Biomedical subjects

S Bhatt

Publications and source records attributed to S Bhatt.

At least 19 recordsLinked to original sources

PubMed2006

Rare Robertsonian translocations and meiotic behaviour: sperm FISH analysis of t(13;15) and t(14;15) translocations: a case report.

t(13;15) and t(14;15) are two rare Robertsonian translocations. Meiotic segregation was studied in four males heterozygous for the rare Robertsonian translocations t(13;15) and t(14;15). Both locus-specific probes (LSPs) and whole chromosome painting (WCP) probes, specific to chromosomes 13, 14 and 15, were used in this study. The number of spermatozoa scored for each carrier ranged from 891 to 5000. The frequencies of normal and balanced sperm resulting from the alternate mode of segregation ranged from 77.6 to 92.8%, confirming the prevalence of alternate segregation over other segregation modes in all Robertsonian translocations. The incidences of unbalanced complements ranged from 6.7 to 20.4%, with a significant excess of disomy rates over the complementary frequencies of nullisomy. This variability might reflect differences in the location of breakpoints in translocated chromosomes, leading to the variable production of unbalanced gametes and the variable alterations of semen parameters in Robertsonian translocation carriers.

Adult↗

PubMed2006

Doppler evaluation of erectile dysfunction - part 1.

Erectile dysfunction (ED) is the consistent inability to achieve and maintain an erection sufficient for satisfactory sexual activity. Erectile dysfunction affects as many as 30 million men in America, with an increasing prevalence with age. Erectile dysfunction is secondary to organic, psychogenic and combined causes. The first part of this review article describes the guidelines for evaluation and treatment plans for men with ED. It also describes the normal sonographic anatomy of the penis, sonographic technique for evaluation of ED and the normal phases of erection.

Adult↗

PubMed2006

Doppler evaluation of erectile dysfunction - part 2.

Doppler evaluation in erectile dysfunction (ED) has a significant role in determining the cause of ED. The advantages of penile Doppler and pharmacologic duplex ultrasonography include objective, minimally invasive evaluation of penile hemodynamics at a relatively low cost. Arteriogenic ED may be secondary to peripheral vascular disease and diabetes, or may be seen in association with coronary artery disease. Various parameters, such as diameter of the cavernosal artery, peak systolic flow velocity, degree of arterial dilatation and acceleration time, have been suggested for the diagnosis of arteriogenic ED, but peak systolic flow velocity is the most accurate indicator of arterial disease. This second part of the review article describes the various causes of ED and the interpretation and evaluation of color flow Doppler examination in ED.

Erectile Dysfunction↗

PubMed2006

Meiotic segregation of rare Robertsonian translocations: sperm analysis of three t(14q;22q) cases.

BACKGROUND: The t(14;22) remains one of the rare Robertsonian translocations observed in human, with an occurrence estimated at 1.2%. Three cases of rare Robertsonian translocation t(14;22) were investigated for meiotic segregation in sperm samples from male carriers using the fluorescent in situ hybridization (FISH) procedure. The three carriers included two men with an abnormal semen analysis and one with normal semen parameters. METHODS: Both locus-specific probes and whole-chromosome painting probes, specific for chromosomes 14 and 22, were used in this study. The number of spermatozoa scored for each probe set ranged from 3279 to 10,024. RESULTS: In the three carriers, similar frequencies, ranging from 78.53 to 81.76%, were found for normal and balanced spermatozoa resulting from alternate segregation. The total proportion of unbalanced spermatozoa resulting from adjacent modes of segregation ranged from 17.59 to 20.94%. CONCLUSION: This finding confirmed the predominance of alternate segregation over other segregation types in all Robertsonian translocations and indicates a higher production of imbalances in the t(14;22) than in most of the Robertsonian translocations previously analysed. This could be related to the variable location of breakpoints in Robertsonian translocations. This breakpoint diversity could also play a role in the differences in reproductive status observed in male carriers of Robertsonian translocations.

Adult↗

PubMed2005

Potentiating role of interleukin-1beta (IL-1beta) and IL-1beta type 1 receptors in the medial hypothalamus in defensive rage behavior in the cat.

