a structural element of domain II. Domain IV is distantly related to the zinc metalloprotease family, and contains the catalytic centre; it also resembles domain I. The structure thus reveals a protein that has evolved through a process of gene duplication, mutation and fusion, into an enzyme with high and unusual specificity.

Laparoscopic fundoplication for symptomatic but physiologic gastroesophageal reflux

Esophageal pH monitoring identifies some patients who have physiologic amounts of esophageal acid exposure but have a strong correlation between symptoms of esophageal reflux events. These patients with symptomatic physiologic reflux probably have enhanced sensory perception of reflux events and may be difficult to control with acid-suppressive therapy. Little is known about the role of fundoplication in such patients. Patients with no endoscopic evidence of gastroesophageal reflux disease and a normal 24-hour pH composite score (<22.4 in our laboratory), but a symptom index (SI = number of symptoms with pH <4/total number of symptoms) greater than 50% were offered laparoscopic fundoplication if acid-suppressive therapy was unsatisfactory. This group comprised 18 (4%) of 459 patients undergoing fundoplication at our institution. Heartburn, dysphagia, and reflux symptoms were scored on a scale of 0 to 10 with patients on and off medicine preoperatively, and at a mean of 7.2 months (range 1 to 32 months) postoperatively. The 18 patients with symptomatic physiologic reflux (6 males and 12 females) had heartburn as a major complaint. Preoperative response to proton pump inhibitors for heartburn was 72% and for all symptoms was 60%. The group had a mean pH composite score of 14 (range 4 to 22). The symptom used to calculate the symptom index was heartburn in 12 patients, regurgitation in three, chest pain in two, and cough in one. An average of 18 symptoms (range 2 to 56) were recorded. The mean symptom index was 82% (range 50% to 100%). A Nissen fundoplication was performed in nine patients and a Toupet fundoplication in nine. Surgery was successful (>90%) in alleviating reflux symptoms in 14 patients and partially successful (>75%) in three of the remaining four patients. Gas bloat and dysphagia were seen in one patient each. Fundoplication is effective at relieving reflux symptoms in carefully selected patients with symptomatic physiologic reflux, with minimal side effects.

Congenital hepatic fibrosis in calves

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Patterns of success and failure with laparoscopic Toupet fundoplication

BACKGROUND

Advocates of the Toupet partial fundoplication claim that the procedure has a lower rate of the side effects of dysphagia and gas bloat than a complete Nissen fundoplication. However, there is increasing recognition that reflux control is not always as good with the Toupet procedure as with the Nissen. Therefore, we set out to evaluate the factors contributing to success and failure in patients who underwent laparoscopic modified Toupet fundoplication (LTF).

METHODS

A total of 143 patients undergoing LTF for documented gastroesophageal reflux disease (GERD) were evaluated prospectively in regard to their outcomes over a 4-year period. All patients had preoperative esophagogastroduodenoscopy (EGD) and manometry; 24-h pH testing was used selectively. Esophageal manometry was requested of all patients 6 weeks postoperatively. Clinical follow-up was by office visit or questionnaire every 6 months after surgery; patients with significant problems were investigated further. Failure was defined as the development of recurrent reflux documented by endoscopy, 24-h pH test, or wrap disruption on barium swallow, or severe dysphagia persisting >3 months and requiring surgical revision.

RESULTS

At a mean follow-up of 30 months (range, 3-51), 21 of 143 patients failed LTF; two had dysphagia and 19 had recurrent reflux. Failure was associated with preoperative findings of a defective lower esophageal sphincter (LES) (14/21), complicated esophagitis (13/21), and failure to divide short gastric vessels (12/19) (chi-square p < 0.05). Defective esophageal body peristalsis, present in 14 patients, resulted in failure in six cases. Presence of either complicated esophagitis or a defective LES was associated with a 3-year 50% success rate, whereas presence of mild esophagitis and a normal LES was reflected in a 96% 3-year success rate.

CONCLUSION

Laparoscopic Toupet fundoplication should be reserved for milder cases of GERD, as assessed by manometry and endoscopy.

Cutaneous mucinosis and mastocytosis in a shar-pei

A 7-year-old shar-pei was presented because of a recurrent dermatologic condition. Skin biopsies revealed an idiopathic (primary) cutaneous mucinosis that initially responded to corticosteroids. The condition reappeared 2 years later and subsequent biopsies revealed a mast cell tumor in some of the skin sites previously diagnosed with mucinosis.

Lethal toxin actions and their consequences

After entry of infectious anthrax spores into the body, host-specific signals induce spore germination, outgrowth of vegetative bacilli and the expression of lethal toxin and other virulence factors. Anthrax lethal toxin (LeTx) is a virulence factor responsible for the major pathologies seen during systemic anthrax infections. Injection of sterile LeTx into test animals mimics the shock and sudden death seen during active bacterial infections. Once large levels of LeTx are produced within the body, destruction of bacteria by administration of antibiotics is usually unsuccessful. The LeTx is believed to be secreted into the bloodstream where it circulates freely throughout the body and binds and enters host cells. Once in the cytoplasm, the lethal factor acts as a zinc-metalloprotease disrupting normal homoeostatic functions. Macrophages are a uniquely sensitive cell type that seem to be vital global mediators of toxin-induced pathologies. Removal of macrophages from mice renders them insensitive to LeTx challenge. Low levels of lethal toxin induce macrophage production, in vitro, of the shock-inducing cytokines TNF and Il-1beta. Higher levels of LeTx cause over-production of reactive oxygen intermediates, bursting of macrophages and release of mediators of shock. We believe that agents capable of blocking key steps of the lethal toxin cascade may prove useful in combating anthrax pathologies.

