bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebellar cortical abiotrophy in a beagle
Authors: Kent M. , Glass E. , DeLahunta A.
Published: April 2008

A beagle puppy was presented with clinical signs indicative of a cerebellar disease. Histopathological evaluation of the cerebellum revealed a diffuse degenerative cortical lesion. The clinical history and the histopathological findings are consistent with a neonatal cerebellar abiotrophy. Furthermore, the breeding history supports the hypothesis of an inherited genetic disorder that is, most likely, an autosomal recessive trait.
Suspected necrolytic migratory ervthema associated with chronic hepatopathy in a cat
Authors: Godfrey D. R. , Rest J. R.
Published: April 2008

A cat presenting with generalised hypotrichosis and crusts on the feet and tail was found to have an unusual chronic hepatopathy. There was also evidence of a chronic small intestinal disease which went undiagnosed. Necrolytic migratory erythema was suspected based on clinical findings and dermatohistopathology, and an association with the chronic hepatopathy was suggested. This is the first report of such an association in a cat. Serum zinc, amino acids and essential fatty acids were analysed, and medical treatment was given with equivocal efficacy.
Persistent cobalamin deficiency causing failure to thrive in a juvenile beagle
Authors: Fordyce H. H. , Callan M. B. , Giger U.
Published: April 2008

A six‐month‐old beagle was presented with a three‐month history of failure to gain weight, lethargy, intermittent vomiting and seizures. Hypoglycaemia, portosystemic shunt, lead intoxication, gastrointestinal diseases and hereditary metabolic disorders were considered. Laboratory test results of low serum cobalamin (Cbl) concentrations, anaemia, leucopenia and methylmalonic aciduria while the dog was receiving a balanced commercial canine diet were suggestive of a congenital selective Cbl malabsorption. Treatment with repeated injections of parenteral cyanocobalamin (CN‐Cbl) at 50 μg/kg every two weeks corrected the Cbl‐deficient state and reversed all the clinical abnormalities. Selective Cbl malabsorption has previously been described in giant schnauzers and border collies and represents a unique readily treatable hereditary metabolic disorder.
Intestinal haemangiosarcoma in the cat: clinical and pathol Ggical features of four cases
Authors: Sharpe A. , Cannon M. J. , Lucke V. M. , Day M. J.
Published: April 2008

The clinical and pathological features of four cases of feline intestinal haemangiosarcoma are described. All cases were in domestic shorthaired cats and the mean age of the animals (n=3) was 13 years. The tumours originated in the colon, small intestine, ileocaecocolic junction or rectum. The rectal tumour was juxtaposed with an adjacent mast cell neoplasm. Metastasis to mesenteric lymph node occurred in two cases, and in one of these cats there was also abdominal seeding. The histopathological appearance was of a spindle cell neoplasm with vascular differentiation in each case. lmmunohistochemical staining for factor VIII‐related antigen, an endothelial cell marker, confirmed all four tumours to be of endothelial origin. The neoplastic endothelial cells lining irregular vascular channels were more likely to express the antigen than those forming denser sheets without obvious vascular differentiation.
Idiopathic phenobarbital‐responsive hypersialosis in the dog: an unusual form of limbic epilepsy?
Authors: Stonehewer J. , Mackin A. J. , TASKER S. , SIMPSON J. w. , Mayhew I. G.
Published: April 2008

Three unusual cases of salivary gland enlargement and hypersialosis in the dog that responded to anticonvulsant therapy are reported. Presenting complaints included weight loss, hypersalivation, retching and vomiting of several weeks' duration. Two dogs were presented with enlarged painful mandibular salivary glands. The third dog exhibited bizarre behaviour (including jaw chattering) and developed enlarged painful mandibular salivary glands during hospitalisation. Fine needle aspirate cytology and biopsies from the enlarged salivary glands revealed no significant pathological changes. In one dog, an electroencephalogram revealed changes consistent with epilepsy. Hypersialism and salivary gland enlargement resolved completely during phenobarbital administration in all cases. Two dogs were successfully weaned off treatment six months after diagnosis. The remaining dog relapsed after eight months, but normalised with the addition of oral potassium bromide. It is hypothesised that the syndrome Idiopathic hypersialosis may in fact be an unusual form of limbic epilepsy.
Rabbit medicine — gaining some know‐how in the USA
Authors: McNeill Ewan
Published: April 2008

Ewan McNeill, recipient of the 1999 Frank Beattie Trdvel Scholarship, undertook a study trip to the USA, where he divided his time between working at referral centres, visiting first‐opinion general practices, and discussing tuition of rabbit medicine at one of the veterinary colleges. Here he reports on his experiences
Osteopenia and other radiographic signs in canine hyperadrenocorticism
Authors: Schwarz T. , Stork C. K. , Mellor D. , Sullivan M.
Published: April 2008

The specificity of conventional radiography in assessing canine hyperadrenocorticism was evaluated by comparing the incidence of related radiographic findings in 24 hyperadrenocorticoid, 15 diabetic and 20 hypothyroid dogs. Hyperadrenocorticoid dogs showed significantly more perihilar bronchial mineralisation than other groups. There was no significant variation between the disease groups with respect to obesity, hepatomegaly, contour of the caudoventral hepatic margin, peripheral bronchial mineralisation or osteopenia. Adrenal mineralisation and calcinosis cutis were rare findings observed only in hyperadrenocorticoid dogs. The effect of obesity on the radiographic appearance of bone was studied using a dissected lumbar spine from a canine cadaver. An osteopenic effect could be demonstrated by superimposition of a 10 cm‐thick fat block. The low specificity of almost all common signs in canine hyperadrenocorticism and the low incidence of characteristic findings demonstrate the limited potential of radiography in assessing this condition. Radiographic assessment of bone density is unreliable because of artefactual osteopenic effects of high kVp settings necessary in obese dogs.
Hypospadias in a Himalayan cat
Authors: King G. J. , Johnson E. H.
Published: April 2008

