Chemoselective Oxidation of Thiols with Oxoammonium Cations

The oxidation of various aryl and aliphatic thiols with the commercially available and environmentally benign reagent Bobbitt's salt (1) has been investigated. The reaction affords the corresponding disulfide products in good to excellent yields (71-99%) and can be accomplished in water, methanol, or acetonitrile solvent. Moreover, the process is highly chemoselective, tolerating traditionally oxidation-labile groups such as free amines and alcohols. Combined experimental and computational studies reveal that the oxidation takes place via a polar two-electron process with concomitant and unexpected deoxygenation of the oxoammonium cation through homolysis of the weak N-O bond, differing from prototypical radical-based thiol couplings. This unusual consumption of the oxidant has significant implications for the development of new nitroxide-based radical traps for probing S-centered radicals, the advancement of new electrochemical or catalytic processes involving nitroxide/oxoammonium salt redox couples, and applications to biological systems.

Manganese enhanced magnetic resonance imaging in type 1 and type 2 diabetes mellitus

Background

The pathophysiology of diabetic cardiomyopathy has yet to be established although pre-clinical studies suggest a role for altered myocardial calcium handling. Manganese-enhanced magnetic resonance imaging (MEMRI) is a novel non-invasive method of assessing in vivo myocardial calcium handling.

Purpose

To investigate whether myocardial calcium handling is impaired in patients with either type 1 or type 2 diabetes mellitus in the absence of underlying heart disease.

Methods

In a prospective case-control study, patients with type 1 (n=19) or type 2 (n=10) diabetes mellitus and healthy volunteers (n=15) underwent MEMRI. Participants with prior coronary artery disease, cardiomyopathy or an abnormal electrocardiogram were excluded. Manganese dipyridoxyl diphosphate (0.1 mL/kg) was administered over 10 min and myocardial T1 mapping was performed prior to and every 2.5 min for 30 min after contrast infusion (Figure 1). Quantitative manganese uptake analysis was performed by measuring T1 relaxation times in a region of interest within the interventricular septum and compared to the left ventricular blood pool. The rate of myocardial manganese uptake was determined by Patlak modelling [1].

Results

Participants with type 1 and type 2 diabetes mellitus were older (50±13 and 55±15.3 years) than the healthy volunteers (32±10 years). All participants had preserved left ventricular ejection fraction (type 1 diabetes mellitus, 67.7±6.1%; type 2 diabetes mellitus, 66.8±3.2%; healthy volunteers, 65±3.5%). Mean myocardial manganese uptake was reduced in participants with both type 1 (6.4±0.6 mL/100 g of tissue/min) and type 2 (6.4±0.5 mL/100 g of tissue/min) diabetes mellitus compared with healthy volunteers (8.3±0.5 mL/100 g of tissue/min; p<0.0001 for both, Figure 2). There were no differences in myocardial manganese uptake between those with type 1 or type 2 diabetes mellitus (p=0.22). There was no statistically significant correlation between myocardial manganese uptake and age in the study population (r=−0.28, p=0.07).

Conclusion

Using MEMRI, we have demonstrated that myocardial calcium handling is impaired in patients with either type 1 or type 2 diabetes mellitus even in the absence of left ventricular systolic dysfunction. This suggests altered myocardial calcium handling may underlie, or contribute to, diabetic cardiomyopathy which has implications developing novel therapeutic targets for the prevention and treatment of diabetic cardiomyopathy.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): British Heart Foundation - Clinical Research Training Fellowship (FS/CRTF/20/24087)AstraZeneca - Investigator initiated award (ESR-19-20118)

Baseline inventory of Amphibians and reptiles in the vicinity of Kurupukari, Guyana

The habitat in the vicinity of Kurupukari, on the Essequibo River in central Guyana, is tall evergreen lowland forest. The area has suffered some human disturbance from agriculture, road construction and ferry activity. The area was sampled for 10 days in 1990 and 12 days in 1997; seven days in rainy season and 15 in dry season. During this sampling 23 anuran and 17 reptile species were collected. Some differences exist between species collected on either side of the river. Comparisons are made with collections from other locations in Guyana.

