PubMed Health⌕ Search

Biomedical subjects

M Marks

Publications and source records attributed to M Marks.

At least 73 records · Page 4Linked to original sources
PubMed1979

Hemodynamics in teenagers and asthmatic children during exercise.

Seventeen normal teenagers and eight asthmatic children were studied during submaximal exercise on a bicycle ergometer. A modification of a noninvasive multiple gas rebreathing method was utilized for the estimation of pulmonary capillary blood flow (Qc), diffusing capacity (DL), oxygen consumption (VO2), functional residual capacity (FRC), and pulmonary tissue plus capillary blood volume (VTPC). Significant increases in Qc, DL, VO2, and heart rate occurred in both groups of subjects. Regression equation of Qc equaled 6.0 + 0.0078 VO2 (ml/min) in the teenagers and 3.39 + 0.0082 X VO2 (ml/min) in the asthmatic children. The values of DL as a function of VO2 in both groups were similar to previously reported data. No significant changes in FRC or VTPC occurred in either group during exercise. This method appears to be an acceptable noninvasive way of studying exercise physiology in healthy or sick children.

Adolescent↗
PubMed1979

Isoenzymes of beta-hexosaminidase from normal rat colon and colonic carcinoma.

N-Acetyl-beta-D-hexosaminidase isolated from normal rat colon was compared to that obtained from a transplantable rat colonic carcinoma. Levels of total hexosaminidase from purified epithelial cells of normal colon were similar to those from purified malignant cells from the transplantable tumor. Cultured malignant cells had significantly higher levels of activity than did freshly purified tumor cells. Isoelectric focusing of hexosaminidase from normal rat colon indicated approximately equal amounts of A (pI 5.0 ) and B (pI 8.1) isoenzyme activity. The B isoenzyme (normal cell) was more stable to heat inactivation than was the A isoenzyme and had significantly higher activity at low pH's. In contrast, the B isoenzyme from the tumor was relatively unstable to heat and low pH.

Animals↗
PubMed1977

Kinetic studies on 3-hydroxykynureninase from rat liver.

3-Hydroxykynureninase was purified from rat liver. The Michaelis constants for L-kynurenine and L-3-hydroxykynurenine were determined to be 2.33 X 10(-4)M and 6.85 X 10(-5)M, respectively, at pH 8.41 and 37 degrees. With L-kynurenine as substrate, the enzyme was competitively inhibited by L-alanine, 3-hydroxyanthranilic acid, and several other compounds which contained structural features of either amino acid or aryl portions of the substrate. The effect of pH on the initial velocity, maximal velocity, and Michaelis constant, using L-kynurenine as substrate, was studied. Maximal velocity was strongly pH-dependent, with a maximum at pH 8.4. The Michaelis constant decreased from 11.4 X 10(-4)M at pH 7.1 to 1.30 X 10(-4)M at pH 9.0. Logarithmic plots of these data showed pKa's for functional groups ionizing in the enzyme-substrate complex and free enzyme active center of 7.6 and 8.5, respectively. Possible groups responsible for these ionizations were discussed.

Alanine↗
PubMed1977

Bronchial adenoma. A clinicopathologic study.

Among 28 patients with bronchial adenomas, 24 adenomas (86%) were of the carcinoid type. The 28 bronchial adenomas provided an incidence of 0.6% of all primary lung tumors seen in our institutions. There was a slightly greater preponderance of female patients and a greater incidence of the lision occurring in the right bronchopulmonary tree than the left. Symptoms of bronchial adenoma may exist for many years before the condition is diagnosed, and prolonged survival is recorded, even in the absence of surgical treatment. Although pneumonectomy was performed in several patients, lobectomy, bronchoplastic procedures, or sleeve resection of the affected area are generally recommended.

Adenoma↗
PubMed1968

Rehabilitation.

Explore the source record for details and available documents.

Adolescent↗
PubMed1967

Rehabilitation.

Explore the source record for details and available documents.

Adolescent↗
PubMed1966

Rehabilitation.

Explore the source record for details and available documents.

Humans↗
PubMed1965

Rehabilitation.

Explore the source record for details and available documents.

Adult↗
PubMedDate not supplied

Merkel cell carcinoma of the ear.