A one‐year‐old male Himalayan cat was presented with a history of chronic cystitis. Physical examination revealed that the cat had hypospadias. It was postulated that the abnormal urethral opening on the ventral aspect of the penis permitted faecal contamination of the preputial area and gave rise to the ascending infection. The hypospadias was surgically corrected and a complete recovery was achieved.
Measurement of the back fat layer in beagles for estimation of obesity using two‐dimensional ultrasonography
Authors: Morooka T. , Niiyama M. , Uchida E. , Uemura M. , Miyoshi K. , Saito M.
Published: April 2008

The purpose of this study was to select a suitable location for measuring the subcutaneous fat layer In beagles as an indicator of excess body fat deposition. A location suitable for such a measurement should meet five conditions ‐ it should be easy to: (1) apply the probe, (2) detect the anatomical character of the measurement location, and (3) obtain a reproducible ultrasonogram at all times. In addition, the fat layer should be (4) thick enough for measuring, and (5) located in an area that varies markedly with the degree of obesity. Ultrasonograms made in the transverse planes on the top of the spinous process of the sixth lumbar vertebra, the seventh lumbar vertebra and the first sacral vertebra were found to be suitable for measurement. The depth and area of the back fat layer at these locations were closely related to the degree of obesity.
Bone allografts and adjuvant cisplatin for the treatment of canine appendicular osteosarcoma in 18 dogs
Authors: Morello E. , Buracco P. , Martano M. , Peirone B. , Capurro C. , Valazza A. , Corro D. , Ferracini R. , Sora M.
Published: April 2008

The results achieved in 18 dogs following the use of frozen bone cortical allografts for limb‐sparing resection of non‐metastatic canine appendicular osteosarcoma are presented. Three to five cisplatin doses (70 mg/m2) were administered, starting the day after surgery. The mean and median survival times were 478 and 266 days (range 80 to 2611 days), respectively. The survival rate was 94 per cent at three months, 78 per cent at six months, 35 per cent at 12 months, 23 per cent at 18 months and 19 per cent at 24 months; the disease‐free interval was 80 to 1246 days (mean 365 days, median 266 days). Lung metastasis developed in 55 per cent of the dogs within one year. Complications were observed in 14/18 dogs (78 per cent), comprising local recurrence (28 per cent), allograft infection (39 per cent) and implant failure (11 per cent). Despite complications, limb sparing is a useful alternative to amputation in selected cases of appendicular osteosarcoma.
Cutaneous alternariosis in a cat
Authors: McKay J. S. , Cox C. L. , Foster A. P.
Published: April 2008

A 10‐year‐old male domestic shorthaired cat had a chronic, slowly enlarging subcutaneous mass on the right side of its nose. At the time of presentation, the nasal airflow was severely impeded on the affected side. The cat had been treated medically with various drugs. Oral itraconazole had been the most effective In reducing the size of the mass, but had caused hepatotoxiclty and had to be withdrawn. The mass was finally removed surgically, and a diagnosis of granulomatous cellulitis caused byAlternarla alternata(phaeohyphomycosis) was established, based on histopathology and fungal Isolation. There has been no recurrence of the lesion after 21 months and the cat remains clinically well at the time of writing. Subcutaneous phaeohyphomycosis caused byA altematahas not, to the authors' knowledge, been previously described in small domestic animals in the UK.1
Use of endogenous ACTH concentration and adrenal ultrasonography to distinguish the cause of canine hyperadrenocorticism
Authors: Gould S. M. , Baines E. A. , Mannion P. A. , Evans H. , Herrtage M. E.
Published: April 2008

Twenty‐nine dogs were diagnosed with hyperadrenocorticism (HAC). A single determination of endogenous plasma adrenocorticotropic hormone (ACTH) and adrenal ultrasonography were used in a prospective study to differentiate between pituitary‐dependent HAC (PDH) and adrenal‐dependent HAC (ADH). In 27 out of the 29 dogs (93 per cent), both endogenous plasma ACTH concentrations and adrenal ultrasonography indicated the same cause of HAC. Twenty‐one of the 29 cases (72 per cent) were shown to be pituitary‐dependent; all had plasma ACTH concentrations of greater than 28 pg/ml (reference range 13 to 46 pg/ml) and both adrenal glands were ultrasonographically of similar size and of normal shape. All 21 cases responded well to mitotane therapy. Six cases (21 per cent) were shown to be adrenal‐dependent; all had plasma ACTH concentrations below the limit of the assay (<5 pg/ml) and the presence of an adrenal mass on ultrasonography. The sensitivity and specificity of adrenal ultrasonography and endogenous ACTH determinations to identify the cause of HAC were demonstrated to be 100 per cent and 95 per cent, respectively, for ADH. These discriminatory tests are more accurate than published figures for dexamethasone suppression testing.
Hepatic arteriovenous fistulae and portal vein hypoplasia in a Labrador retriever
Authors: Schaeffer I. G. F. , Kirpensteijn J. , Wolvekamp W. T. C. , Ingh T. S. G. A. M. Van den , Rothuizen J.
Published: April 2008

