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Biomedical subjects

R A Read

Publications and source records attributed to R A Read.

At least 55 records · Page 3Linked to original sources
PubMed1992

Incidence and clinical significance of sesamoid disease in rottweilers.

A group of 55 rottweiler pups was studied from three to 12 months old to assess the incidence and clinical significance of disease involving the palmar metacarpal sesamoid bones. The results of physical examination were correlated with clinical signs of lameness and the results of radiographic examination of the forefeet. Twenty-one dogs became lame during the study and in 12 of them the lameness was attributable to sesamoid disease. However by 12 months of age, the incidence of sesamoid disease as assessed by radiographic changes in the sesamoid bones was 73 per cent (30 of 41 dogs). Six of the 12 dogs which were lame owing to sesamoid disease got better without specific treatment. It was concluded that sesamoid disease can result in clinical lameness in young rottweilers, but that subclinical disease is common.

Age Factors↗
PubMed1992

Postinjury shock and early bacteremia. A lethal combination.

Gut bacteria translocation has been invoked as a prime cause of early postinjury death. To examine this hypothesis, we obtained emergency department blood cultures in 132 acutely injured patients requiring urgent laparotomy for trauma. In the latter half of these patients, mesenteric lymph node and liver biopsy cultures were also performed. The incidence of early bacteremia was 11% (10/94) in the patients without shock compared with 32% (12/38) in the group with shock. The majority (73%) were gram-positive bacteremias. Most notably, Staphylococcus was isolated in 13% (5/38) of the patients with shock, but these isolates were of no apparent clinical significance. In contrast, 18% (7/38) of the patients with shock had enteric bacteremias, and all of these patients died. Cultures were positive in 11% of the liver samples and 15% of the mesenteric lymph nodes. With the exception of two patients with concurrent enteric bacteremias, these hepatic and mesenteric lymph node bacteria were of no clinical significance. In conclusion, bacterial translocation occurs infrequently, and virtually all enteric bacteria were found in dying patients; the cause or effect remains to be defined.

Adult↗
PubMed1992

Efficacy of selective intrabronchial air insufflation in acute lobar collapse.

Flexible fiberoptic bronchoscopy (FFB) to remove mucous plugs followed by selective intrabronchial air insufflation (SII) to expand the atelectatic lung was used in 17 surgical intensive care unit (SICU) patients with pulmonary lobar collapse. Thirteen patients were admitted for acute trauma, and the remainder were elderly postoperative patients. Lobar collapses occurred on SICU days 1 to 18 (mean +/- SEM: 5 +/- 1 days), and duration ranged from 4 to 258 hours (mean: 77 +/- 18 hours). Indications for FFB with SII included critical hypoxemia in 5 patients, worsening collapse in 2, and failure to respond to aggressive respiratory care in 10 (59%). FFB with SII was effective in 14 (82%) patients: 10 achieved full lung re-expansion, and 4 partial lung re-expansion. When lobar collapse was of less than 72 hours' duration, 92% (12 of 13) of patients had lungs re-expanded compared with 50% (2 of 4) whose collapse existed for more than 72 hours. The mean PaO2/FIO2 (fraction inspired oxygen) ratio was 135 +/- 18 prior to FFB with SII and increased to 205 +/- 21 after FFB with SII. Complications were minor and clinically insignificant. In conclusion, SII appears to be a simple, safe, effective adjunct to FFB in the treatment of SICU patients with pulmonary lobar collapse.

Acute Disease↗
PubMed1992

Percutaneous tracheostomy/gastrostomy in brain-injured patients--a minimally invasive alternative.