Preliminary Checklist of Amphibians and Reptiles from Baramita, Guyana

We provide an initial checklist of the herpetofauna of Baramita, a lowland rainforest site in the Northwest Region of Guyana. Twenty-five amphibian and 28 reptile species were collected during two separate dry-season visits. New country records for two species of snakes are documented, contributing to the knowledge on the incompletely known herpetofauna of Guyana.

Amphibians and Reptiles from Paramakatoi and Kato, Guyana

We report the herpetofauna of two neighboring upland locations in west-central Guyana. Twenty amphibian and 24 reptile species were collected. Only 40% of amphibians and 12.5% of reptiles were collected in both locations. This is one of the few collections made at upland (750–800 m) locations in the Guiana Shield.

The impact of conservation on the status of the world's vertebrates

Using data for 25,780 species categorized on the International Union for Conservation of Nature Red List, we present an assessment of the status of the world's vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: On average, 52 species of mammals, birds, and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth again as much in the absence of these. Nonetheless, current conservation efforts remain insufficient to offset the main drivers of biodiversity loss in these groups: agricultural expansion, logging, overexploitation, and invasive alien species.

Intrasphincteric botulinum toxin versus pneumatic dilatation for achalasia: a cost minimization analysis

BACKGROUND

Pneumatic dilatation or intrasphincteric botulinum toxin injection provide effective symptom relief for patients with achalasia. Although intrasphincteric botulinum toxin injection is simple and safe, its efficacy may be short-lived. Pneumatic dilatation lasts longer, but esophageal perforation is a risk. We compared treatment costs for pneumatic dilatation and intrasphincteric botulinum toxin injection using a decision analysis model to determine whether the practical advantages of intrasphincteric botulinum toxin injection outweigh the economic impact of the need for frequent re-treatment.

METHODS

Probability estimates for intrasphincteric botulinum toxin injection were derived from published reports. Probability estimates for the pneumatic dilatation strategy were obtained by retrospective review of our 10-year experience using the Rigiflex dilator. Direct, "third-party payer" costs were determined in Canadian dollars.

RESULTS

Intrasphincteric botulinum toxin injection was significantly more costly at $5033 compared with $3608 for the pneumatic dilatation strategy, yielding an incremental cost of $1425 over the 10-year period considered. Sensitivity analysis showed that pneumatic dilatation is less expensive across all probable ranges of costs and probability estimates. The intrasphincteric botulinum toxin injection strategy is less costly if life-expectancy is less than 2 years.

CONCLUSIONS

Intrasphincteric botulinum toxin injection is more costly than pneumatic dilatation for the treatment of achalasia. The added expense of frequent re-treatment with intrasphincteric botulinum toxin injection outweighs the potential economic benefits of the safety of the procedure, unless life-expectancy is 2 years or less.

Species identification and phylogenetic relationships based on partial HSP60 gene sequences within the genus Staphylococcus

The phylogenetic relationships among 36 validly described species or subspecies within the genus Staphylococcus were investigated by cloning and sequencing their 60 kDa heat-shock protein (HSP60) genes using a set of universal degenerate HSP60 PCR primers. The cloned partial HSP60 DNA sequences from nine Staphylococcus aureus strains were highly conserved (97-100% DNA sequence similarity; mean 98%), indicating that the HSP60 gene of multiple isolates within the same species have little microheterogeneity. At the subspecies level, DNA sequence similarity among members of S. aureus, Staphylococcus schleiferi, Staphylococcus cohnii and Staphylococcus capitis ranged from 91 to 98%. At the interspecies level, sequence similarity among 23 distinct species of staphylococci ranged from 74 to 93% (mean 82%). By comparison, the highest sequence similarity of Bacillus subtilis and Escherichia coli with members within the genus Staphylococcus was only 70 and 59%, respectively. Importantly, phylogenetic analysis based on the neighbour-joining distance method revealed remarkable concordance between the tree derived from partial HSP60 gene sequences and that based on genomic DNA-DNA hybridization, while 16S rRNA gene sequences correlated less well. The results demonstrate that DNA sequences from the highly conserved and ubiquitous HSP60 gene offer a convenient and accurate tool for species-specific identification and phylogenetic analysis of staphylococci.