An 18‐month‐old male Labrador retriever was referred for investigation of chronic intermittent diarrhoea and vomiting of two months duration. A diagnosis of hepatic arteriovenous fistulae was made. These are extremely rare hepatic vascular anomalies which confer arterial pressure to the portal vein. Liver atrophy, portal vein hypoplasia, portal hypertension and multiple acquired portosystemic collateral vessels are the main complications. Surgical excision is a challenge as resection of large lesions may be associated with significant blood loss. In this dog, persistence of portal vein hypoplasia and extensive collateral pathways following surgery led to a reserved prognosis
Lumbosacral osteochondrosis: radiological features and surgical management in 34 dogs
Authors: Hanna F. Y.
Published: April 2008

Lumbosacral osteochondrosis has been diagnosed with increasing frequency over the past few years. Nevertheless, poor recognition of the condition continues to lead to frequent misdiagnosis. A study was therefore undertaken over a 12‐year period (1986 to 1998) to describe the use of a variety of radiological studies to define the syndrome and the use of different surgical techniques for optimal treatment of the condition. Dogs with clinical signs of cauda equina neuropathy and radiological signs of lumbosacral osteochondrosis were older than 14 months (mean age 6‐3 years). German shepherd dogs, boxers and rottweilers were heavily represented. Of the 34 dogs with osteochondrosis in this study, the lesion appeared to be related to the sacrum in 31 dogs (91 per cent) and the seventh lumbar vertebra in the remaining three dogs (9 per cent). Twenty‐seven male and seven female dogs were affected (4:1). Out of the 34 dogs, six (18 per cent) were treated conservatively and the remaining 28 (82 per cent) were treated surgically. The outcome of surgical treatment was considered to be satisfactory in 24 (86 per cent) of these latter dogs.
Malassezia and Candida infections in bull terriers with lethal acrodermatitis
Authors: McEwan N. A.
Published: April 2008

In 12 cases of lethal acrodermatitis (LAD), four sampling techniques (brush, swab, scrape and adhesive tape strip) were used to study the distribution of yeasts in various body sites and these results were compared with those from five cases of atopic dermatitis and those of 10 normal dogs.Malasseziawas frequently isolated from lesional and non‐lesional skin and halrcoat, footpads, nails and mucous membranes from dogs with either LAD or atopic dermatitis, although, generally, moreMalasseziaorganisms were Isolated from LAD cases. In normal dogs,Malasseziawas most frequently recovered from the ear canal and the perianal skin. Candida was isolated frequently from dogs with LAD, but only a single isolate of this yeast was found in the other two groups. Fungal hyphae and pseudohyphae, probably Candida albicans, could be detected In samples collected from the nails and footpads of dogs with LAD. BothMalasseziaand Candida could be isolated using all four sampling techniques. The MacKenzie (toothbrush) technique and adhesive tape strip cultures proved simple methods for the semiquantitative evaluation of yeasts. The high recovery rate ofMalasseziaand Candida from dogs with LAD is probably related to immune dysfunction, particularly T‐cell dysfunction, known to be present in these dogs. C albicans Infection may in part be responsible for the pathogenic changes of the nails and footpads commonly seen in cases of LAD.
Traction alopecia with vasculitis in an Old English sheepdog
Authors: Ordeix L. , Fondevila  , Ferrer L. , Fondati A.
Published: April 2008

A seven‐year‐old entire male Old English sheepdog was presented with a well circumscribed, completely alopecic area on the top of its head, located where a rubber band had been used for several years. A punch biopsy was taken from the centre of the lesion and histological examination revealed cell‐poor, interface mural folliculitis with follicular atrophy and vasculitis. A diagnosis of traction alopecia was made. Oral pentoxyfilline, at 400 mg twice daily, was prescribed for two months, with a slight improvement. To the authors' knowledge, this is the first report of canine traction alopecia accompanied by vascular damage. This vascular damage may represent the pathomechanism of this type of alopecia In the dog.
Urethropexy for the management of urethral sphincter mechanism incompetence in the bitch
Authors: White R. N.
Published: April 2008

Urethropexy was performed on 100 bitches for the management of urethral sphincter mechanism incompetence (SMI). The dogs ranged in age from 12 months to nine years (mean 4–5 years). Diagnosis of the condition was based upon clinical, laboratory and contrast radiographic examinations, and clinical response to medical management. In all bitches, incontinence developed in the adult individual and in the majority (89 bitches) after spaying. Radiographic findings were unremarkable in 22 bitches, apart from the presence of an intrapelvic bladder neck. Follow‐up periods ranged from 12 months to seven years (mean 2–9 years). Fifty‐six bitches were completely cured by surgery, 27 became less incontinent and 17 either failed to respond (nine animals) or showed an initial improvement in urinary function, but then relapsed (eight animals). Nine of these 17 animals underwent a second urethropexy procedure, resulting in a cure in six and an improvement in three cases (follow‐up 12 to 41 months, mean 22‐2 months). A deterioration in the response rate was observed over time. Postoperative complications were seen in 21 bitches and included an increased frequency of micturition (14 bitches), dysuria (six bitches) and anuria (three bitches).
Urethral entrapment following pelvic fracture fixation in a dog
Authors: Messmer M. , Rytz U. , Spreng D.
Published: April 2008

