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Biomedical subjects

B Ahluwalia

Publications and source records attributed to B Ahluwalia.

At least 19 recordsLinked to original sources
PubMed1992

Biphasic protein kinase C translocation in PC12 cells in response to short-term and long-term ethanol exposure.

Short-term and long-term effects of ethanol on protein kinase C (PKC) activity and PKC translocation from cytosol to membrane were examined in PC12 cells, a clonal cell line of neural crest origin. Treatment of PC12 cells with ethanol (30-100 mM) for 2 hr had no effect on PKC activity and PKC translocation. When PC12 cells were treated with 100 mM ethanol for 18, 44 and 74 hr, there was a biphasic effect on PKC translocation. At 18 and 44 hr ethanol treatment, PKC translocation was significantly (P < 0.001) increased, at 74 hr ethanol treatment, there was a significant decrease (P < 0.05). Less than 100 mM of ethanol had no effect on PKC activity and PKC translocation. Cyclic AMP and cyclic GMP-dependent protein kinase had no effect on PKC translocation. These findings indicate that biphasic PKC translocation from cytosol to membrane forms the basis of acute and chronic effects of ethanol on neurotransmission.

Animals↗
PubMed1991

Evidence that gonadal hormone levels in amniotic fluid are decreased in males born to alcohol users in humans.

Biochemical evaluation of amniotic fluid content is often used to monitor fetal secretory and excretory functions. It is known that alcohol freely passes through the placenta and enters the fetal tissues. The study was designed to investigate whether alcohol use during pregnancy affects amniotic fluid steroid and peptide hormone levels. Five alcohol users who drank between 40 and 45 drinks per month and consumed approximately 1 oz. of alcohol per day from beer drinking participated in the study. Thirteen controls with no history of alcohol use including essential and non-essential drugs were selected for the study. The final selection of participants was made among those who delivered male offsprings. Amniotic fluid was aspirated between 16 and 20 weeks of gestation by amniocentesis and an aliquot was used to assay steroid hormones (4-androstenedione [-4-AD], testosterone [T], estradiol [E2], dehydroepiandrosterone sulfate [DHEA-S]), and peptide hormones (FSH and LH). Birth weights, placental weights and gestation age were recorded at birth. The results showed that -4-AD, T and E2 levels were significantly decreased (P less than 0.01) in alcohol users; DHEA-S, FSH and LH levels were unaffected. Birth weights were significantly decreased (P less than 0.05) in alcohol users, the placental weights and gestation age were not affected. We conclude that alcohol passes through the placenta and affects fetal testes, capacity to synthesize steroids and the effect appears to be direct and not via the hypothalamic-hypophyseal axis.

Adult↗
PubMed1990

Structure and tissue-specific regulation of genes encoding barley (1----3, 1----4)-beta-glucan endohydrolases.

Two genes encode (1----3, 1----4)-beta-glucan 4-glucanohydrolase (EC 3.2.1.73) isoenzymes in barley. A gene for isoenzyme EI has been isolated from a barley genomic library and the nucleotide sequence of a 4643 bp fragment determined. The gene is located on barley chromosome 5 while the gene for (1----3, 1----4)-beta-glucanase isoenzyme EII is carried on chromosome 1. The isoenzyme EI gene contains a single 2514 bp intron that is inserted in codon 25 of a sequence encoding a signal peptide of 28 amino acids. The coding region of the mature enzyme is characterized by a high G+C content, which results from an extreme bias towards the use of these nucleotides in the wobble base position of codons. Determination of the nucleotide sequence of the gene has enabled the complete primary structure of the enzyme to be deduced: isoenzyme EI shows 92% positional identity with the primary sequence of (1----3, 1----4)-beta-glucanase isoenzyme EII at both the nucleotide and amino acid level. However, the nucleotide sequences of the two genes diverge markedly in their 3' untranslated regions. Expression sites of the two genes were defined by Northern analysis using oligonucleotide probes specific for these 3' untranslated regions and by amplifying specific cDNAs through the polymerase chain reaction. In the tissues examined, transcription of the isoenzyme EII gene is restricted to the aleurone layer of germinated grain. In contrast, the gene for isoenzyme EI is transcribed at relatively high levels in young leaves, but also in the scutellum and aleurone of germinated grain.