Tracheostomy and gastrostomy are frequent adjunctive procedures required in the management of patients with severe brain injuries to facilitate neurorehabilitation. We therefore evaluated the use of two minimally invasive surgical procedures, percutaneous tracheostomy (PT) and percutaneous endoscopic gastrostomy (PEG), in 27 patients with severe brain injuries. The mean age was 41 +/- 4 years, and 23 (85%) were men. All patients were intubated, and 19 (70%) required mechanical ventilator support on the day of PT/PEG. The endotracheal tubes had been in place for 1 to 21 days (mean, 8.7 +/- 0.8). All patients were stable from their acute brain injury; 13 had intracranial pressure (ICP) monitors in place. The Seldinger technique, as described by Ciaglia, was employed for PT. Following PT, a PEG was inserted by a modification of the Sachs-Vine "push" technique. We were uniformly successful in placing these access tubes. Complications were minor and not clinically significant. Three of 13 patients (23%) with ICP monitors had a transient rise in ICP related to PT and one of these patients developed local subcutaneous emphysema. Another patient experienced a mild cellulitis at the tracheostomy site. Of note, there were no PEG-related complications. In conclusion, PT and PEG are readily learned, minimally invasive procedures. In our experience with patients with severe brain injuries combined PT/PEG is a uniformly safe alternative to gain long-term access to the airway and gut.

Adolescent↗
PubMed1992

Balloon tamponade for bilobar transfixing hepatic gunshot wounds.

The nonresectional approach to major liver trauma is clearly preferred. Unfortunately, trachotomy with vessel ligation, selective hepatic arterial ligation, perihepatic pack, and fibrin glue are not viable options with high-energy bilobar liver injuries. We have fashioned a balloon tamponade device that has proved very effective for these transfixing hepatic gunshot wounds.

Adolescent↗
PubMed1987

Comparison of synchronized Chinese hamster ovary cells obtained by mitotic shake-off, hydroxyurea, aphidicolin, or methotrexate.

Synchronized cell populations are necessary to study many aspects of cell biology. We have developed a method to obtain highly synchronized Chinese hamster ovary cell populations in S phase or G2 phase by utilizing mitotic selection followed by incubation with either hydroxyurea, aphidicolin, or methotrexate for 12 h. Flow cytometry analysis shows that the coefficient of variation in the spread of the cell population in S phase is as low as 6%. Drug toxicity studies compare the effects of the various drugs on G1 and S phase cells. The use of aphidicolin or hydroxyurea results in the most highly synchronized cell populations, but methotrexate yields inadequate synchronization. These results demonstrate that both aphidicolin and hydroxyurea are useful drugs for obtaining highly synchronized cell populations after an initial synchrony in mitosis. Aphidicolin is perhaps the best choice because of less toxicity to S phase cells when used in low concentrations.

Animals↗
PubMed1985

The cell cycle dependence of thermotolerance. III. HeLa cells heated at 45.0 degrees C.

We have extended our studies on the cell cycle dependence of thermotolerance to include HeLa cells heated at 45.0 degrees C to compare the results to Chinese hamster ovary (CHO) cells. We found that asynchronous HeLa cells were more resistant to heat than CHO cells but showed a similar development and decay of thermotolerance. Flow cytometry (FCM) was used to study redistributions in the cell cycle after an initial heat dose. Cells heated for 35 min at 45.0 degrees C were delayed in G1 by about 7 h compared to controls, with delays in late S and G2/M phase also. The heat sensitivity varied through the cell cycle; G1 cells were the most resistant to heat, while S-phase cells were uniformly sensitive throughout S phase, and G2 cells were resistant. Thermotolerance could be induced and expressed in early or late S-phase cells, but to a lesser extent than for G1 cells. The results were similar in many respects to CHO cells, but there were significant differences.

Acclimatization↗
PubMed1984

The cell cycle dependence of thermotolerance. II. CHO cells heated at 45.0 degrees C.