An 18‐month‐old female crossbred dog was presented with a unilateral sacroiliac luxation and separation of the pelvic symphysis. Surgical correction of the luxation with screw fixation led to entrapment of the urethra between the symphyseal parts of the two hemipelves.
Primary ciliary dyskinesia with situs inversus totalis, hydrocephalus internus and cardiac malformations in a dog
Authors: Reichler I. M. , Hoerauf A. , Guscetti F. , Gardelle O. , Stoffel M. H. , Jentsch B. , Walt H. , Arnold S.
Published: April 2008

A nine‐month‐old golden retriever bitch was presented with exercise intolerance and recurrent nasal discharge. Based on clinical, radiographic and ultrasonographic examination, a diagnosis of rhinitis, situs inversus totalis and tricuspid valve insufficiency was established. The results of video‐ and electron microscopy studies of the respiratory epithelium were compatible with primary ciliary dyskinesia (PCD). However, no evidence of a primary ultrastructural defect of the cilia was found. The dog was euthanased because of the poor prognosis. At necropsy, a hydrocephalus internus and a subaortic stenosis were additionally diagnosed. PCD, in combination with situs inversus, has been previously reported in golden retrievers, but without a concomitant hydrocephalus internus. Furthermore, concomitant occurrence of internal cardiac malformation and PCD has not previously been reported in the dog.
Bridging the divide: spinal cord repair by cellular transplantation ‐ from research laboratory to therapeutic application
Authors: JEFFERY N. D. , PENDERIS J. , Smith P. M. , Franklin R. J. M.
Published: April 2008

Spinal cord injury remains a clinical problem for which new therapeutic options are required. Recent developments in spinal cord injury research have suggested that promotion of axonal regeneration by cellular transplantation may be a feasible future treatment modality and it is possible that small animal clinical patients may be the first to benefit from these new approaches. This article describes the experiments which have generated this optimism and considers the steps that will be required to make the transition from laboratory experiments to clinical application.
Effects of medetomidine and buprenorphine administered for sedation in dogs
Authors: Robinson K. J. , Jones R. S. , Cripps P. J.
Published: April 2008

Medetomidine at doses of 10, 20 or 30 μg/kg was administered along with 10 μg/kg buprenorphine intramuscularly to 48 dogs requiring sedation for various diagnostic or therapeutic procedures. The heart rate, respiratory rate and degree of sedation were recorded before and 30 minutes after administration of the drugs. Heart rate fell by a mean of 55 per cent and respiratory rate by a mean of 62 per cent. Mean sedation scores were increased in all groups. Administration of atipamezole at the end of the period of sedation produced rapid recoveries, with a mean time to standing of 12 minutes. Animals that were anaesthetised required much less thiopentone than the 10 mg/kg recommended after premedication with acepromazine maleate.
Multilobular tumour of bone with no abnormalities on plain radiography in a dog
Authors: Stoll M. R. , Roush J. K. , Moisan P. G.
Published: April 2008

A seven‐year‐old neutered female golden retriever was presented for an acute onset of cervical pain and ataxia. Intervertebral disc disease or neoplasia was suspected. There was no evidence of a soft tissue or bony mass on physical examination or survey radiographs. Cerebrospinal fluid analysis did not show any evidence of a neoplastic process. Myelography evaluation identified an extradural mass lesion extending from inside the calvarium to the mid‐body of the first cervical vertebra. No additional diagnostic tests were performed as the owners elected for euthanasia because of the high possibility of a neoplastic process with an accompanying poor prognosis. Multilobular tumour of bone was diagnosed on postmortem examination.
An Overview of Lexical Phonology
Authors: Rubach Jerzy
Published: April 2008

This article reviews Lexical Phonology, a theory of rules and derivations. Rules are of three types: cyclic rules, postcyclic rules, and postlexical rules. Various diagnostic properties of rules are discussed, including the phonological cycle, word vs. phrase domain application, the Strict Cyclicity Constraint, derived environments, the Structure Preservation Constraint, lexical conditioning, and the interaction of phonology and morphology. The data are drawn from English, Dutch, Polish, Russian, and Slovak.
Thermal Recovery of Iodopsin from Photobleaching Intermediates†
Authors: Imamoto Yasushi , Shichida Yoshinori
Published: April 2008

The chloride effect on the photobleaching process of iodopsin, a chicken red‐sensitive cone visual pigment, was studied in detail by time‐resolved low‐temperature spectroscopy at −40°C to −10°C. Decay‐associated difference spectra obtained by kinetic analysis using the singular value decomposition method were composed of spectra of BL‐iodopsin, lumiiodopsin, metaiodopsin I, metaiodopsin II and metaiodopsin III, essentially identical to those at room temperature. In each conversion step however, iodopsin was partially regenerated, which is not observed in the bleaching process for other visual pigments or iodopsin at room temperature. Moreover, iodopsin was slowly regenerated from the bleached species. The reverse reactions were completely suppressed by substitution of lyotropic NO3− for Cl−, suggesting that Cl− binding to iodopsin interferes with light‐induced cis–trans isomerization of the chromophore. It is likely that the water molecule hydrating Cl− forms the additional hydrogen bond(s), by which the protein conformational change necessary to release this steric hindrance becomes enthalpic. As progress of the bleaching process is a consequence of protein conformational change, it is suppressed at low temperatures, resulting in thermal back‐isomerization.
Low‐temperature Spectroscopy of Met100Ala Mutant of Photoactive Yellow Protein†‡
Authors: Imamoto Yasushi , Harigai Miki , Morimoto Takashi , Kataoka Mikio
Published: April 2008