Amino Acid Sequence↗
PubMed1990

Specific localization of lectins in boar and bull spermatozoa.

The roles that complex carbohydrates play in gamete recognition and fertilization are well-documented. This study was designed to identify and map sites of N-linked oligosaccharides in boar and bull sperm. Plant lectins, conjugated with FITC, RITC and gold particles, were used as probes for specific sugar moieties in sperm membranes. Results showed strong labeling of sperm heads by most lectins. However, lectins with specificities for mannosyl, glucosyl, and sialic acid were predominantly distributed over the sperm acrosomal region. Lectins specific for fucosyl residues predominantly stained the postacrosomal regions of both boar and bull sperm. Lectin gold studies revealed that mannosyl and galactosyl-linked residues occupied the acrosomal membrane and plasma membrane in the postacrosomal region, but not the nucleus or nuclear membrane. The cytoplasmic droplet, middle piece and flagellum of boar and bull sperm were moderately stained by lectins. The microquantitative analysis confirmed the fluorescence data. The presence of fucosyl residues predominantly in the postacrosomal regions lends credence to the suggestion that glycoproteins rich in fucosyl-like residues may be a universal carbohydrate moiety involved in recognition processes in mammalian fertilization.

Animals↗
PubMed1989

Facilitory role of thyroid hormone in vitamin A uptake in the rat testes.

The inter-relationship of hormones and retinol (vit. A) metabolism is under investigation in our laboratory. The investigation is designed to study the role of thyroid hormone (tetraiodothyronine, T4) in the uptake of vit. A in various rat tissues. Adult male thyroidectomized (Tx) rats, partially vit. A deficient, were administered intragastrically tritium-labeled vit. A. Twenty-four hours later, the level of radioactivity was measured in the blood plasma, liver, kidneys, testes and urine collected for 24 hrs. The data showed that in Tx rats, there was a significant decrease (P less than .01) in the level of radioactivity in the kidneys, testes and urine; in blood plasma and the liver, there was a significant increase (P less than .01). In Tx rats, treatment with T4 restored 50-70% of the radioactivity lost in the kidneys, testes and urine. The endogenous vit. A level in Tx rats treated without and with T4 followed essentially the same pattern. The capacity of cellular retinol binding protein (CRBP) to bind exogenously added vit. A was examined. The data showed a decrease in the binding capacity of CRBP in Tx rats. We conclude that T4 facilitates the uptake of vit. A in the target tissues by regulating CRBP synthesis or degradation.

Animals↗
PubMed1981

Blood hormone profiles in prostate cancer patients in high-risk and low-risk populations.

Epidemiologic data reveal that the incidence rate of prostate gland carcinoma among the black population in the United States (US) is several times higher than among Nigerians. A collaborative study between the two countries was undertaken, and blood hormone (testosterone [T], dihydrotestosterone [DHT], estrone [E1], estradiol [E2], and prolactin [P1]), total acid phosphatase (TP), and prostatic acid phosphatase (PAP) profiles in the two population groups were compared. In the US groups (patients and controls) there were significantly higher levels of T (P less than 0.01) and E1 (P less than 0.05) compared with the Nigerians. Also, the US patients had significantly higher levels of T (P less than 0.05) and E1 (P less than 0.01) compared with their matched controls. In the Nigerians T but not E1 levels were significantly lower (P less than 0.05) in patients compared with controls. DHT, E2, and P1 were not significantly different in patients and controls between and within the populations. Nigerian patients had higher levels (P less than 0.001) of TP and PAP compared with US patients. It is concluded that differences in blood hormone profiles in the two population groups are based on factors other than the genetic makeup of the populations.

Acid Phosphatase↗
PubMed1981

Regional lung function evaluation with nitrogen-13.

