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Biomedical subjects

R K Pullarkat

Publications and source records attributed to R K Pullarkat.

47 records · Page 3Linked to original sources
PubMed1979

On the ultrastructural diversity and essence of residual bodies in neuronal ceroid-lipofuscinosis.

In 4 patients with neuronal ceroid-lipofuscinoses (NCL) (3 patients with the junvenile type, 1 patient with the late infantile type), the ultrastructural spectrum of residual bodies in the central and peripheral nervous system presented curvilinear profiles in all cases and regions investigated and many more ultrastructural patterns within and beyond regions commonly accessible to biopsy, probably due to age dependence, local tissue and cellular biochemical factors. Sampling from basal ganglia especially yielded combined curvilinear-fingerpint bodies, from peripheral ganglia additional membranous bodies. Residual bodies in NCL were present in almost every cell type, similar to the distribution of regular lipofuscin. Although the classical subgroups of NCL contain electronmicroscopically well defined residual bodies, permitting distinction of the late infantile type from the juvenile type, the ultrastructural differences are more of a quantitative than of a qualitative nature. However, they are not pathognomonic. N.m.r. spectra of ceroid and lipofuscin support the concept of their biochemical similarity, and argue against the proposition that they contain a single major component.

Brain↗
PubMed1978

Leukocyte docosahexaenoic acid in juvenile form of ceroid-lipofuscinosis.

Leukocyte glycerolipid fatty acid compositions were determined in four patients of juvenile form of neuronal ceroid-lipofuscinosis (Battens disease), their parents and age-matched controls. A 54 to 93% reduction in docosahexaenoic acid (22:6, n-3) was noted in patient leukocytes. The parents also showed reduction in docosahexaenoic acid content, but to a lesser degree. The levels of linolenic family (n-6) polyunsaturated fatty acids were unchanged suggesting that the metabolic defect in this disease is specific to the linolenic family (n-3) of fatty acids.

Adolescent↗
PubMed1978

Pigment variant of lipofuscinosis.

A woman had a progressive neurologic syndrome beginning at age 3 and lasting for three decades. Clinical manifestations included severe mental deterioration, spastic paralysis, myoclonus, and tremors. A postmortem examination showed ubiquitous infiltration of neurons by lipofuscin and deposits of pigment in the globus pallidus and substantia nigra, as well as senile changes of nerve cells. Biochemical investigation of brain lipids showed an alteration of fatty acid composition of serine phosphoglycerides.

Adult↗
PubMed1977

Studies on the hydrogen belts of membranes: II. Non-electrolyte permeability of liposomes of diester, diether, and dialkyl phosphatidylcholine and cholesterol.

We have postulated the existence of lipid-lipid and protein-lipid hydrogen bonding in the hydrogen belts of membranes, i.e., the regions of hydrogen bond acceptors (carbonyl oxygens of esters and amides) and hydrogen bond donors (hydroxyls of cholesterol, sphingosine, proteins, water). To assess the possible effects of modifications of the hydrogen belts on membrane permeability, we prepared a diester phosphatidylcholine and two analogs lacking carbonyl oxygens, a diether and a dialkyl phosphatidylcholine, care being taken to synthesize lipids of identical efficient hydrophobic chain length. Relative permeation rates for glycerol and urea were determined by osmotic swelling of liposomes containing the phospholipids alone or with an equimolar quantity of cholesterol, with 4 mole % of dioleylphosphate added. The permeation rates of both solutes were similar for all three lipids, with Arrhenius activation energies deltaE* around 16 kcal/mole. Cholesterol reduced the permeability of all three membranes. The activation energy deltaE* of permeation did not change for diester and dialkyl phosphatidylcholine with cholesterol, but was lower by about 5 kcal/mole for the diether lipid with cholesterol. This corresponds to a reduction in the entropy of activation deltadeltaS*approximately-16 cal/mole/degree. We interpret the results as supporting the hypothesis of interaction between cholesterol hydroxyl and phospholipid carbonyl.