The trans‐to‐cis photoisomerization of the p‐coumaroyl chromophore of photoactive yellow protein (PYP) triggers the photocycle. Met100, which is located in the vicinity of the chromophore, is a key residue for the cis‐to‐trans back‐isomerization of the chromophore, which is a rate‐determining reaction of the PYP photocycle. Here we characterized the photocycle of the Met100Ala mutant of PYP (M100A) by low temperature UV–visible spectroscopy. Irradiation of M100A at 80 K yielded a 380 nm species (M100ABL), while the corresponding intermediate of wild type (WT; PYPBL) is formed above 90 K. The amounts of redshifted intermediates produced from M100A (M100AB′ and M100AL) were substantially less than those from WT. While the near‐UV intermediate (PYPM) is not formed from WT in glycerol samples at low temperature, M100AM was clearly observed above 190 K. These alterations of the photocycle of M100A were explained by the shift in the equilibrium between the intermediates. The carbonyl oxygen of the thioester linkage of the cis‐chromophore in the photocycle intermediates is close to the phenyl ring of Phe96 (<3.5 Å), which would be displaced by the mutation of Met100. These findings imply that the interaction between chromophore and amino acid residues near Met100 is altered during the early stage of the PYP photocycle.
Chromophore Interaction in Xanthorhodopsin—Retinal Dependence of Salinixanthin Binding†
Authors: Imasheva Eleonora S. , Balashov Sergei P. , Wang Jennifer M. , Smolensky Elena , Sheves Mordechai , Lanyi Janos K.
Published: April 2008

Xanthorhodopsin is a light‐driven proton pump in the extremely halophilic bacterium Salinibacter ruber. Its unique feature is that besides retinal it has a carotenoid, salinixanthin, with a light harvesting function. Tight and specific binding of the carotenoid antenna is controlled by binding of the retinal. Addition of all‐trans retinal to xanthorhodopsin bleached with hydroxylamine restores not only the retinal chromophore absorption band, but causes sharpening of the salinixanthin bands reflecting its rigid binding by the protein. In this report we examine the correlation of the changes in the two chromophores during bleaching and reconstitution with native all‐trans retinal, artificial retinal analogs and retinol. Bleaching and reconstitution both appear to be multistage processes. The carotenoid absorption changes during bleaching occurred not only upon hydrolysis of the Schiff base but continued while the retinal was leaving its binding site. In the case of reconstitution, the 13‐desmethyl analog formed the protonated Schiff base slower than retinal, and provided the opportunity to observe changes in carotenoid binding at various stages. The characteristic sharpening of the carotenoid bands, indicative of its reduced conformational heterogeneity in the binding site, occurs when the retinal occupies the binding site but the covalent bond to Lys‐240 via a Schiff base is not yet formed. This is confirmed by the results for retinol reconstitution, where the Schiff base does not form but the carotenoid exhibits its characteristic spectral change from the binding.
Rhodopsin Regeneration is Accelerated via Noncovalent 11‐cis Retinal–Opsin Complex—A Role of Retinal Binding Pocket of Opsin†
Authors: Matsumoto Hiroyuki , Yoshizawa Tôru
Published: April 2008

The regeneration of bovine rhodopsin from its apoprotein opsin and the prosthetic group 11‐cis retinal involves the formation of a retinylidene Schiff base with the ε‐amino group of the active lysine residue of opsin. The pH dependence of a Schiff base formation in solution follows a typical bell‐shaped profile because of the pH dependence of the formation and the following dehydration of a 1‐aminoethanol intermediate. Unexpectedly, however, we find that the formation of rhodopsin from 11‐cis retinal and opsin does not depend on pH over a wide pH range. These results are interpreted by the Matsumoto and Yoshizawa (Nature258 [1975] 523) model of rhodopsin regeneration in which the 11‐cis retinal chromophore binds first to opsin through the β‐ionone ring, followed by the slow formation of the retinylidene Schiff base in a restricted space. We find the second‐order rate constant of the rhodopsin formation is 6100 ± 300 mol−1 s−1 at 25°C over the pH range 5–10. The second‐order rate constant is much greater than that of a model Schiff base in solution by a factor of more than 107. A previous report by Pajares and Rando (J Biol Chem264 [1989] 6804) suggests that the lysyl ε‐NH2 group of opsin is protonated when the β‐ionone ring binding site is unoccupied. The acceleration of the Schiff base formation in rhodopsin is explained by stabilization of the deprotonated form of the lysyl ε‐NH2 group which might be induced when the β‐ionone ring binding site is occupied through the noncovalent binding of 11‐cis retinal to opsin at the initial stage of rhodopsin regeneration, followed by the proximity and orientation effect rendered by the formation of noncovalent 11‐cis retinal–opsin complex.
Lewis‐acid‐catalyzed Photodimerization of Coumarins and N‐methyl‐2‐quinolone
Authors: Görner Helmut , Wolff Thomas
Published: April 2008

