Biomedical subjects

N S al-Zaid

Publications and source records attributed to N S al-Zaid.

9 recordsLinked to original sources

PubMed1991

Changes in collagen content of the diaphragm in rats of different ages.

Rat diaphragm showed a nine to ten-fold increase in the dry and wet weights and a four-fold increase in its surface area between 21 and 540 days of age. The increase was the most rapid between days 21 and 90, thereafter a non-significant trend of increase was maintained at least up to 360 days of age followed by a tendency to decrease. The total collagen content of the diaphragm paralleled the increase in surface area with progressing age. The collagen content significantly dropped when expressed relative to the dry weight of the diaphragm, between 21 and 90 days of age. This trend was maintained till 180 days of age but thereafter significantly rise was seen. These later changes may be due to elenated synthesis and/or reduced degradation of collagen, and may contribute to the decline in contractility of the diaphragm as age advances.

Aging↗

PubMed1990

The collagen composition of the dystrophic hamster diaphragm.

1. Diaphragms from BIO 14.6 dystrophic hamsters had lower dry weights and higher collagen content than did controls, BIO F1B. 2. The increase in pepsin-solubilized collagen affected mainly types III and V, and there was a concomitant decrease in the beta and high molecular weight (HMW) collagen aggregates. 3. These findings are similar to the observations in myotonia congenita and imply that the dystrophic process increases collagen synthesis. 4. In addition, there is possibly a genetic mutation of amino acids at points of contact of collagen monomers. 5. Alternatively, there may be reduced hydroxylation of lysine residues and hence in the degree of glycosylation of collagen resulting in decreased cross-linking and aggregation.

Animals↗

PubMed1990

Collagen of the dystrophic hamster diaphragm.

The collagen content of the diaphragm was measured in normal and dystrophic hamsters aged 130 and 270 days. The diaphragm collagen content was greater in dystrophic hamsters than in control hamsters of the same age. The effect was greater in the older hamsters whether the collagen content was expressed in terms of the percentage of dry weight, in relation to surface area, or as total collagen. This increase was apparently at the expense of muscle tissue and may be a major factor contributing to respiratory muscle weakness as dystrophy advances.

Animals↗

PubMed1989

Comparison of performance of students from different high school systems in medical sciences at Kuwait University.

Data, although limited, question the validity of the formula applied for admission to the medical school in which high school grades are the only preselection variable applied. Comparison between two groups of students from two different high school systems in Kuwait was carried out to determine if the admission criteria used currently for entry to the medical school are equally valid for both groups. The results are based on the students' performances in the first three-semester programme of medical sciences. Subjects covered were anatomy, physiology, biochemistry and behavioural sciences. The group derived from the High School National Diploma performed significantly better with a percentage pass rate of 82% while of those who were derived from the Course Credit System only 61% passed the final examination. In addition, only one of the latter group attained total marks of more than 80% compared to 12 students from the National Diploma group. The percentage failure according to subjects was consistently higher among the Course Credit graduates in all the subjects. All differences between the two groups are statistically significant (P less than 0.001).

Achievement↗

PubMed1989

Changes in amniotic fluid cathepsins with gestational age.

Activities of the cysteine proteinases cathepsins B and H and of the chymotrypsin-like cathepsin G were determined in amniotic fluid of rats during the last third of gestation. Activities of cathepsins B and G were found to significantly increase with increasing gestational age while cathepsin H activity decreased. It was concluded that cathepsins may participate in the destabilization of fetal membranes and therefore may contribute to their rupture.

Amniotic Fluid↗

PubMed1988

Premature rupture of fetal membranes changes in collagen type.

Collagen from the chorioamnion units from premature and term pregnancies was solubilized by limited pepsin digestion and subjected to SDS-PAG electrophoresis. Collagen types were quantitated by densitometry. It was found that collagen type III decreases and collagen type V tends to increase as gestational age advances. Investigating the relative abundance of collagen types at various membrane sites from term pregnancies revealed that type V decreases in the amnion as the rupture site is approached. It is concluded that since type V collagen is more resistant to collagenases, its decrease may predispose that particular site to rupture.

Amnion↗

PubMed1988

Muscle collagen content in diabetic rats.

Collagen content (mg/dl of dry weight) was measured biochemically in the extensor digitorum longus and the soleus muscle in rats. Comparison of muscles from diabetic (induced by intraperitoneal streptozotocin injection /60 mg/kg body weight/) and non diabetic controls showed an increase in the collagen content of the extensor digitorum longus, and little change in the soleus. The differences did not attain statistical significance indicating that the accelerated collagen ageing attributed to diabetes may not necessarily be true in all tissues.

Aging↗

PubMedDate not supplied

Heterogeneity of the histological features along the course of the facial vein of the desert camel (Camelus dromedarius): relevance to brain cooling.

Sections from different parts along the facial vein of the camel (Camelus dromedarius) were examined by light microscopy. The results demonstrated heterogeneity among the various segments. Particular attention was paid to a specific area in the buccal region which was previously shown by physiological experiments to have a temperature-dependent myogenic tone. The morphology of that area showed highly thickened media with prominent bands of circularly disposed smooth muscles infiltrating both the intima and the adventitia. The morphology described in this study correlates well with the function and gives further credence to the proposed role of the facial vein in cranial thermoregulation particularly under heat stress.

Animals↗

PubMedDate not supplied

Urine levels of type 1 collagen cross-linked N-telopeptides and deoxypyridinoline correlate with disease activity in rheumatoid arthritis.

OBJECTIVES: The aim of this study was to find out whether spot urinary concentrations of type 1 collagen cross-linked N-telopeptides (NTx) and deoxypyridinoline (Pyrilinks-D) can differentiate between active and inactive disease in rheumatoid arthritis (RA) and to investigate the extent to which they correlate with indices of disease activity. METHODS: Using enzyme-linked immunosorbent assays, the concentrations of NTx and Pyrilinks-D were estimated in spot urine samples from 25 females with active disease, 25 females with inactive disease, and in 25 controls. RESULTS: In Patients with active disease, urinary concentrations of NTx and Pyrilinks-D were significantly higher (p < 0.01) than in those with inactive disease or in healthy controls. In active disease there were significant positive correlation between urinary NTx and ESR, the swollen joint count, the tender joint count, and the patient's global assessment.

Adult↗