This report extends our investigations of the cell cycle dependence of the expression of thermotolerance to include tolerance expressed by Chinese hamster ovary (CHO) cells exposed to 45.0 degrees C hyperthermia. We examined the response of asynchronous cells following exposure at 45.0 degrees C. A maximum in thermotolerance under these conditions was reached approximately 12 hr after a 15-min exposure to 45.0 degrees C hyperthermia and progressively decreased thereafter. Cells were delayed in S and G2 phase for 24 hr, after which time cell growth resumed. We then characterized the response of CHO cell populations synchronized in G1 or early or late S phase. We observed that the expression of tolerance depended on the position of cells in the cell cycle and was modulated by changes in the sensitivity of cells as they progressed through the cell cycle subsequent to the tolerance induction dose. We measured the variation in the sensitivity of these cells to 45.0 degrees C hyperthermia throughout the cell cycle and found substantial changes as cells progressed through S phase. Cells in early S phase were the most sensitive to heat at this temperature, and as these cells progressed through S phase, they became progressively more resistant. In addition, G1 cells were delayed for approximately 15 to 18 hr by a 15-min, 45.0 degrees C heat pulse, whereas S-phase cells were delayed to a lesser extent. The data presented in this report suggest that the induction of thermotolerance is relatively non-cell-cycle specific, but the magnitude of expression of tolerance depends on the position of cells in the cell cycle at the time of the subsequent challenge heat dose.

Animals↗
PubMed1983

The cell cycle dependence of thermotolerance. I. CHO cells heated at 42 degrees C.

We examined the dependence of heat killing and thermotolerance on the position and progression of Chinese hamster ovary (CHO) cells in the cell cycle. We measured cell cycle perturbations and survival of asynchronous and synchronized G1-, S-, and G2-phase cells resulting from continuous heating at 42.0 degrees C for up to 80 hr. Thermotolerance under these conditions was transient in nature, was dependent on the position of cells in the cell cycle, and occurred concurrently with a heat-induced delay of progression of G1- and G2-phase cells. When G1 cells were heated, survival decreased to 25% after 4 hr, at which time the thermotolerance was expressed. For G2 cells survival decreased initially at the same rate (T0 congruent to 3 hr) but thermotolerance was not expressed until approximately 12 hr, at which time the survival was 4%. The rate of decrease in survival was much more rapid for cells heated in mid-S phase (T0 congruent to 0.5 hr), and these cells did not express thermotolerance at a measurable level. Concurrent with the expression of thermotolerance, the progression of cells heated in G1 and G2 was delayed. Following the expression of tolerance, progression resumed at a rate approximately equal to the rate of decrease in survival of the G1 population. Cells heated in mid-S phase continued to progress through the cell cycle until they reached G2, where they were also delayed.

Animals↗
PubMed1982

Deformity of the proximal tibia in dogs.

A condition has been recognised in five young dogs in which the proximal tibia exhibited cranial bowing. This altered conformation, sometimes accompanied by bow legs (genu varum), occurs bilaterally, but to differing degrees. The deformity apparently altered the biomechanics of the stifle joint so that degenerative joint disease and rupture of the cranial cruciate ligament followed in four of the five dogs. The aetiology is unknown, but the most likely cause appears to be retardation of growth in the caudal aspect of the proximal tibial physis. Treatment involving surgical techniques to correct the joint instability was only moderately successful.

Animals↗
PubMedDate not supplied

Hiatal hernia controversies--a review of pathophysiology and treatment options.

OBJECTIVE: To provide a detailed discussion of the aetiology and pathophysiology of hiatal hernia in both humans and small animals, and review current medical and surgical treatments. DESIGN: Review article. SUMMARY: Hiatal hernia is not completely understood in humans or animals. It has a complex multifactorial aetiology and pathophysiology. A primary disturbance of the lower oesophageal sphincter has not been shown in humans or animals. Knowledge of pathophysiology is necessary to institute appropriate treatment. Medical and/or surgical therapy is not indicated in asymptomatic cases. Medical treatment should be used for up to 1 month in stable cases of sliding hiatal hernia. Paraoesophageal hiatal hernias and any large sliding hiatal hernia should be considered for prompt surgical treatment. Surgical techniques used depend on the type of hiatal hernia present. Surgical treatment of hiatal hernia cases should be performed by experienced surgeons, and must include hiatal closure and gastropexy. The Nissen fundoplication procedure has been discontinued in the veterinary field due to poor success rates, coupled with the published view that there is a marked difference in pathophysiology between humans and dogs. Reported complications associated with the original Nissen fundoplication technique are identical in the human and veterinary literature. There have been no complications reported with use of the modified or 'floppy' Nissen fundoplication in dogs. Both oesophagopexy and Nissen fundoplication require further evaluation in small animals.

Animals↗