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Biomedical subjects

J M Chow

Publications and source records attributed to J M Chow.

At least 55 records · Page 3Linked to original sources
PubMed1990

Effect of rumen-protected methionine and lysine on casein in milk when diets high in fat or concentrate are fed.

To examine the effect of supplying methionine and lysine on milk N composition, isoenergetic, isonitrogenous diets containing 50:50 with 3.9% added fat or 25:75 forage to concentrate with no added fat were fed with or without rumen-protected methionine and lysine to four primiparous and four multiparous early lactation (36 d in milk) Holstein cows in two 4 x 4 Latin squares. Diets contained 1.7 Mcal NE1 and were fed for ad libitum intake. Periods were 21 d. Rumen-protected methionine and lysine increased total N and casein N percentage with the 3.9% fat, but did not increase total N and casein N percentage with the diet without fat. Whey N percentage was greater with the no fat than with the 3.9% fat diet. Whey N percentage was not affected by adding amino acids. Nonprotein N percentage was greater for the diet with the 3.9% fat than with no fat. Proportions of casein N or whey N to total N were unaffected by treatments. Adding methionine and lysine to diets did not increase yields of total N and casein N. The 3.9% fat diet increased proportions of long-chain (C18:0 and C18:1) and decreased proportions of short- to medium-chain fatty acids (C8 to C16) in milk fat. Plasma nonesterified fatty acids and triglyceride concentrations were greater with the 3.9% fat as compared to the no fat diet. Methionine and lysine decreased plasma triglyceride concentrations with the 3.9% fat diet. Milk yields, DM intakes, and plasma glucose concentrations were unaffected by treatment.

Animal Feed↗
PubMed1989

Radiotherapy or surgery for subclinical cervical node metastases.

This retrospective study compared elective neck dissection with elective neck radiotherapy for the control of subclinical nodal metastases. Four hundred ninety-eight patients with head and neck primary cancers and no clinically apparent neck metastases on initial presentation comprised the study population. Each patient was followed up for at least 5 years to detect failure to control neck metastases and control of the primary tumor at the time of neck recurrence. Analysis of neck recurrences occurring in patients with control of the primary tumor showed that there was no statistically significant difference between elective radiation therapy to the neck and elective neck dissection for oral cavity, oropharyngeal, and laryngeal cancers. The only statistically significant difference was noted for hypopharyngeal cancers, with radiation therapy being more effective than surgery.

Carcinoma, Squamous Cell↗
PubMed1989

Invasive sinonasal polyps causing ophthalmoplegia, exophthalmos, and visual field loss.

In a 20-year-old man with a history of sinonasal polyps, bilateral ophthalmoplegia, exophthalmos, and optic nerve dysfunction developed. Radiologic imaging showed a polypoid mass filling the nose and sinuses, eroding into the pituitary fossa, basal cisterns, and orbits, and compressing the cavernous sinuses. Six months after bilateral maxillary, ethmoid, and sphenoid exploration, ocular motility returned to normal, but there remained mild generalized visual field loss in the right eye. The pathologic specimen showed polypoid respiratory mucosa with acute and chronic inflammation as well as eosinophiles.

Adult↗
PubMed1989

Evaluation of CSF rhinorrhea by computerized tomography with metrizamide.

This study evaluates the ability of metrizamide computerized tomographic cisternography (MCTC) to delineate the site of leakage in patients with cerebrospinal fluid (CSF) rhinorrhea. From 1981 to 1986, thirteen patients were examined by MCTC to localize the site of CSF leakage. A total of 17 studies were performed. Thirteen scans (76%) identified the site of CSF leakage. Nine of these scans were confirmed surgically. The other four scans were performed on patients who refused surgery. Of the 15 scans in patients with active CSF leaks, 13 (87%) were positive. Of the two patients with inactive CSF leaks, neither was positive. One patient is presented in whom MCTC was both diagnostic and therapeutic. In conclusion, MCTC has a high success rate in localizing the site of active CSF leaks.

Adult↗
PubMed1989

Potential use of in vivo proton spectroscopy for head and neck lesions.

Early experience with in vivo MRS has shown its potential for obtaining biochemical information, thus enhancing the diagnostic sensitivity of MRI studies. Further work on combined MRI and in vivo MRS is needed, with the goal of characterization and abnormal conditions according to their spectral patterns and for identification of tumor markers. We presented in this communication our preliminary results. It seems that the resonance from melanin can be used as a marker for melanotic tumors.

Biomarkers, Tumor↗
PubMed1989

Congenital neck masses.

Neck masses are frequently encountered in children. Although they are most often due to past infections, they may be of congenital origin. A neck mass in an adult may also be benign and of congenital origin. Common congenital neck masses include thyroglossal duct cysts, branchial anomalies, cystic hygromas and hemangiomas. Cysts, sinuses and fistulas may arise from the branchial apparatus.

Branchioma↗
PubMed1989

Radiologic assessment preoperative to endoscopic sinus surgery.

At our institution, the screening coronal section CT scan has largely replaced the use of the sinus series for the initial evaluation of patients suspected to have sinus pathology. However, in those patients with obvious mucosal disease on endoscopic examination, the screening coronal section CT scan is bypassed and a complete coronal section CT scan obtained. Axial section CT scans are not routinely obtained and bone windows are consistently selected for viewing.

Endoscopy↗
PubMed1988

Kinetics and subsite mapping of a D-xylobiose- and D-xylose-producing Aspergillus niger endo-(1----4)-beta-D-xylanase.

