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Biomedical subjects

M A Ali

Publications and source records attributed to M A Ali.

At least 217 records · Page 12Linked to original sources
PubMed1981

Application of electron microscopy in the interpretation of fine-needle aspiration biopsies.

A series of 31 fine-needle aspiration biopsies were studied ultrastructurally in order to evaluate the usefulness of electron microscopy in the diagnosis of aspiration biopsies. In seven cases, the electron microscopic findings were crucial to the diagnosis. In the remaining cases, electron microscopy helped to confirm the light microscopic diagnosis. In addition, in a number of cases the diagnosis rendered following electron microscopy was much more precise and specific than was possible with light microscopy alone. It is concluded that electron microscopy has a definite place in the diagnosis of fine-needle aspiration biopsies and should be increasingly utilized on a selective basis.

Adolescent↗
PubMed1981

Ultrastructure of the pineal organ of the killifish, Fundulus heteroclitus, with special reference to the secretory function.

The pineal organ of the killifish, Fundulus heteroclitus, was investigated by electron microscopy under experimental conditions; its general and characteristic features are discussed with respect to the photosensory and secretory function. The strongly convoluted pineal epithelium is usually composed of photoreceptor, ganglion and supporting cells. In addition to the well-differentiated photosensory apparatus, the photoreceptor cell contains presumably immature dense-cored vesicles (140-220 nm in diameter) associated with a well-developed granular endoplasmic reticulum in the perinuclear region and the basal process. These dense-cored vesicles appear rather prominent in fish subjected to darkness. The ganglion cell shows the typical features of a nerve cell; granular endoplasmic reticulum, polysomes, mitochondria and Golgi apparatus are scattered in the electron-lucent cytoplasm around the spherical or oval nucleus. The dendrites of these cells divide into smaller branches and form many sensory synapses with the photoreceptor basal processes. Lipid droplets appear exclusively in the supporting cell, which also contains well-developed granular endoplasmic reticulum and Golgi apparatus. Cytoplasmic protrusions filled with compact dense-cored vesicles (90-220 nm in diameter) are found in dark-adapted fish. The origin of these cytoplasmic protrusions, however, remains unresolved. Thus, the pineal organ of the killifish contains two types of dense-cored vesicles which appear predominantly in darkness. The ultrastructural results suggest that the pineal organ of fish functions not only as a photoreceptor but also as a secretory organ.

Adaptation, Ocular↗
PubMed1981

Microtubules and 10 nm-filaments in the retinal pigment epithelium during the diurnal light-dark-cycle.

Microtubules and 10 nm-filaments appear to be involved in the functions of the retinal pigment epithelium (RPE). The presence of microtubules in the RPE of light-adapted eyes, but not in dark-adapted eyes, suggests that they may be involved primarily in organelle movement. On the other hand, the random and constant presence of 10 nm-filaments within the basal portion of the PE implies a cytoskeletal role for these filaments.

Adaptation, Ocular↗
PubMed1981

Sickle cell traits in Canada. Trimodal distribution of Hb S as a result of interaction with alpha-thalassaemia gene.

A trimodal distribution of the amounts of Hb S in 56 sickle cell heterozygotes was observed. The variable amounts of Hb S were directly related to the mean cell volume and the mean cell Hb and were a result of the difference in net synthesis of Hb S due to the presence of the alpha-thalassaemia. Double heterozygotes for the Hb S and alpha-thalassaemia-1 genes, besides having a lower amount of Hb S in the red blood cells, were found to have lower Hb and slightly elevated Hb A2 levels.

Adult↗
PubMed1981

[Retinal adaptations to habitat].

Vertebrates have, through the process of evolution, adapted to their photic environment. This is well manifested in the retinal adaptations to various habitats. Although all vertebrates are considered, emphasis is placed on fishes because they form about 50% of the vertebrate species. In addition, they occupy a wide range of habitats, thus retinal modifications of fishes serve as models for all other vertebrates. The present article reviews morphological, physiological and biochemical retinal adaptations. The quality and quantity of light reaching the aquatic organism are functions of the incident light as well as the aquatic environment. Thus, in well lit, clear waters fishes are arhythmic and possess almost equal populations of rods and cones; whereas fishes in dimly lit environments (due to turbidity or depth) have retinas that are more specialised for high sensitivity-multi-banked retinas, long outer segments, grouped photoreceptors, hypertrophied ellipsoid mitochondria, reflecting tapetum. Similarly, the ratio and distribution of visual pigments (rhodopsin and porphyropsin) and S-potential change with respect to fresh/sea water, clear/turbid water and air/aquatic environments. Thus, in fresh waters, where the photic environment shifts to longer wavelengths, porphyropsin predominates; while in land vertebrates and almost all marine fishes the dominant pigment is rhodopsin. With respect to the latter, fishes in turbid, greenish or yellowish coastal waters have 'rhodopsins' with lambda mas above 500 nm; fishes in clear coastal habitats have 'rhodopsins' with lambda max near 500 nm; while those in the blue-lit environment of deep seas have lambda max below 500 nm. The retinal pigment composition is also associated with habitat changes during diadromous migrations in fishes or during amphibian metamorphosis. It is interesting to note that the dorsal and ventral retinas of Rana catesbeiana and Anableps microlepis which view aquatic and aerial environments, respectively, show a predominately porphyropsin-rich dorsal retina compared to a rhodopsin-rich ventral retina. Similar shifts in the S-potential are observed with change in habitats. Fresh water fishes exhibit L-responses with lambda max in longer wavelengths compared to marine fishes where the maximum of the L-response shifted towards shorter wavelengths.

