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Biomedical subjects

D Holt

Publications and source records attributed to D Holt.

90 records · Page 5Linked to original sources
PubMed1981

Quantitative two dimensional echocardiography during bicycle exercise in normal subjects.

A quantitative two dimensional echocardiographic study was conducted in 10 normal subjects performing bicycle exercise in a supine position. Standardized two dimensional echocardiographic short axis and apical views of the left ventricle were analyzed to derive left ventricular sectional areas and length. Over a range of exercise heart rates from 108 to 152 beats/min, satisfactory two dimensional echocardiographic views and measurements were obtained for quantitative assessment of sectional and global left ventricular function. Variability of left ventricular short axis area measurements ranged from 2.9 to 8.3 percent. Left ventricular volume reconstruction employed a simplified formula (volume = 5/6 area X length) with a single papillary muscle level short axis area and left ventricular length. Changes in left ventricular function from rest to exercise quantitated by two dimensional echocardiography indicated a significant reduction in end-systolic volume (from 28.1 +/- 5.6 to 20.8 +/- 4.3 cc/m2, p less than 0.001) and increased left ventricular ejection fraction (from 63.4 +/- 6.3 to 72.1 +/- 5.7 percent, p less than 0.001). The change in end-diastolic volume was not significant. It is concluded that standardized two dimensional echocardiographic study during supine bicycle exercise in normal subjects provides good reproducibility of measurement of sectional and global left ventricular function. Quantitative two dimensional echocardiographic exercise study of global as well as segmental left ventricular performance in patients may be feasible using standardized procedure and analysis.

Adolescent↗
PubMed1980

The interaction of cadium-induced rat renal metallothionein with bivalent mercury in vitro.

Addition of Hg2+ in vitro to metallothionein (Cd : Cu : Zn = 6.5 : 4 : 1) from the kidneys of Cd2+ exposed rats appears to result initially in the replacement of Zn2+, then Cd2+ and finally copper. The ionic stoichiometries between Hg2+-binding and the release of Cd2+ (or Zn2+) and copper are 3 : 2 and 1 : 1 respectively. After treatment with amounts of Hg2+ sufficient to displace completely either the bound Zn2+ and Cd2+, or all of the original cations, the metallothionein has little or no negative charge at pH 8.0 and is not resolved into the two isometallothioneins, which characterize the (Cd, Cu, Zn)-thionein, by ion exchange chromatography at this pH. Cation substitution occurs in both isometallothioneins and there is no evidence that Hg2+ interacts preferentially with one of them. Treatment of the metallothionein with increasing amounts of Hg2+, equivalent to approx. 25% and 50% of the bound cations gives rise to a range of molecular species of progressively decreasing negative charge. The consistent stiochiometry between Hg2+ uptake and Cd2+ or Zn2+ release at all concentrations of Hg2+ indicates that free thiol groups are not formed during the substitution reaction.

Animals↗
PubMed1980

The in vivo effects of maleate on the cation-distribution in rat kidney metallothionein sub-fractions after induction by cadmium and/or mercury.

The metallothionein fractions, isolated by gel filtration from the kidneys of rats that have been dosed with Cd2+, Hg2+ or Cd2+ followed by Hg2+, yield very different elution profiles on ion-exchange chromatography. The metallothionein from Cd2+-treated animals is resolved into the isomethallothioneins I and II and a minor, less negatively-charged species (B), which contains Cd2+ and copper, but little Zn2+. The corresponding fraction from the kidneys of rats doses with Hg2+ yields five components, all of which contain Hg2+, Zn2+ and Cu, but in different ratios. Three of these compounds correspond in their elution characteristics from DE-cellulose with the above-mentioned isometallothioneins I and II and fraction B. The last of these, which also is rich in Cu, is the major Hg2+-binding component. The distribution of Hg2+ and of other cations between these five sub-fractions, but not the number of sub-fractions, is altered by Cd2+-pretreatment of the animals. Treatment of Cd2+-dosed rats with sodium maleate has no significant effect on the distribution of cations (Cd2+, Zn2+ and copper) amongst the renal metallothionein subfractions. The same treatment, applied to animals dosed with either Hg2+ only, or Cd2+ followed by Hg2+, causes the elimination of 70--75% of the Hg2+ from the metallothionein fraction. Loss occurs from all subfractions, but is greatest in subfraction B, which also loses copper. Whilst it is possible that Hg2+ may induce metallothionein and other metalloproteins in the kidney, Hg2+ appears to bind to both isometallothioneins I and II, when these are induced by Cd2+-pretreatment. The loss of Hg2+, but not of Cd2+, from these metalloproteins after treatment with sodium maleate may be related to differences in the relative binding affinities of the two cations for thionein and other cellular proteins.

Animals↗
PubMedDate not supplied

Esophageal obstruction caused by a left aortic arch and an anomalous right patent ductus arteriosus in two German Shepherd littermates.

OBJECTIVE: To present details of surgical management of an unusual vascular ring anomaly in two German Shepherd littermates. STUDY DESIGN: Clinical case report. STUDY POPULATION: Three-month-old intact male and female German Shepherd littermates. RESULTS: In each dog, the esophagus was obstructed by a vascular ring comprised of the left aortic arch, an anomalous patent right ductus arteriosus, and the pulmonary artery ventrally. Surgical treatment consisted of dividing and oversewing the patent right ductus arteriosus. Neither dog has clinical signs of esophageal disease one year after treatment. CONCLUSION AND CLINICAL RELEVANCE: This vascular ring anomaly should be considered a possibility in any young dog with esophageal obstruction and a machinery murmur.