Cost-minimization analysis of piperacillin/tazobactam versus imipenem/cilastatin for the treatment of serious infections: a Canadian hospital perspective

BACKGROUND

In 1998 we reported the first Canadian double-blind, randomized, clinical trial involving a comparison of piperacillin/tazobactam (P/T) with imipenem/cilastatin (I/C). The present study was conducted to determine the feasibility of replacing I/C at our institution.

OBJECTIVE

To describe the outcome of a pharmacoeconomic analysis of the clinical trial from the perspective of a tertiary acute-care institution.

METHODS

A total of 150 consenting adults originally prescribed I/C were randomly assigned to receive either P/T 4.5 g i.v. (n = 75) or I/C 500 mg i.v. (n = 75) every six hours. Actual direct medical resources used in relation to the treatment of bacterial infections were prospectively assessed during a clinical trial; these included cost of study and ancillary antibiotics, hospitalization, diagnostic testing (radiology, laboratory assessments), and labor, as well as treatment of adverse drug reactions, antibiotic failures, and superinfections.

RESULTS

While costs for successful treatment courses were similar across treatment arms, hospitalization costs for treatment course failures were higher for P/T recipients. Direct medical costs for treatment courses associated with a superinfection were also higher in the P/T arm. Overall costs for treatment failures with either study drug were at least twofold those observed for successful treatment courses. Mean total management cost per patient in the P/T group was $15,211 ($ CDN throughout) (95% CI $11,429 to $18,993), compared with $14,232 (95% CI $11,421 to $17,043) in the I/C group (p = 0.32), resulting in a mean cost difference of $979. Sensitivity analyses revealed that the superiority of I/C over P/T for successful treatment of serious infections was sensitive to changes in the cost of hospitalization and drug efficacy for either drug.

CONCLUSIONS

Based on the results of the clinical trial, P/T and I/C offer similar clinical, microbiologic, and toxicity outcomes in hospitalized patients with serious infections. Under base-case conditions, our pharmacoeconomic analysis showed that I/C was a cost-effective alternative to P/T at the dosage regimens studied. However, this finding was sensitive to plausible changes in both clinical and economic parameters.

A cost-utility analysis comparing omeprazole with ranitidine in the maintenance therapy of peptic esophageal stricture

BACKGROUND

Recent studies have suggested that patients receiving omeprazole for prophylaxis against peptic esophageal stricture recurrence have less dysphagia and require fewer repeat dilations than patients receiving ranitidine.

OBJECTIVE

To estimate the incremental utility gain and associated incremental cost of omeprazole compared with those of ranitidine for the maintenance therapy of patients with peptic stricture who required esophageal dilation.

METHODS

Decision analysis using SMLTREE software was used to compare the incremental cost-utility of omeprazole 20 mg once daily with that of ranitidine 150 mg bid for one year. Variables were estimated from the literature, hospital data, and utility analyses involving patients with peptic stricture and health professionals. The primary outcome measure was cost per quality-adjusted life-years (QALYs) gained.

RESULTS

The incremental cost of omeprazole compared with that of ranitidine was $556 per patient treated. The incremental utility gain of omeprazole was 0.0112 QALYs. Overall, the incremental cost:utility ratio of omeprazole in the maintenance therapy of patients with peptic stricture was $49,600 per QALY gained. A sensitivity analysis revealed that the estimates with the greatest impact on the cost:utility ratio were disutility associated with dysphagia and dilation, the probability of requiring redilation and the cost of medications.