Recently, this laboratory provided evidence that interleukin-1beta (IL-1beta), an immune and brain-derived cytokine, microinjected into the medial hypothalamus, potentiates defensive rage behavior in the cat elicited from the midbrain periaqueductal gray (PAG), and that such effects are blocked by a 5-HT2 receptor antagonist. Since this finding represents the first time that a brain cytokine has been shown to affect defensive rage behavior, the present study replicated and extended these findings by documenting the specific potentiating role played by IL-1beta Type 1 receptor (IL-1RI), and the anatomical relationship between IL-1beta and 5-HT2 receptors in the medial hypothalamus. IL-1beta (10 ng) microinjected into the medial hypothalamus induced two separate phases of facilitation, one at 60 min and another at 180 min, post-injection. In turn, these effects were blocked with pretreatment of the selective IL-1 Type I receptor antagonist (IL-1ra) (10 ng), demonstrating the selectivity of the effects of IL-1beta on medial hypothalamic neurons upon PAG-elicited defensive rage behavior. The next stage of the study utilized immunohistochemical methods to demonstrate that IL-1beta and 5-HT2 receptors were present on the same neurons within regions of the medial hypothalamus where IL-1beta and the IL-1beta receptor antagonists were administered. This provided anatomical evidence suggesting a relationship between IL-1RI and 5-HT2 receptors in the medial hypothalamus that is consistent with the previous pharmacological observations in our laboratory. The overall findings show that activation of IL-1RI in the medial hypothalamus potentiates defensive rage behavior in the cat and that these effects may also be linked to the presence of 5-HT2 receptors on the same groups of neurons in this region of hypothalamus.

Aggression↗

PubMed2005

Cytokine modulation of defensive rage behavior in the cat: role of GABAA and interleukin-2 receptors in the medial hypothalamus.

Defensive rage behavior is a form of aggressive behavior occurring in nature in response to a threatening stimulus. It is also elicited by stimulation of the medial hypothalamus and midbrain periaqueductal gray (PAG) and mediated through specific neurotransmitter-receptor mechanisms within these regions. Since interleukin (IL)-2 modulates the release of neurotransmitters linked to aggression and rage, we sought to determine whether IL-2 microinjected into the medial hypothalamus would modulate defensive rage. Microinjections of relatively low doses of IL-2 into the medial hypothalamus significantly suppressed defensive rage elicited from the PAG in a dose-dependent manner and in the absence of signs of sickness behavior. Pre-treatment with an antibody directed against IL-2Ralpha or a GABA(A) receptor antagonist blocked IL-2's suppressive effects upon defensive rage. Since the suppression of defensive rage is also mediated by 5-HT(1) receptors in the medial hypothalamus, a 5-HT(1) antagonist was microinjected into this region as a pretreatment for IL-2; however, it did not block IL-2's suppressive effects. Immunocytochemical data provided anatomical support for these findings by revealing extensive labeling of IL-2Ralpha on neurons in the medial hypothalamus. IL-2 microinjected into the medial hypothalamus did not modulate predatory attack elicited from the lateral hypothalamus. In summary, we provide evidence for a novel role for IL-2 in the medial hypothalamus as a potent suppressor of defensive rage behavior. These effects are mediated through an IL-2-GABA(A) receptor mechanism.

Aggression↗

PubMed2004

Amygdaloid kindled seizures induce weight gain that reflects left hemisphere dominance in rats.

The present study sought to determine the effects of kindled seizures generated from the left and right amygdala upon weight gain in rat. Seventy-five female Sprague-Dawley rats were implanted with electrodes in basal amygdala of the left and right hemispheres. A kindling paradigm was employed in which electrical stimulation was applied once per day for 30 days after Stage 5 seizures. An electrode was implanted into the basal amygdala of the control rats but no stimulation was applied. All rats were weighed daily during the course of the experiment and changes in weight during this period were recorded for all rats. The results demonstrated that kindling from either the left or right amygdala induced significant increases in weight gain relative to the control rats. However, kindling from the left basal amygdala induced increases in body weight that were four times greater than control rats and two times greater than the rats kindled from the right side of the basal amygdala. Likewise, serum leptin levels, which were highly correlated with weight gain, also showed significantly greater increases in left amygdaloid kindled rats relative to rats kindled from the right amygdala and control rats. These findings demonstrate that basal amygdaloid kindling induces significant increases in weight gain and that the magnitude of these effects is linked to the dominance of the left hemisphere.

Amygdala↗

PubMed2003

Differential modulation of feline defensive rage behavior in the medial hypothalamus by 5-HT1A and 5-HT2 receptors.