A previously described endo-(1----4)-beta-D-xylanase produced by Aspergillus niger was allowed to react with linear unlabeled and labeled D-xylo-oligosaccharides ranging from D-xylotriose to D-xylo-octaose. No evidence of multiple attack or of condensation and trans-D-xylosylation reactions was found. Maximum rates and Michaelis constants were measured at 40 degrees and pH 4.85. The former increased with increasing chain-length from D-xylotriose through D-xylohexaose to approximately 70% of that on soluble larchwood D-xylan, and then decreased slightly for D-xyloheptaose and D-xylo-octaose. Michaelis constants decreased monotonically with increasing chain-length. Bond-cleavage frequencies were highest near the reducing end of short substrates, with the locus of highest frequencies moving towards the middle of larger substrates. These data indicated that the endo-D-xylanase has five main subsites, with the catalytic site located between the third and fourth subsites, counting from the nonreducing end of the bound substrate. The subsite to the nonreducing side of the catalytic site strongly repels its corresponding D-xylosyl residue, while the two subsites farther towards the nonreducing end of the substrate strongly attract their corresponding residues. The subsite to the reducing side of the catalytic site moderately attracts D-xylosyl residues, while the next one towards the reducing end has a high affinity for them. The residual error of the numerical estimation was allocated largely to the Michaelis constants of the different D-xylo-oligosaccharides, whose calculated values were appreciably smaller than measured values, especially for shorter substrates. This suggests that the subsite model cannot fully account for the experimental data. Estimated and measured values of maximum rates, bond-cleavage frequencies, and dissociation constant when the active site is fully occupied by substrate agreed more closely with each other.

Aspergillus niger↗
PubMed1988

Sudden sensorineural hearing loss.

Sudden sensorineural hearing loss has many causes and treatments. The family physician can identify the hearing loss, perform audiometry, identify likely systemic causes and counsel the patient on the prognosis. Most patients are ultimately found to have idiopathic sensorineural hearing loss, and the spontaneous recovery rate is high. If no improvement occurs within one month, evaluation to rule out tumor is recommended.

Adolescent↗
PubMed1988

Head and neck: high field magnetic resonance imaging versus computed tomography.

A comparative review of head and neck lesions examined with both CT and MRI showed that the location and extent of lesions can be more precisely evaluated with MRI. MRI allows better differentiation of neurogenic tumors from other lesions. Vascular structures are easily visualized on MRI without intravenous contrast and can easily be differentiated from lymph nodes. However, cystic lesions and necrotic nodes sometimes could not be differentiated from solid lesions when using MRI.

Branchioma↗
PubMed1986

Primary mandibular reconstruction using the AO reconstruction plate.

Primary reconstruction of segmental defects of the mandible following cancer resection remains a major problem. In 1976, a stainless steel plate was developed by AO/ASIF (Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation) for mandibular reconstruction. This plate completely stabilizes both mandibular stumps without the need for intermaxillary or external fixation. In addition, when bone grafting is performed, the design of this plate promotes revascularization by allowing maximal contact between grafted cancellous bone and surrounding soft tissue. Since April 1985, we have used this reconstruction plate in six patients undergoing composite resection. The technique did not compromise cancer resection, excessively prolong operating time, or alter postoperative management. All six patients have retained the AO reconstruction plate and have been reconstructed successfully with achievement of satisfactory function and cosmesis.

Adult↗
PubMed1986

Nonsquamous tumors of the oral cavity.

The clinical presentations of various nonsquamous tumors of the oral cavity are reviewed, along with their gross pathology, histology, and treatment. Survival rates are presented for those neoplasms that occur frequently enough to allow meaningful analysis of various modes of therapy.

Chondroma↗
PubMedDate not supplied

Preoperative evaluation for partial laryngectomy.

The object of this study was to determine if pulmonary function tests were necessary in the preoperative evaluation of potential candidates for conservation laryngeal procedures. In addition, pulmonary complications from a series of partial laryngectomies were examined and correlated with a previous history of chronic obstructive lung disease. Ninety-four patients with laryngeal tumors amenable to a partial procedure were assessed preoperatively by testing their pulmonary function by stair-climbing; they were considered to possess enough pulmonary function to permit a partial procedure. Pulmonary function tests were obtained in 69 of these patients. Measurements of vital capacity and forced expiratory volume in 1-second were reviewed and correlated with the postoperative development of pulmonary complications to determine if these tests of pulmonary function could reliably predict which patients would be more prone to developing pulmonary complications. The results indicated that pulmonary function tests or a prior history of chronic obstructive pulmonary disease (COPD) could not reliably predict postoperative complications.

Adult↗
PubMedDate not supplied

Proton nuclear magnetic resonance spectroscopy of plasma lipoproteins in head and neck cancer patients.

Proton nuclear magnetic resonance spectroscopy was used to evaluate changes in plasma lipoproteins in patients with squamous cell head and neck cancer. Plasma from 14 patients was analyzed by proton nuclear magnetic resonance spectroscopy, and line widths and fast and slow methyl and methylene transverse relaxation values were obtained. In addition, the lipid and lipoprotein concentrations in the sera of these patients were measured by standard biochemical techniques. Preliminary results suggested that squamous cell carcinomas of the head and neck with nodal metastases are associated with measureable changes in slow methylene transverse relaxation values, as compared with controls. These findings indicate the presence of a new lipoprotein complex in patients with squamous cell carcinomas of the head and neck with nodal metastases.

Adult↗