Animals↗
PubMedDate not supplied

Excision of tumors in the nasal vestibule of two dogs.

Two dogs with tumors in the left nasal vestibule were treated by surgical excision of the affected part of the nose. Radiation and chemopotentiation were used in one dog, which remained tumor-free after 12 months. When recovering from anesthesia, the second dog developed respiratory distress associated with upper airway obstruction and failure to mouth breathe. The dog was successfully treated by temporary tracheostomy and remained tumor-free after 3 months. Surgery preserved the function of the right nostril and gave an acceptable cosmetic result in both cases.

Airway Obstruction↗
PubMedDate not supplied

Colopexy as a treatment for rectal prolapse in dogs and cats: a retrospective study of 14 cases.

Colopexy was evaluated as a treatment for recurrent rectal prolapse in eight dogs and six cats. Cases included in the study were from two institutions; the University of Pennsylvania School of Veterinary Medicine and the University of Tennessee College of Veterinary Medicine. Two different colopexy techniques were used: A simple suture technique was used in two cats and four dogs (University of Pennsylvania), and an incisional technique was used in four cats and four dogs (University of Tennessee). Rectal prolapse had not recurred in any of the 14 animals at the time of follow-up. Incisional dehiscence occurred in two animals and in one instance may have been related to the colopexy procedure. Infection at the colopexy site, secondary to suture penetration of the colonic lumen, is a potential complication of this procedure. Colopexy, using either surgical technique described here, was effective in preventing recurrent rectal prolapse.

Animals↗
PubMedDate not supplied

Caudal vena cava obstruction and ascites in a cat treated by balloon dilation and endovascular stent placement.

OBJECTIVE: To present details of an unusual case of caudal vena caval obstruction and its management in a cat. STUDY DESIGN: Clinical case report. STUDY POPULATION: A 15 month old male castrated domestic shorthaired cat. RESULTS: The diagnostic evaluation included the use of digital subtraction angiography and ultrasonography to locate the caudal vena caval obstruction. Treatment initially involved puncture and balloon dilation of the obstructed area of the cava. After reobstruction, the stenotic area was redilated and stented. The cat was euthanatized 4 weeks later because of vomiting, anorexia, and abnormal behavior, presumed to be associated with liver disease. CONCLUSION AND CLINICAL RELEVANCE: Interventional radiography provided a minimally invasive way to manage this unusual vascular anomaly.

Angiography↗
PubMedDate not supplied

Congenital esophageal hiatal hernia in the Chinese shar-pei dog.

Esophageal hiatal hernia was diagnosed in 11 young Chinese Shar-Pei dogs between October 1985 and July 1991. The dogs ranged in age from 2 to 11 months and included 3 females and 8 males. The most common clinical signs were regurgitation, vomiting, and hypersalivation. Physical examination was normal in 6 dogs; abnormal physical examination findings in the other 5 dogs included fever, dehydration, hypersalivation, and pulmonary wheezes and crackles. Laboratory evaluation was significant only for neutrophilia in 5 dogs. A diagnosis of hiatal hernia was made on the basis of survey thoracic radiographic and/or barium esophagram findings of displacement of the esophagogastric junction and stomach into the thoracic cavity; the diagnosis was confirmed by surgery in 9 dogs and at necropsy in 2 dogs. Megaesophagus (n = 7), gastroesophageal reflux (n = 4), and esophageal hypomotility (n = 1) were additional findings in some dogs. Aspiration pneumonia was diagnosed in 7 of the dogs. Medical therapies formulated for the therapy of presumed reflux esophagitis generally failed to resolve the clinical signs associated with the hiatal hernia. Hiatal herniae were surgically repaired in 9 of the Shar-Peis by various combinations of diaphragmatic crural apposition, fixation of the esophagus to the diaphragmatic crus (esophagopexy), and left fundic tube gastropexy. Eight of the animals survived surgery, six of which have been asymptomatic since surgery (19 to 36 months). The megaesophagus, esophageal hypomotility, and bronchopneumonia resolved in all of these dogs.

Administration, Oral↗
PubMedDate not supplied

Lateral exploration of fistulas developing after total ear canal ablations: 10 cases (1989-1993).

A lateral approach was used successfully in seven of 10 dogs to resolve fistulas which developed after total ear canal ablations and bulla osteotomies. The approach facilitated identification and removal of horizontal ear canal remnants in four of the 10 cases. Facial nerve function was worsened temporarily by lateral exploration in two cases. Seven cases had no fistula recurrence during follow-up, which ranged from 12 to 72 months. Three cases each had fistula recurrence one-to-two months after fistula exploration.

Animals↗
PubMedDate not supplied

Liver transplantation: who to refer and when.

Liver transplantation is a surgical procedure offered to individuals with irreversible, near fatal liver disease. The timing of both transplantation listing and surgical engraftment are critical factors in the success of this endeavour. To accomplish each and maintain surgical survival rates without prematurely transplanting individuals to achieve excellent outcome statistics is an art that requires knowledge about the procedure and the natural history of the specific liver disease in question. Herein are the views of the transplant team at Loyola University of Chicago as to how this can be accomplished within the framework of the American experience, and the rules and regulations governing donor organ procurement and allocation in the United States.

Costs and Cost Analysis↗
PubMedDate not supplied

Women and HIV: when to test?

The devastating effects of HIV infection in women can be altered dramatically with new therapies. Certain clinical syndromes, including oral thrush, diffuse lymphadenopathy, wasting, unexplained fevers, or oral hairy leukoplakia, clearly indicate a need for HIV testing. This article reviews other clinical syndromes, both gender-specific and non-gender-specific, that may prompt the practitioner to consider HIV testing.

Adult↗