CONCLUSIONS

Omeprazole 20 mg once daily is associated with greater utility and higher cost than ranitidine 150 mg bid when used as prophylaxis against stricture recurrence. Omeprazole may be considered clinically and economically sufficient enough to warrant widespread use in this setting.

Pathophysiology and investigation of Barrett's esophagus

Barrett's esophagus is an acquired condition with columnar metaplasia of the distal esophagus. Gastroesophageal reflux is the main pathophysiological factor, although genetic predisposition may play a role. The significance of Barrett's esophagus is that it is the only recognized risk factor for adenocarcinoma of the esophagus, which is one of the most rapidly rising types of cancer in North America. Cancer develops in Barrett's esophagus through a series of steps including mucosal dysplasia. High grade dysplasia is clearly a premalignant lesion and has been the focus of endoscopic surveillance strategies. Because dysplasia and adenocarcinoma develop predominantly in patients with specialized intestinal columnar epithelium, they make up the group that would be considered for surveillance programs. Endoscopic surveillance for dysplasia is only indicated for patients in whom esophagectomy would be considered if high grade dysplasia or carcinoma was found, at least until other endoscopic ablative techniques are proven to be beneficial. It has been recommended that endoscopy be performed every other year and be increased to yearly if low grade dysplasia is found. High grade dysplasia should be confirmed by another expert pathologist, and the patient should then be considered for esophagectomy. Flow cytometry and genetic markers may improve the ability to select patients for surveillance programs in the near future.

Predictors for frequent esophageal dilations of benign peptic strictures

Recurrence of esophageal peptic stricture necessitating repeated dilation treatments remains a problem for many patients despite optimal acid suppressive therapy. The factors associated with frequent relapses are poorly understood. We studied retrospectively a population of 58 patients with benign peptic strictures and dysphagia treated by esophageal dilation and followed for 66.5 +/- 6.7 months. Data was collected for age, sex, heartburn, weight loss, esophagitis, Barrett's esophagus, number of dilation treatments during the first year of follow-up, frequency and number of subsequent dilation treatments, type of dilator used, and history of other concurrent treatments. Patients who lacked heartburn (P = 0.007) or who reported a history of weight loss (P = 0.006) at the time of their initial presentation required more frequent dilations during the first year of follow-up. The mean number of dilations in year 1 was 6.2 +/- 0.9 for patients lacking heartburn versus 3.2 +/- 0.5 for patients with heartburn (P = 0.004), and 9.0 +/- 1.8 for patients who reported weight loss versus 4.1 +/- 0.5 (P = 0.006) for those who did not. The patients requiring frequent treatment during their first year also required frequent subsequent dilations because of stricture recurrence (P < 0.0001). We did not demonstrate any relationship between the other factors studied and treatment frequency. These observations suggest that patients who require frequent retreatment for recurrent peptic stricture are more likely to provide a history of weight loss and less likely to complain of heartburn at initial presentation. The pattern of frequent repeat dilation for recurrent peptic strictures is established during the first year of follow-up.

HSP60 gene sequences as universal targets for microbial species identification: studies with coagulase-negative staphylococci