The BF3‐catalyzed photodimerization of parent coumarin (1), three 6‐alkylcoumarins (2–4) and N‐methyl‐2‐quinolone (5) in dichloromethane was studied by time‐resolved UV–vis spectroscopy. The lowest triplet state properties in the absence and presence of BF3 were outlined, in particular the effect of self‐quenching which initiates dimerization. The quantum yield of intersystem crossing (Φisc) of 1–4 increases with BF3 concentration, approaching Φisc = 0.3. Φisc and the relative quantum yield of dimerization go along, thereby favoring an overall triplet mechanism in both the direct and BF3‐catalyzed photodimerization. The product ratio of 5 changes strongly with the BF3 concentration from 100%anti‐hh for the free quinolone to 100%syn‐ht for the 1:1 complex.
Vascular System: Role of Nitric Oxide in Cardiovascular Diseases
Authors: Bian Ka , Doursout Marie‐Françoise , Murad Ferid
Published: April 2008

In contrast with the short research history of the enzymatic synthesis of nitric oxide (NO), the introduction of nitrate‐containing compounds for medicinal purposes marked its 150th anniversary in 1997. Glyceryl trinitrate (nitroglycerin) is the first compound of this category. On October 12, 1998, the Nobel Assembly awarded the Nobel Prize in Medicine or Physiology to scientists Robert Furchgott, Louis Ignarro, and Ferid Murad for their discoveries concerning NO as a signaling molecule in the cardiovascular system. NO‐mediated signaling is a recognized component in various physiologic processes (eg, smooth muscle relaxation, inhibition of platelet and leukocyte aggregation, attenuation of vascular smooth muscle cell proliferation, neurotransmission, and immune defense), to name only a few. NO has also been implicated in the pathology of many inflammatory diseases, including arthritis, myocarditis, colitis, and nephritis and a large number of pathologic conditions such as amyotrophic lateral sclerosis, cancer, diabetes, and neurodegenerative diseases. Some of these processes (eg, smooth muscle relaxation, platelet aggregation, and neurotransmission) require only a brief production of NO at low nanomolar concentrations and are dependent on the recruitment of cyclic guanosine monophosphate (cGMP)‐dependent signaling. Other processes are associated with direct interaction of NO or reactive nitrogen species derived from it with target proteins and requires a more sustained production of NO at higher concentrations but do not involve the cGMP pathway.
Can Ischemic Stroke Be Caused by Acute Reduction of Blood Pressure in the Acute Phase of Cardiovascular Disease?
Authors: Hoshide Satoshi , Eguchi Kazuo , Ishikawa Joji , Murata Mitsunobu , Katsuki Takaaki , Mitsuhashi Takeshi , Shimada Kazuyuki , Kario Kazuomi
Published: April 2008

Acute‐phase cardiovascular disease (CVD) frequently presents with markedly elevated blood pressure (BP) levels and often requires fairly rapid lowering of BP. On the other hand, aggressive lowering of systemic BP to the point that the cerebral BP decreases below a certain threshold may result in ischemic stroke. The authors retrospectively studied 192 consecutive patients with CVD who had markedly elevated BP and end‐organ damage. Ischemic stroke was noted in 12 of these patients during BP‐lowering therapy. The incidence of ischemic stroke did not differ significantly between a standard BP‐lowering group, in which the target BP reduction was within the parameters of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure guidelines, and a rapid BP‐lowering group, in which the target BP was below these guidelines (7.1% vs 2.6%, respectively; P=.27, not significant). In stepwise multiple regression analysis, diabetes mellitus (β=0.203, P=.008) and acute pulmonary edema (β=0.228, P=.003) remained significant factors associated with the incidence of stroke. Thus, acute pulmonary edema and diabetes were the most important factors related to ischemic stroke during BP reduction in patients with marked elevations of BP regardless of the rapidity of BP lowering.
Implementing Effective Hypertension Quality Improvement Strategies: Barriers and Potential Solutions
Authors: Walsh Judith M. E. , Sundaram Vandana , McDonald Kathryn , Owens Douglas K. , Goldstein Mary Kane
Published: April 2008

Many quality improvement strategies have focused on improving blood pressure control, and these strategies can target the patient, the provider, and/or the system. Strategies that seem to have the biggest effect on blood pressure outcomes are team change, patient education, facilitated relay of clinical information, and promotion of self‐management. Barriers to effective blood pressure control can affect the patient, the physician, the system, and/or “cues to action.”We review the barriers to achieving blood pressure control and describe current and potential creative strategies for optimizing blood pressure control. These include home‐based disease management, combined patient and provider education, and automatic decision support systems. Future research must address which components of quality improvement interventions are most successful in achieving blood pressure control.
Prevention of Cardiovascular Events by Treating Hypertension in Older Adults: An Evidence‐Based Approach
Authors: Firdaus Muhammad , Sivaram Chittur A , Reynolds Dwight W.
Published: April 2008

Hypertension in older adults is not well controlled in clinical practice. Isolated systolic hypertension is often more difficult to manage. A systematic PubMed search was conducted to look for evidence showing benefits of lowering blood pressure (BP) in older hypertensive adults. Lowering BP in these individuals significantly reduces the risk of coronary artery disease, stroke, and cardiovascular and all‐cause mortality. Based on trial evidence, a low‐dose diuretic should be considered the most appropriate first‐step treatment for preventing cardiovascular morbidity and mortality. Therapy with >1 medication is often necessary to reduce BP in these patients. There is unequivocal evidence that cardiovascular events can be prevented in older adults, even those older than 80 years, by treating hypertension.
Use of Home Blood Pressure Monitoring by Hypertensive Patients in Primary Care: Survey of a Practice‐Based Research Network Cohort
Authors: Viera Anthony J. , Cohen Lauren W. , Mitchell C. Madeline , Sloane Philip D.
Published: April 2008