Cholesterol↗
PubMed1976

Fatty-acid composition of rat brain lipids. Determined by support-coated open-tubular gas chromatography.

The nonhydroxy fatty acid composition of rat brain lipids (except gangliosides) was determined by support-coated open-tubular (SCOT) gas chromatography. Fatty acids of both odd and even chain lengths ranging from C14 to C26 were detected. Brain lipids contained 49% saturated, 29% monounsaturated, and 22% polyunsaturated fatty acids. Monoenoic fatty acids were mainly of the omega-9 and omega-7 series with minor amounts of omega-10 and amega-11 isomers. Dienes and trienes consisted of omega-6, amega-7, and omega-9 series. Tetraenes were of the omega-6 series. Small amounts of omega-6 and omega-3 pentaenes were detected. The most abundant polyunsaturated fatty acid was 22:6omega-3. The advantages of support-coated open-tubular columns over wall-coated open-tubular columns for the analysis of brain lipid fatty acids are discussed.

Animals↗
PubMedDate not supplied

Brain lysosomal hydrolases in neuronal ceroid-lipofuscinoses.

Although the neuronal ceroid-lipofuscinoses (NCLs) are often referred to as lysosomal storage disorders, information on brain lysosomal hydrolases in NCLs is not available. We have determined the specific activities of several acid hydrolases in postmortem brain gray matter of infantile (INCL), late infantile (LINCL), juvenile (JNCL), and adult (ANCL) forms of NCL, patients affected with other neurological disorders (ON), and normal controls. The specific activities of beta-hexosaminidase A and B were significantly high in JNCL gray matter, whereas in LINCL, the increase is significant only in beta-hexosaminidase compared to the controls. A significant increase in the activities of alpha-mannosidase, beta-glucuronidase, and acid phosphatase was also observed in LINCL and JNCL patients compared to the control values. beta-galactosidase activity was also found to be elevated in JNCL brains over the controls. In contrast, activities of beta-glucosidase and sialidase appeared to be lowered in INCL and LINCL. On the other hand, alpha-fucosidase, beta-mannosidase, and sulfatase were unaffected in NCLs brains. Thus, the present data indicate NCLs related abnormalities in some of the acid hydrolases in brain gray matter, which are primarily glycoproteins of lysosomal origin. These data in conjuction with the reported association of sphingolipid activator proteins (SAP) A and D and lysosomal glycoproteins with NCL storage bodies imply abberations in the glycoconjugate metabolism and lysosomal function.

Acid Phosphatase↗
PubMedDate not supplied

Elevated urinary dolichol levels in chronic alcoholics.

Urinary dolichol (long chain 2,3-dihydropolyprenol) levels were determined in 23 chronic alcoholics and 15 normal subjects using high performance liquid chromatography. Normal dolichol levels were 4.7 +/- 2.8 ng/ml whereas, in chronic alcoholics, this value was increased to 61.1 +/- 44.6 ng/ml. Stopping the intake of alcohol for a few weeks brought the urinary dolichol gradually to the normal level.

Adult↗
PubMedDate not supplied

A lysosomal pepstatin-insensitive proteinase as a novel biomarker for breast carcinoma.

Lysosomal proteinases play an important role in the turnover of intracellular proteins, and acidic proteinases such as cathepsin D are known to be increased in breast carcinoma. In the present study the activity of a newly discovered acidic lysosomal pepstatin-insensitive proteinase (CLN2p) was measured in breast tissues by the most sensitive and highly specific assay that we had developed for the diagnosis of late-infantile neuronal ceroid lipofuscinosis (LINCL) (2). Samples from eight normal subjects undergoing reductive mammoplasty and 200 patients with primary breast carcinoma were analyzed. The results suggest a two- to seventeen-fold higher CLN2p activity in tumors, which was significantly and positively correlated with already known breast cancer biomarkers such as levels of cathepsin D, estrogen receptor and progesterone receptor. These results suggest a diagnostic and prognostic potential for this novel acid proteinase in breast cancer.

Aminopeptidases↗