A set of universal degenerate primers which amplified, by PCR, a 600-bp oligomer encoding a portion of the 60-kDa heat shock protein (HSP60) of both Staphylococcus aureus and Staphylococcus epidermidis were developed. However, when used as a DNA probe, the 600-bp PCR product generated from S. epidermidis failed to cross-hybridize under high-stringency conditions with the genomic DNA of S. aureus and vice versa. To investigate whether species-specific sequences might exist within the highly conserved HSP60 genes among different staphylococci, digoxigenin-labelled HSP60 probes generated by the degenerate HSP60 primers were prepared from the six most commonly isolated Staphylococcus species (S. aureus 8325-4, S. epidermidis 9759, S. haemolyticus ATCC 29970, S. schleiferi ATCC 43808, S. saprophyticus KL122, and S. lugdunensis CRSN 850412). These probes were used for dot blot hybridization with genomic DNA of 58 reference and clinical isolates of Staphylococcus and non-Staphylococcus species. These six Staphylococcus species HSP60 probes correctly identified the entire set of staphylococcal isolates. The species specificity of these HSP60 probes was further demonstrated by dot blot hybridization with PCR-amplified DNA from mixed cultures of different Staphylococcus species and by the partial DNA sequences of these probes. In addition, sequence homology searches of the NCBI BLAST databases with these partial HSP60 DNA sequences yielded the highest matching scores for both S. epidermidis and S. aureus with the corresponding species-specified probes. Finally, the HSP60 degenerate primers were shown to amplify an anticipated 600-bp PCR product from all 29 Staphylococcus species and from all but 2 of 30 other microbial species, including various gram-positive and gram-negative bacteria, mycobacteria, and fungi. These preliminary data suggest the presence of species-specific sequence variation within the highly conserved HSP60 genes of staphylococci. Further work is required to determine whether these degenerate HSP60 primers may be exploited for species-specific microbic identification and phylogenetic investigation of staphylococci and perhaps other microorganisms in general.

Metastatic Crohn's disease

The case of a 25-yr-old female with Crohn's disease who developed recurrent erythematous nodules on her lower extremities is described. These modules enlarged and ulcerated. Repeated bacterial, fungal, and acid-fast cultures remained negative. A skin biopsy revealed non-caseating granulomata, confirming the diagnosis of cutaneous "metastatic" Crohn's disease. The lesions completely resolved with systemic corticosteroid therapy. Although cutaneous metastatic Crohn's disease is uncommon, patients with Crohn's disease who develop unusual skin lesions that persist should have them biopsied.

Macroscopic healing of esophagitis does not improve esophageal motility

The purpose of the present study was to prospectively determine if healing of esophagitis as assessed by endoscopy results in improved esophageal motility. Thirty-one patients with erosive esophagitis who were randomized to receive either omeprazole 20 mg once daily or placebo completed the double-blind study. All patients underwent endoscopy and esophageal motility before treatment and at four weeks after treatment. Twenty-two healthy volunteers underwent esophageal manometry and served as normal controls. Manometric tracings were coded, randomized, and analyzed blindly. Compared to normal controls, patients with esophagitis had significantly lower LESP, decreased amplitude of peristaltic contractions, and increased occurrence of abnormal contractions. Omeprazole was superior to placebo in healing of esophagitis. However, healing of esophagitis was not associated with any improvement in esophageal motility. The manometric data suggest that the motility disturbance seen in esophagitis is not secondary to the esophagitis but rather a primary phenomenon. The lack of improvement of esophageal motility with healing may explain the high recurrence of esophagitis in clinical trials following discontinuation of omeprazole.

Experimental murine cytomegalovirus infection in severe combined immunodeficient mice

Severe combined immunodeficient (scid) and BALB/c mice were experimentally infected with murine cytomegalovirus (MCMV). Scid mice infected by the intraperitoneal route died or were moribund at dose-dependent times ranging from 12 to 13 days after inoculation for > or = 3.00 x 10(4) plaque forming units (pfu) of virus to 25 days for 1.17 x 10(2) pfu. Histologic lesions included severe adrenal necrosis at low doses and splenic necrosis at high doses. Multinucleate hepatocytes with multiple inclusion bodies were observed at all doses. In visceral organs, the inflammatory response consisted of cell necrosis and neutrophil infiltration. Scid mice infected with 1.00 x 10(3) pfu by the intranasal route were moribund by 24 or 25 days after inoculation. Viral titers in tissues examined from these mice increased in all organs examined until they became moribund. BALB/c mice infected intranasally had detectable virus titers in the adrenal glands, salivary glands, lungs, and spleen by 7 or 14 days after inoculation, but decreased thereafter. These mice remained clinically normal through the infection. In BALB/c mice, histologic lesions were present only in the salivary glands.