Using a survey of a cohort of primary care patients, the authors determined the proportion currently using home blood pressure monitoring (HBPM) and calculated odds ratios (ORs) of factors associated with such use. Overall, 530 questionnaires were received (80% response rate); 35.2% of respondents reported that their doctor had recommended HBPM (95% confidence interval [CI], 31.1–39.3), and 43.1% reported currently using HBPM (95% CI, 38.8–47.3). Compared with patients younger than 45 years, hypertensive patients older than 65 years were more likely to be using HBPM (OR, 2.53; 95% CI, 1.20–5.33). Those with a history of stroke/transient ischemic attack were also more likely to use HBPM (OR, 2.06; 95% CI, 1.00–4.24). Compared with patients with a level of hypertension knowledge <10th percentile, those with a knowledge level >90th percentile were more likely to use HBPM (OR, 1.96; 95% CI, 1.08–3.56). The factor most strongly associated with use of HBPM was recalling a doctor's recommendation to do so (OR, 7.93; 95% CI, 4.96–12.7).
Boiling Heat Transfer Rates for Small Precisely Placed Water Droplets on a Heated Horizontal Plate
Authors: Sellers Sally M. , Black W. Z.
Published: April 2008

Two small horizontal surfaces, heated to temperatures up to 220°C, were cooled by small (50–300 mm diameter) room-temperature droplets at 1 atmosphere pressure. One surface was a 10×10 mm thin-film nichrome heater that was used to measure heat fluxes below 100 W/cm2. The other surface, used for fluxes in excess of 100 W/cm2, was a solid copper heater with an 8×8 mm exposed surface. A continuous jet droplet generator coupled with two mutually perpendicular deflection plates was used to manipulate the path of constant diameter water droplets so that the impact of the drops could be precisely located on the heated surfaces. The droplet generator and the deflection plates were employed so that the effect of the impact frequency, droplet diameter, droplet velocity and spacing on the resulting heat transfer rates could be studied under controlled conditions. Optimal droplet spacing between 0.75 and 1.5 times the droplet diameter increased the critical heat flux approximately 30 percent above the value that was achieved when the drops were deposited in one location. For area-averaged mass flow rates less than about 0.08 g/(cm2s), there was no trend in the critical heat flux with the Weber number. However, for larger mass flux rates, the critical heat flux increased with an increasing Weber number. The measured critical heat flux values were roughly twice the heat flux of traditional pool boiling for identical superheat temperatures. Two droplet cooling dimensionless critical heat flux correlations are proposed as a function of Weber and Strouhal numbers; one for a single stream of drops and the other for drops that are spaced across the heated surface. The correlation for the spaced droplets is a function of a dimensionless droplet spacing on the heater.
Proposed Modification to Whole Domain Function Specification Method to Improve Accuracy of Its Estimations
Authors: Chen Cha’o-Kuang , Wu Li-Wen , Yang Yue-Tzu
Published: April 2008

This paper investigates the inverse heat transfer problem of laminar forced convection within a circular pipe. The performances of two classical algorithms used in the whole domain function specification method (WDFSM) to obtain simultaneous estimates of the time-varying inlet temperature and outer-wall heat flux are compared. Additionally, this study proposes a modification to the linear assumption employed in the conventional WDFSM to improve its estimation performance. The WDFSM solution procedure is based on future temperature measurements at two different locations within the pipe flow. In the modified algorithm, the variations of the estimations at all time steps for various values of the future-time parameter are investigated, and if large variations in the slope of the function are detected at some time steps, the originally linear assumption for the variation of the unknowns is replaced with the assumption of a constant function at these time steps. Otherwise, the estimates at the other time steps are calculated using the linear assumption. The numerical results confirm that the proposed algorithm yields slightly more accurate estimates of the unknowns than the two classic algorithms.
Natural Convection Heat Transfer in a Partially Open Square Cavity With a Thin Fin Attached to the Hot Wall
Authors: Ben-Nakhi Abdullatif , Eftekhari M. M. , Loveday D. I.
Published: April 2008

A computational study of steady, laminar, natural convective fluid flow in a partially open square enclosure with a highly conductive thin fin of arbitrary length attached to the hot wall at various levels is considered. The horizontal walls and the partially open vertical wall are adiabatic while the vertical wall facing the partial opening is isothermally hot. The current work investigates the flow modification due to the (a) attachment of a highly conductive thin fin of length equal to 20%, 35%, or 50% of the enclosure width, attached to the hot wall at different heights, and (b) variation of the size and height of the aperture located on the vertical wall facing the hot wall. Furthermore, the study examines the impact of Rayleigh number (104⩽Ra⩽107) and inclination of the enclosure. The problem is put into dimensionless formulation and solved numerically by means of the finite-volume method. The results show that the presence of the fin has counteracting effects on flow and temperature fields. These effects are dependent, in a complex way, on the fin level and length, aperture altitude and size, cavity inclination angle, and Rayleigh number. In general, Nusselt number is directly related to aperture altitude and size. However, after reaching a peak Nusselt number, Nusselt number may decrease slightly if the aperture’s size increases further. The impact of aperture altitude diminishes for large aperture sizes because the geometrical differences decrease. Furthermore, a longer fin causes higher rate of heat transfer to the fluid, although the equivalent finless cavity may have higher heat transfer rate. In general, the volumetric flow rate and the rate of heat loss from the hot surfaces are interrelated and are increasing functions of Rayleigh number. The relationship between Nusselt number and the inclination angle is nonlinear.
Combined Effect of Temperature Modulation and Magnetic Field on the Onset of Convection in an Electrically Conducting-Fluid-Saturated Porous Medium
Authors: Bhadauria B. S.
Published: April 2008