All the consultants agree that, given this patient's history, a common skin tumor like squamous cell or basal cell carcinoma is unlikely. Melanoma or Merkel cell carcinoma belong in the differential. Interestingly, the consultants all suggest a biopsy of the lesion prior to other testing, and because this tumor is so accessible, a biopsy should not interfere with further testing or treatment. Drs. Weymuller and Marks would then proceed with a CT scan; Dr. Ridge favors an MRI scan. While a chest-ray is in order to rule out metastases, Dr. Weymuller also suggests immunocytochemistry. All the experts agree that the primary tumor should be excised. Dr. Weymuller would perform a total parotidectomy with facial nerve preservation, while Drs. Marks and Ridge suggest a superficial parotidectomy with facial nerve preservation. Drs. Weymuller and Ridge would also perform a modified radical neck dissection. In the absence of cervical disease, Dr. Marks would treat the neck primarily with radiotherapy. Only Dr. Weymuller favors immediate reconstruction and would use a lower trapezius island flap or a large rotational flap. Drs. Marks and Ridge prefer primary closure or skin graft. Drs. Weymuller and Ridge would treat this patient with combined therapy, giving radiotherapy to the primary area and the neck postoperatively at a dose of 55-60 Gy. However, Dr. Marks would treat the primary site postoperatively and the neck primarily with radiotherapy. He would treat the primary site with 59.40 Gy and the neck with 50.40 Gy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Clinical aspects of DWI.

Diffusion-weighted MR imaging (DWI) is capable of imaging ischemia-induced changes in water protons in either animal or man. Technical developments are described that allow the routine clinical utility of DWI in a stroke setting to provide objective criteria beyond the neurological exam by which the pathophysiology of stroke can be evaluated. To date, DWI has provided unique information concerning detection and evaluation of acute, symptomatic lesions from older, chronic strokes, detection and localization of small deep infarcts and reversible ischemic neurologic deficits and transient ischemia. Clinical DWI studies suggest that the temporal behaviour of ADC can critically improve the evaluation of clinical ischemia.

Aged↗
PubMedDate not supplied

The extended microbiology of group A streptococcal pharyngitis. Observations during a double-blind controlled study of cephalexin twice versus four-times daily.

In a double-blind controlled study we compared the effectiveness of cephalexin b.i.d. versus q.i.d. in the treatment of group A streptococcal pharyngitis in 65 children. Clinical improvement was noted in 64 patients (98%) and bacteriologic cure in 60 (92%). Despite good compliance, three bacteriologic failures were noted in the q.i.d., and two in the b.i.d. treatment groups. Two of these five were carriers. Significant antibody responses were observed in 61% of the patients by at least one of three tests (ASO, anti-DNase B, Streptozyme). We also investigated the extended microbiology of streptococcal pharyngitis by looking for the presence of viruses, chlamydia and beta-lactamase producing organisms in the pharynx. Respiratory viruses were isolated concomitantly with Streptococcus pyogenes in six patients. Beta-lactamase producing bacteria were present in the pharynx of 98% of the patients at the initiation of treatment and comprised 1-98% of the total bacterial flora. The beta-lactamase producing flora did not significantly change with cephalexin therapy.

Bacteria↗
PubMedDate not supplied

S--s--U-- phenotype in the coloured population of Cape Town: problems encountered in paternity tests.

Two Cape Coloured persons of mixed White, Khoikhoi, Malay, Black parentage in Cape Town whole red cells were found to be S--s--U-- establish that the rare Su allele is present in this population group. The most likely source of the Su allele in them is the non-indigenous Black slaves who were brought to the Cape in the early years of White settlement there. In two paternity suits involving Cape Coloured persons, maternal and paternal exclusions were present unless the inheritance of an MSu or an NSu chromosome was postulated, and MS, NS and Ns chromosomes were seen to accompany He+ alleles in them.

Adolescent↗
PubMedDate not supplied

Retrospective versus prospective self-rating of anxiety symptoms and cognitions.

The discrepancy between retrospective and prospective rating of anxiety symptoms and cognition was examined in 20 agoraphobics. Subjects were required to complete a checklist of symptoms and cognitions during exposure to an agoraphobic situation. and then to complete a similar set retrospectively. More cognitions were rated retrospectively than prospectively, with the discrepancy especially evident for cognitions about physical catastrophe. In contrast, there was no discrepancy between anxiety symptoms rated prospectively versus retrospectively. This may be because anxiety symptoms are easier for patients to identify than cognitions. require less introspection. or are less affected by context than cognition. Implications of the findings are discussed and suggestions for future research are made.

Adult↗
PubMedDate not supplied

Cranial hypertrophic interstitial neuropathy.

The authors describe a patient with complex cranial neuropathy caused by pathologically proved hypertrophic interstitial neuropathy. Plain and contrast-enhanced MR studies were performed prior to surgical exploration. Surgical complications caused the patient's death and a complete pathology study was done. Though nonspecific, MR proved helpful in determining the extent of disease and areas of anatomic involvement.

Cranial Nerve Diseases↗