Adaptation, Physiological↗
PubMed1980

Responses of pineal photoreceptors in the brook and rainbow trout.

Electron microscopy of the pineal receptor cells in light- and dark-adapted brook trout, Salvelinus fontinalis and the rainbow trout, Salmo gairdneri, revealed no significant differences in the tubular and filamentous elements of the inner segment, neck and supranuclear regions. However, changes in synaptic relations between the photoreceptor and nerve cell were induced by light and darkness. In the light-adapted state, the synaptic relationship between axon terminals and photoreceptor basal processes predominates, while in darkness the synapses between photoreceptor basal processes and ganglion cell dendrites are more prominent. Further, in darkness, the photoreceptor basal processes show a number of synaptic vesicles and synaptic ribbons. These findings suggest that the sensory function of the fish pineal is enhanced during darkness but inhibited by light, and that the synaptic relationships are involved in the control of sensory activity in the pineal photoreceptor and ganglion cells. These results corroborate those of electrophysiological studies in that the maximal spontaneous discharge frequency of the ganglion cells occurs in the dark, and it also shows a burst when light is removed. The "typical" chemical synapse between the axon terminal and the photoreceptor basal process in light seems to function as an inhibitor.

Adaptation, Physiological↗
PubMed1980

Oral therapy in children with cholera: a comparison of sucrose and glucose electrolyte solutions.

We performed a double-blind trial comparing sucrose electrolyte oral solution with glucose electrolyte oral solution in children less than 5 years of age with severe cholera-like diarrhea. Of 111 patients studied (102 with bacteriologically confirmed cholera), 55 received sucrose solution and 56 received glucose solution. The success rates, as defined by the absence of the need to give unscheduled intravenous therapy, were similar in the two groups (73% and 77% in the sucrose and glucose groups, respectively). There was no difference in purging rates between the two groups. The primary determinant of success for oral fluid regardless of the sugar was the purging rate. Sucrose malabsorption was responsible for oral therapy failure in one child. This study demonstrates that sucrose is an effective alternative to glucose in the oral therapy solution, but either must be used in conjunction with intravenous solution when treating severe dehydrating diarrhea.

Administration, Oral↗
PubMed1980

Lepromatous leprosy presenting as orchitis.

Two patients with lepromatous leprosy presenting initially because of lepromatous orchitis are reported. These cases are unusual because they were diagnosed as lepromatous orchitis at a stage when no other evidence of leprosy was present. Generalized skin lesions characteristic of lepromatous leprosy subsequently developed in one of these patients. It is suggested that lepromatous orchitis should be actively considered in the differential diagnosis of orchitis and infertility.

Adult↗
PubMed1980

Haemoglobin D Los Angeles, D-beta +-thalassaemia, and D-beta o-thalassaemia. A report of two Canadian families.

The first 2 Canadian cases of combinations of Hb D Los Angeles and beta-thalassaemia were found in an Italian family and an East Indian family in Hamilton, Ont. The structure of the Hb D variant was identified by radioimmunoassay. The beta +-thalassaemia trait in the Italian family and the beta o-thalassaemia trait in the East Indian family were confirmed by studies of globin chain synthesis. Previous cases of Hb D-beta-thalassaemia were summarized and family studies of the 2 new cases were presented.

Adolescent↗
PubMed1980

Primary hepatocelluar carcinoma in Saudi Arabia. A clinicopathological study of 54 cases.

A high incidence of primary hepatocelluar carcinoma in the Orient and Africa has been reported. It is also seen frequently in Saudi Arabia. In a series of 54 consecutive patients diagnosed histologically, the male to female ratio was 10:1--the highest reported. The peak age was between 40-60 years and the mean survival was eight months. This is in contrast to hepatocelluar carcinoma in Africa where the age is between 25-35 years and the disease runs a quick downhill course simulating an abscess. Macronodular cirrhosis was diagnosed histologically or suggested clinically in 80% of the cases. Serum was positive for HBsAg in 55% of the patients, compared with 8% in healthy blood donors. These figures are as significant as reports from high incidence areas and point strongly to a possible causal relationship between HBV infection and the development of primary hepatocellular carcinoma.

Adult↗