The effect of differential vagal nerve cooling on feline esophageal function

Studies were performed on four cats to examine the effects of differential vagal nerve cold blockade on the upper esophageal sphincter, esophageal peristalsis, and swallow-induced lower esophageal sphincter relaxation. Reversible vagal nerve blockade was accomplished by cooling the cervical nerve trunks. Pressures were measured using multi-lumen manometry tubes. Upper esophageal sphincter pressure (resting and response to intraesophageal balloon distention), primary peristalsis, secondary peristalsis induced by intraesophageal balloon distention, and swallow-induced lower esophageal sphincter relaxation were evaluated at each temperature level, with vagal cooling from 20 degrees C to 0 degree C by 0.5 degree C decrements. Primary and secondary peristalsis were abolished at the same temperature. Swallow-induced lower esophageal sphincter relaxation was abolished at the same temperature that peristalsis was abolished. Upper esophageal sphincter pressure decreased by at least 25% at the same temperature that secondary peristalsis was abolished. Balloon distention-induced increase in upper esophageal sphincter pressure was not abolished prior to the decrease in resting pressure and, in the majority of experiments, was not abolished at any time during differential cooling. Prolonged complete vagal nerve blockade experiments demonstrated transient abolition and then return of balloon distention-induced reflex upper esophageal sphincter contraction. We conclude that: 1) differential vagal cooling does not allow separation of the contribution of different vagal fibres such as afferent vs efferent or excitatory versus inhibitory; 2) there is dual afferent innervation from the proximal cervical esophagus, allowing persistence of intraesophageal balloon distention-induced upper esophageal sphincter contraction during prolonged vagal cervical trunk blockade.

Adverse effects with oral 5-aminosalicyclic acid

Two patients with ulcerative colitis and a past history of allergic reactions to sulfasalazine had similar reactions when treated with 5-aminosalicylic acid. This suggests that, at least in some patients, the adverse effects of sulfasalazine are due to 5-aminosalicylic acid rather than sulfapyridine. Desensitization to sulfasalazine was successfully carried out in one patient but was not attempted in a second.

Influence of cortisol on prostaglandin synthesis by fetal membranes, placenta, and uterus of pregnant rabbits

Two experiments were designed to assess the effects of cortisol on prostaglandin formation in amniotic fluid and the prostaglandin-forming cyclooxygenase in 4 gestational tissues of rabbits. Cortisol treatment (12 mg/kg body wt/h) was initiated on Day 21 of pregnancy and continued for a 24-h period. Each experiment included 5 treated and 5 vehicle-injected controls, killed at 48 (Experiment 1) or 62 h (Experiment 2) after initial injection. In both experiments, amniotic fluid was collected; cortisol, prostaglandin F (PGF), and prostaglandin E2 (PGE2) were quantified by radioimmunoassay. Microsomes prepared from amnion, yolk sac splanchnopleure, uterus, and placenta were analyzed for prostaglandin-forming cyclooxygenase activity. In Experiment 2, blood drawn at 12-h intervals was quantified for PGF, PGE2, and progesterone. In cortisol-treated rabbits, plasma progesterone decreased (p less than 0.01) from 7.2 +/- 0.8 ng/ml on Day 21 (pre-treatment) to 1.6 +/- 0.2 ng/ml on Day 23, 48 h after the initiation of cortisol treatment. By 62 h, PGF, PGE2, and cortisol concentrations were all significantly higher (p less than 0.05) in the amniotic fluid of treated animals. However, prostaglandin-forming cyclooxygenase activity had not increased in most fetal or maternal tissues at either 48 or 62 h. Therefore, even though increased prostaglandin production may be responsible for the cortisol-induced abortion, increased cyclooxygenase activity in the fetal membranes, placenta, or uterus probably is not the primary stimulus for the increased prostaglandin synthesis.