The effect of temperature modulation on the onset of thermal convection in an electrically conducting fluid-saturated-porous medium, heated from below, has been studied using linear stability analysis. The amplitudes of temperature modulation at the lower and upper surfaces are considered to be very small. The porous medium is confined between two horizontal walls and subjected to a vertical magnetic field; flow in porous medium is characterized by Brinkman–Darcy model. Considering only infinitesimal disturbances, and using perturbation procedure, the combined effect of temperature modulation and vertical magnetic field on thermal instability has been studied. The correction in the critical Rayleigh number is calculated as a function of frequency of modulation, Darcy number, Darcy Chandrasekhar number, magnetic Prandtl number, and the nondimensional group number χ. The influence of the magnetic field is found to be stabilizing. Furthermore, it is also found that the onset of convection can be advanced or delayed by proper tuning of the frequency of modulation. The results of the present model have been compared with that of Darcy model.
Do You Prefer to Have the Text or a Sheet with Your Physics Exams?
Authors: Hamed Kastro M.
Published: April 2008

Many high school and introductory college physics instructors ponder the choice between “open text” exams versus “facts and formulae sheet” exams. Other alternatives are closed book/closed notes exams or an instructor-prepared sheet of facts and relevant formulas. There is no agreement on merit. Rehfuss1 strongly opposes allowing students to use formula sheets while taking physics exams despite acknowledging that such use is common practice. Cone2 responded to Rehfuss by defending the use of such sheets and outlining the benefits of a “cheat sheet.” Debate over the use of a “cheat sheet” or other resources during exams is not limited to the physics community. Skidmore and Aagaard3 studied the relationship between testing conditions and student test scores for students in teacher education. Two decades earlier Boniface,4 Dorsal and Cundiff,5 and Hindman6 published papers on the use of texts and/or sheets during examinations in psychology and education. Others, such as Pullen et al.7 focused on studying the discarded cheat sheets themselves. Humorously, in October 2005 The New York Times8 reported an unusual museum exhibit of “cheat sheets” and the different ways students had cheated at a particular university.
Galileo's Paradox
Authors: Greenslade Thomas B.
Published: April 2008

The paradox is a wonderful teaching tool. The sleepy student in the back row is surprised and wakes up, and the student with the instantly memorized answer is forced into the analytical mode. The diagram in Fig. 1 has the following paradox: A body sliding freely down a chord from the edge of the circle reaches the lowest point on the circle at the same time as a body released simultaneously from the top. This result was first mentioned in a 1602 letter from Galileo Galilei to Guidobaldo dal Monte.1
Promoting Science via an Equipment Loan Outreach Program
Authors: Krieble Kelly , Salter Carl
Published: April 2008

An important component of many college and university science programs is that of community outreach. Some of the more typical kinds of outreach activities include teacher training workshops, public lectures, open house “science days,” and school demonstration visits. The latter activity usually consists of students and faculty transporting equipment from their institution to a local secondary school to provide “hands-on” demonstrations or activities to a few science classes. One problem with such visits is the short interaction time (usually an hour or so), which often comes and goes and is soon forgotten by the participating students. We discuss in this paper the specifics of an outreach program that has been successful in addressing this and other issues.
Ballistocardiography in the Physics Classroom
Authors: Paul Prabasaj , Symes Laurel B.
Published: April 2008

Ballistocardiograms (BCGs) are graphical representations of the recoil from the pumping action of the heart. Introductory mechanics and a basic knowledge of the circulatory system are sufficient to understand the key features of a BCG. BCGs with adequate detail for instructional purposes may be produced easily and rapidly using hardware (a force plate) and software common to introductory physics labs. The interdisciplinary nature of this exercise is a particularly attractive feature. We have used it as a demonstration in a course on mechanics for nonphysics majors as well as for visiting high school students, and indicate here possible ways to incorporate it into upper-level physics or biomechanics courses.
Megapixels and Human Recognition of Resolution
Authors: Kreis Steve
Published: April 2008

This paper tries to demonstrate that it is not reasonable to judge the quality of pictures that a camera can produce just by the number of pixels that the sensor has. It does so by trying to relate the number of pixels in a picture to the resolution that the eye can see at various distances away from prints of different size.
First Steps Toward Increasing Student Engagement During Lecture
Authors: Slater Timothy F.
Published: April 2008

Have you tried to repurpose materials you've gotten from another lecturer or publisher that you thought could express a concept exceptionally well, only to find when you used the same materials, they did not have the dramatic effect on your students you desired? It would be easy to conclude that student apathy is to blame. But, if students listening to your lecture take on the same bored appearance and passive disposition often observed when you are showing a video, consider whether your instructional approach is designed to intellectually engage students. An information-download lecture has often been described as…the process by which the teacher's notes get transferred into students' notebooks without passing through the brains of either. That brilliant set of lecture materials that you thought would be perfect might need to be adjusted to meet the learning styles of your students to actively engage them in developing conceptual understanding.