Regional ventilation and perfusion studies are routinely performed with molecular nitrogen-13 (a short-lived positron emitter), a multicrystal positron camera, and a computer. These studies have the advantage of viewing with equal sensitivity all sections of the lung simultaneously. Nitrogen-13 is less soluble than xenon in blood and therefore allows more accurate ventilation imaging. The short half-life of the radiopharmaceutical allows simultaneous ventilation and perfusion scintigraphy of the lung. Unlike other imaging techniques in which the residual radioactivity persists in the lung for hours, nitrogen-13 is rapidly cleared allowing repetitive imaging. Ventilation and perfusion studies are part of the routine preoperative evaluation for lung cancer resection or for bullectomy in patients with chronic obstructive pulmonary disease and for assessment of pulmonary emboli in the presence of chronic obstructive disease.

Adult↗
PubMed1981

Regional edema formation in isolated perfused dog lungs.

Studies using gravimetric analysis of lungs of frozen animals have suggested that the differences in pulmonary microvascular pressure between non-dependent and dependent lung do not influence the formation of regional pulmonary edema. We wondered if the inability to detect variation in regional extravascular lung water (EVLW) was due to the slow freezing process and, therefore, reassessed the distribution of EVLW in vertically suspended isolated perfused dog lungs with a radioisotopic technique that does not require freezing. Total lung water (TLW), blood or intravascular lung water (IVLW), and EVLW were measured in absolute quantities using a positron camera and the positron-emitting isotopes C15O as a blood label and H2(15)O as a total lung water label. Mean isotopic TLW in 17 lungs that were normal or moderately edematous (wet:dry ratio < 7) was 142 +/- 9 (SE) ml compared to the gravimetric estimate of 148 +/- 7 ml (r = 0.92) and isotopic EVLW was 64 +/- 6 ml compared to the gravimetric estimate of 70 +/- 6 ml (r = 0.8). Analysis of the distribution of regional isotopically measured EVLW in the 17 lungs in various states of spontaneous edema formation revealed a small non-dependent to dependent, gravity-related increase in percent regional EVLW compared to percent regional TLW, which did not vary with the degree of edema in the lung. Serial measurements of absolute regional EVLW in four lungs during spontaneously developing edema also failed to show a disproportionate increase in accumulation of EVLW in any lung zone. Thus, despite the wide variation in microvascular hydrostatic pressure between top and bottom of the vertical isolated lung, edema formation seems to be uniform.

Animals↗
PubMed1980

Variation of ethinylestradiol blood levels among healthy women using oral contraceptives.

Data concerning ethinylestradiol (EE) blood levels among 93 healthy women using oral contraceptives are presented. Seventy-two per cent of the observed variation in EE blood levels was unexplainable on the basis of time since ingestion of the last oral contraceptive, day of menstrual cycle, race, age, weight, height, blood pressure, cigarette consumption, alcohol consumption, diurnal variation, or lifetime use of oral contraceptives.

Adult↗
PubMed1978

N13-N2(1).

13N when coupled with a positron camera allows excellent quantification and imaging of regional lung function. The studies can be readily repeated since the half-life of the 13N is uncer 10 min and the radiation dose to the patient with each study is low. The very low solubility of 13N not only enhances lung imaging but reduces total body radiation by remaining confined to the lung.

Adolescent↗
PubMed1977

Inhalation imaging with oxygen-15 labeled carbon dioxide for detection and quantitation of left-to-right shunts.

Quantitation of left-to-right shunts was determined noninvasively from the pulmonary clearance pattern of inhaled 15oxygen-labeled carbon dioxide (C15O2). After a single breath inhalation of C15O2, counts over the lungs were obtained from sequential 0.5 sec positron camera images. In 21 patients without left-to-right shunts, counts declined exponentially due to the washout of C15O2 by the pulmonary blood flow. In 22 patients with left-to-right shunts, this monoexponential pulmonary clearance pattern was interrupted by an abnormal upward deviation, indicating tracer recirculation through the shunt to the lungs. Following surgical shung closure in 10 patients, pulmonary C15O2 clearance patterns became normal in nine and showed a small residual left-to-right shunt in one. Shunt size was derived from the ratio of the height of the recirculation curve to the height of the initial inhalation peak. These values significantly correlated with shunt size as determined by oximetry (r = 0.83).