Analysis of E. coli promoter sequences

We have compiled and analyzed 263 promoters with known transcriptional start points for E. coli genes. Promoter elements (-35 hexamer, -10 hexamer, and spacing between these regions) were aligned by a program which selects the arrangement consistent with the start point and statistically most homologous to a reference list of promoters. The initial reference list was that of Hawley and McClure (Nucl. Acids Res. 11, 2237-2255, 1983). Alignment of the complete list was used for reference until successive analyses did not alter the structure of the list. In the final compilation, all bases in the -35 (TTGACA) and -10 (TATAAT) hexamers were highly conserved, 92% of promoters had inter-region spacing of 17 +/- 1 bp, and 75% of the uniquely defined start points initiated 7 +/- 1 bases downstream of the -10 region. The consensus sequence of promoters with inter-region spacing of 16, 17 or 18 bp did not differ. This compilation and analysis should be useful for studies of promoter structure and function and for programs which identify potential promoter sequences.

The upper esophageal sphincter in the cat: the role of central innervation assessed by transient vagal blockade

Studies were performed on four cats to assess the role of extrinsic innervation via the cervical nerve trunks in the control of upper esophageal sphincter function. Transient vagal nerve blockade was accomplished by cooling the cervical vagosympathetic nerve trunks previously isolated in skin loops on each side of the neck. Upper esophageal sphincter pressure was measured using a multilumen oval manometry tube and a rapid pull-through technique. The upper esophageal sphincter response to cervical intraesophageal balloon distention and acid perfusion was assessed. The feline upper esophageal sphincter has a distinct asymmetric pressure profile, whereby anterior pressure greater than posterior pressure greater than left pressure greater than right pressure. Bilateral vagal nerve blockade lowered the mean upper esophageal sphincter pressure from 18.5 +/- 1.5 to 12.0 +/- 2.8 mmHg (1 mmHg = 133.3 Pa) (p less than 0.001), with a significant reduction in pressure in all four quadrants. Intraesophageal balloon distention and acid perfusion both produced a significant increase in upper esophageal sphincter pressure. Bilateral vagal nerve blockade completely abolished the response of the upper esophageal sphincter to balloon distention and acid perfusion. We conclude that normal upper esophageal sphincter tone in the cat is partially mediated by excitatory neural input via the cervical nerve trunks, presumably via the recurrent laryngeal nerves; and cervical intraesophageal balloon distention and acid perfusion produce reflex contraction of the upper esophageal sphincter, which is dependent on neural pathways via the cervical vagal nerve trunks, but the relative contribution of afferent and efferent pathways remains unknown.

Gastric and duodenal motility in the cat: the role of central innervation assessed by transient vagal blockade

Experiments were performed on four cats to characterize fasting gastric and small bowel motility and to assess the role of extrinsic vagal innervation in the control of that motor activity. A multilumen manometry tube was positioned to record pressure changes from the proximal small bowel and stomach. Transient vagal nerve blockade was accomplished by cooling the cervical vagosympathetic nerve trunks, previously isolated in skin loops on each side of the neck. Two characteristic patterns of basal activity were documented in the stomach: (i) regular phasic contractions of variable amplitude in the body of the stomach; and (ii) infrequent, irregular contractions of high amplitude in the distal antrum. In the duodenum, two predominant activity patterns were noted: (i) periods of continuous irregular activity; and (ii) irregular clusters of contractions separated by quiescent intervals. No typical migrating motor complex activity was seen in the basal gastric or small bowel recordings. Bilateral vagal blockade did not consistently change the general pattern of gastric or small bowel activity, but did appear to reduce gastric contractile activity, as measured by motility indices. We conclude that extrinsic vagal innervation does not play a major role in the control of fasting feline gastric and duodenal motility.

Manometric study of a ruminator

Rumination is an uncommon disorder with controversial pathophysiology. We have studied a classic ruminator with esophageal, gastric, and small bowel motility techniques during episodes of voluntary regurgitation. His regurgitation was accompanied by simultaneous positive pressure deflections in multiple locations in the stomach, simultaneous negative pressure deflections in multiple locations in the esophagus followed rapidly by simultaneous positive pressure deflections, brief (1-second) periods of lower esophageal sphincter relaxation, and deep inspiratory movements. No intrinsic abnormalities of esophageal, gastric, or small bowel motility were present. We conclude that regurgitation in a ruminator is triggered by a Mueller experiment (forced inspiration against a closed glottis).