Crystallographic studies of the anthrax lethal toxin

Anthrax lethal toxin comprises two proteins: protective antigen (PA; MW 83 kDa) and lethal factor (LF; MW 87 kDa). We have recently determined the crystal structure of the 735-residue PA in its monomeric and heptameric forms (Petosa et al. 1997). It bears no resemblance to other bacterial toxins of known three-dimensional structure, and defines a new structural class which includes homologous toxins from other Gram-positive bacteria. We have proposed a model of membrane insertion in which the water-soluble heptamer undergoes a substantial pH-induced conformational change involving the creation of a 14-stranded beta-barrel. Recent work by Collier's group (Benson et al. 1998) lends strong support to our model of membrane insertion. 'Lethal factor' is the catalytic component of anthrax lethal toxin. It binds to the surface of the cell-bound PA heptamer and, following endocytosis and acidification of the endosome, translocates to the cytosol. We have made substantial progress towards an atomic resolution crystal structure of LF. Progress towards a structure of the 7:7 translocation complex between the PA heptamer and LF will also be discussed.

Hypoadrenocorticism in young related Nova Scotia duck tolling retrievers

Five cases of hypoadrenocorticism in young related Nova Scotia duck tolling retrievers are discussed. Two were littermates and the others shared one or more common ancestors. No specific mode of inheritance was determined. Clinical and laboratory findings typical of hypoadrenocorticism were observed. Further documentation will be required to confirm a breed predisposition.

Mange induced by Trixacarus caviae in a guinea pig

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Clinical and manometric results of laparoscopic partial (Toupet) and complete (Rosetti-Nissen) fundoplication

It is unclear whether a partial or complete gastric fundoplication done laparoscopically will offer the best control of reflux with the fewest side effects. Prospective evaluation of laparoscopic Rosetti-Nissen (360) and Toupet (180) fundoplication was performed with assessment of clinical and manometric data.

METHODS

Patients with severe gastroesophageal reflux referred for surgical correction underwent preoperative motility and upper endoscopy. A Rosetti-Nissen or Toupet fundoplication was then performed laparoscopically. Short gastrics were not divided. No bougie was used in the Toupet, which was sutured intracorporeally. A 2-cm, loose, floppy wrap about a 50-Fr bougie was performed in the Nissen. Eleven patients underwent Rosetti-Nissen and 11 Toupet fundoplication. Mean ages, duration symptoms, weight, and baseline LES, were not different. Preop esophagitis grades were similar, as were Visick Scores and presence of dysphagia.

RESULTS

Visick scores at 6 months were better in the Toupet group than the Rosetti-Nissen (P = 0.07). Persistent Dysphagia in four, Gas-Bloat in two, and Odynophagia in one within the Rosetti-Nissen group accounted for the difference, and were not seen in Toupets. LES pressures differed significantly pre and postop (P < 0.001). The change in LES pressure was significantly different between Toupet and Rosetti-Nissen (chart). Seven patients had postop 24-h pH tests; all had no reflux. Three Rosettis have required revision to Toupet, with resolution of their symptoms.

CONCLUSIONS

In patients with severe GERD, laparoscopic Toupet and Rosetti-Nissen control symptoms and esophageal pH similarly. LES pressures are higher postop in the Rosetti-Nissen. Dysphagia and gas-bloat are more prevalent in the Nissen group. Laparoscopic Toupet fundoplication may be superior to Rosetti-Nissen in reducing the frequency of side effects frequently associated with antireflux surgery, yet with equal control of reflux.

Adult respiratory distress syndrome in a dog with necrotizing pancreatitis

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Severe psoroptic mange and endoparasitism in a Nubian doe

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Interstitial pneumonia in piglets on Prince Edward Island

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Percutaneous transabdominal hepatic needle biopsies in dogs

Ninety-six (4/dog) percutaneous transabdominal hepatic needle biopsy specimens were obtained from 24 dogs each weighing 10 to 24 kg. Two biopsies were performed in each dog prior to and 5 days after hepatopathy was experimentally induced. Information pertaining to the difficulty encountered in obtaining hepatic tissue is reported for the first of each pair of biopsies. All specimens were of diagnostic quality for light and electron microscopic evaluation. Adverse consequences (morbidity or mortality) resulting from the biopsy technique were not observed by monitoring of vital signs in the immediate postprocedure period and at 4 weeks. Recovery to an ambulatory state was seen in less than or equal to 30 minutes, except in 1 dog, in which prolonged recovery was attributed to acetylpromazine-induced hypotension.

Influence of neurophysin residues 1-8 on the optical activity of neurophysin-peptide complexes. Direct evidence that the 1-8 sequence alters the environment of bound peptide

Circular dichroism was used to compare the environment of peptides bound to native and des 1-8 neurophysin in order to further elucidate the role of the neurophysin 1-8 sequence in peptide-binding. A very large positive ellipticity (approximately 6000 deg cm2 dmol-1), shown earlier to be induced in tyrosine at position 2 of peptides bound to the native protein, was determined by the present study to be paralleled by similar induced changes in tyrosine at peptide position 1. Deletion of the neurophysin 1-8 sequence led to loss of half of the induced optical activity at peptide positions 1 and 2 and changes in binding-induced optical activity in the protein, the latter partially assignable to protein disulfides. In the mononitrated native and des 1-8 proteins, the optical activity of neurophysin Tyr-49, a residue at the peptide-binding site, was reduced by 80% in complexes of the des 1-8 protein relative to those of the native protein. The results suggest a role for neurophysin Arg-8 in modulating the optical activity at the binding site by directly placing a charge proximal to the binding site and/or by altering binding site conformation. The data provide the first unambiguous evidence of a difference in the environment of bound peptide between the native and des 1-8 proteins.