Adolescent↗
PubMed1976

Retinyl palmitate, a major retinyl ester in rat testis seminiferous tubules. II. The Sertoli cell, site of retinol esterification.

The study was designed to 1) isolate and quantitate retinyl esters normally present in the testis seminiferous tubules (ST) and 2) determine whether the Sertoli (SE) cells in the ST have the enzyme system necessary to esterify retinol. In the first study testes from normal adult male rats were removed, the ST were isolated mechanically and retinol was extracted and separated into free and retinyl esters in a prestandardized alumina column. The fraction containing retinyl esters was hydrolyzed, and the fatty acid composition was determined gas chromatographically. The results showed that retinyl palmitate was the major retinyl ester in the testis ST constituting almost 55% of the total esters. In the second study adult male rats were given Busulfan (1,4, dimethylsulfonoxybutane) intraperitoneally twice six weeks apart. At the end of six weeks following injection, the testes from a few animals were examined histologically, and the results showed that Busulfan treatment destroyed the germinal epithelium completely but had no effect on the structural integrity of the SE cells. Labeled retinol (free) mixed in rat albumin solution was injected intratesticularly (in vivo study) or incubated (in vitro study) with ST which had been isolated from the testes of rats treated with Busulfan. The results of the studies indicate that labeled retinol (free) was converted to retinyl esters in the ST. Since the ratio of conversion of free retinol (labeled) to retinyl esters remained constant in the treated ST (which contained only Sertoli cells, the germinal epithelium having been destroyed) and in the control ST (which contained both Sertoli cells and germinal epithelium), we conclude that the Sertoli cells are the site of retinol esterification in the testis ST.

Animals↗
PubMed1975

A competitive protein binding radioassay for 17alpha-ethynylestradiol in human plasma.

A competitive protein binding radioassay system using a rabbit uterine cytosol preparation for the measurement of ethynylestradiol [EE2e] in human plasma has been developed. Sephadex LH-20 column chromatography is used for the separation of the estrogens prior to assay. EE2 levels were measured in 23 normotensive subjects on contraceptive pills containing either 50 mug of EE2 or mestranol. The EE2 values ranged from 144 to 248 pg with a mean of 211 pg (S.D. +/- 37.94). The method is sensitive enough to detect 25 pg of EE2 in plasma. The intra- and inter-assay coefficients of variation were 7.54% and 10.75%, respectively. Water blanks and plasma blanks from subjects not on pills gave negligible readings for EE2.

Animals↗
PubMed1975

Strength of pulmonary vascular response to regional alveolar hypoxia.

Regional alveolar hypoxia in the lung induces regional pulmonary vasoconstriction which diverts blood flow from the hypoxic area. However, the predominant determinant of the distribution of perfusion in the normal erect lung is gravity so that more perfusion occurs at the base than at the apex. To determine the strength of the regional alveolar hypoxic response in diverting flow with or against the gravity gradient a divided tracheal cannula was placed in anesthetized dogs and unilateral alveolar hypoxia created by venilating one lung with nitrogen while ventilating the other lung with oxygen to preserve normal systemic oxygentation. Scintigrams of the distribution of perfusion obtained with intravenous 13-N and the MGH positron camera revealed a 34 and 32 per cent decrease in perfusion to the hypoxic lung in the supine and erect positions and a 26 per cent decrease in the decubitus position with the hypoxic lung dependent (P equal to 0.94 from supine shift), indicating nearly equal vasoconstriction with shift of perfusion away from the hypoxic lung in all positions. Analysis of regional shifts in perfusion revealed an equal vasoconstrictor response from apex to base in the supine position but a greater response in the lower lung zones in the erect position where perfusion was also greatest.

Animals↗