Oesophageal peristalsis in the cat: the role of central innervation assessed by transient vagal blockade

Studies were performed on five cats to assess the role of extrinsic vagal innervation in the control of peristalsis in the smooth muscle oesophagus. Transient vagal nerve blockade was accomplished by cooling the cervical vagosympathetic nerve trunks previously isolated in skin loops on each side of the neck. Peristalsis throughout the body of the oesophagus was monitored using a continuously perfused multilumen manometry tube. Striated and smooth muscle portions of the esophagus were delineated by abolishing smooth muscle activity with atropine. Secondary peristalsis was assessed by intra-oesophageal balloon distension studies. The threshold volume for balloon-induced secondary peristalsis was lower in the smooth muscle oesophagus. Unilateral vagal blockade reduced the incidence of primary and secondary peristalsis in the striated muscle oesophagus but not in the smooth muscle oesophagus. Bilateral vagal nerve blockade abolished primary swallow-induced peristalsis and secondary peristalsis in both the smooth and striated muscle cat oesophagus. Administration of cholinergic agents or adrenergic blocking agents failed to restore secondary peristalsis in the smooth muscle oesophagus during vagal cooling. We conclude that connections to the central nervous system via the vagal nerve trunks are required for normal secondary as well as primary peristalsis in both the smooth and striated muscle portions of the cat oesophagus.

Lower esophageal sphincter function in the cat: role of central innervation assessed by transient vagal blockade

Studies were performed on four cats to assess the role of extrinsic vagal innervation in the control of lower esophageal sphincter (LES) function. Both cervical vagal nerves were blocked transiently by cooling. LES pressure was measured using a multilumen manometry tube. LES relaxation was assessed during intraesophageal balloon distension in both the striated and smooth muscle portions of the esophagus. Bilateral vagal nerve blockade lowered the mean LES pressure from 58 +/- 17 to 29 +/- 9 mmHg (P less than 0.01). During vagal blockade, balloon distension in the striated muscle esophagus further reduced sphincter pressure to 16 +/- 4 mmHg (P less than 0.01) and that in the smooth muscle esophagus to 15 +/- 3 mmHg (P less than 0.01). Swallow-induced LES relaxation was abolished during bilateral vagal nerve blockade. During vagal blockade, atropine reduced LES pressure to 10 +/- 1 mmHg, phentolamine to 13 +/- 6 mmHg, and hexamethonium to 10 +/- 4 mmHg (all P less than 0.01). We conclude that 1) normal LES tone in the cat is mediated primarily by two separate neural mechanisms: a vagal cholinergic mechanism and a nonvagal mechanism that utilizes both alpha-adrenergic and cholinergic receptors; 2) local, intramural mechanisms of high threshold are present in the striated and smooth muscle cat esophagus to allow distension-induced reflex inhibition of the LES; and 3) swallow-induced LES relaxation is dependent on vagally mediated central nervous system connections.

Pancreatitis during sodium valproate treatment

A girl aged 1 year died of acute haemorrhagic pancreatitis while taking sodium valproate. Necropsy showed widespread vascular disease that may have contributed to the onset of pancreatitis. Previous reports of pancreatitis in children receiving valproic acid are reviewed and although the association is rare, a causal relation between pancreatitis and valproic acid seems to have been established.

Effects of a developmental physical activity program on children's body coordination and self-concept

Significant increases in body coordination, little change in self-concept, and moderate negative correlations between these variables were found after 12 children participated in an 8-wk. developmental physical activity program. Apparently, while body coordination might be improved by participation in activity programs of short duration, these improvements may not necessarily be accompanied by increases in self-concept.

ECHINOCOCCUS CYST OF THE OMENTUM

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