Previous studies have established that the expression of defensive rage behavior in the cat is mediated over reciprocal pathways that link the medial hypothalamus and the dorsolateral quadrant of the midbrain periaqueductal gray matter (PAG). The present study was designed to determine the roles played by 5-HT(1A) and 5-HT(2C) receptors in the medial hypothalamus on the expression of defensive rage behavior elicited from electrical stimulation of the PAG. Monopolar stimulating electrodes were placed in the midbrain PAG from which defensive rage behavior could be elicited by electrical stimulation. During the course of this study, defensive rage was determined by measuring the latency of the "hissing" component of this behavior. Cannula-electrodes were implanted into sites within the medial hypothalamus from which defensive rage behavior could also be elicited by electrical stimulation in order that serotonergic compounds could be microinjected into behaviorally identifiable regions of the hypothalamus at a later time. Microinjections of the 5-HT(1A) receptor agonist 8-OHDPAT (0.1, 1.0 and 3.0 nmol) into the medial hypothalamus suppressed PAG-elicited hissing in a dose-dependent manner. Administration of the 5-HT(1A) antagonist p-MPPI (3.0 nmol) blocked the suppressive effects of 8-OHDPAT upon hissing. The suppressive effects of 8-OHDPAT were specific to defensive rage behavior because this drug (3 nmol) facilitated quiet biting attack. Microinjections of the 5-HT(2C) receptor agonist (+/-)-DOI hydrochloride into the medial hypothalamus (0.5, 1.0, and 3.0 nmol) facilitated the occurrence of PAG-elicited hissing in a dose-dependent manner. In turn, these facilitating effects were blocked by pretreatment with the selective 5-HT(2) antagonist, LY-53,857, which was microinjected into the same medial hypothalamic site. The findings of this study provide evidence that activation of 5-HT(1A) and 5-HT(2) receptors within the medial hypothalamus exert differential modulatory effects upon defensive rage behavior elicited from the midbrain PAG of the cat.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed2003

Interleukin-1 beta in the hypothalamus potentiates feline defensive rage: role of serotonin-2 receptors.

The neurochemistry of aggression and rage has largely focused on the roles played by neurotransmitters and their receptor mechanisms. In contrast, little attention has been given to the possible functions of other substances. Interleukin-1beta is an immune and brain-derived cytokine that is present in the hypothalamus. Functionally, interleukin-1 has been shown to induce the release of serotonin (5-HT), a neurotransmitter known to potently affect aggression and rage behavior. Thus, the goal of the present study was to test the hypothesis that interleukin-1beta in the medial hypothalamus could modulate defensive rage behavior in the cat. In the first experiment, electrical stimulation of sites in the medial hypothalamus from which defensive rage could be elicited and where microinjections of specific compounds were later placed, facilitated defensive rage elicited from the periaqueductal gray (PAG), thus demonstrating the functional relationship between these two regions. In the second experiment, microinjections of relatively low doses of interleukin-1beta into the medial hypothalamus potentiated defensive rage behavior elicited from the midbrain periaqueductal gray in a dose-related manner. In the third experiment, pretreatment with a selective 5-HT2 receptor antagonist, LY-53857, blocked the facilitating effects of interleukin-1beta upon defensive rage. These findings reveal for the first time that brain cytokines can dramatically alter aggressive behavior. In particular, interleukin-1beta in the medial hypothalamus potentiates defensive rage behavior elicited from the periaqueductal gray in the cat, and the potentiating effects of interleukin-1beta on this form of emotional behavior are mediated via a 5-HT2 receptor mechanism.

Animals↗

PubMed2003

Factors influencing the care-seeking behaviour of chest symptomatics: a community-based study involving rural and urban population in Tamil Nadu, South India.

Our aim was to identify the factors that influence the care-seeking behaviour of chest symptomatics in urban and rural areas in South India. We conducted in-depth interviews with 649 participants: 80% of 310 urban residents and 63% of 339 rural people had sought care (P < 0.01), 93% within 1 month of onset of symptoms. Private health care facilities were the first and preferred point of contact for 57% of urban and 48% of rural participants; the major reasons were proximity to residence and their perception that good-quality care would be available there. Symptomatics who did not seek care attributed their inaction to insufficient severity of symptoms (51%), unaffordability (46%) and lack of time due to work pressures (25%). Socio-economic factors such as literacy and family income significantly influenced care-seeking behaviour. Our results indicate that most chest symptomatics seek care promptly; their initial response is to go to the nearest private health care facility, shifting to another if they are dissatisfied. Fifty per cent of the participants who did not seek care felt that their symptoms were not severe.

Adolescent↗

PubMed2003

Synthesis and biological evaluation of N-substituted alpha-amino acids from 4-hydroxy coumarins.

The synthesis of a series of N-(methylene-4-oxo coumarinyl) carbamates by the condensation of various carbamates with 4-hydroxy coumarins in the presence of triethylorthoformate was undertaken to obtain the the title compounds in 50-55% yields. Preliminary data shows that only few molecules are active against B. subtilis, S. aureus, E. coli and P. aeruginosa at minium inhibitory concentrations (MIC) of 100, 300, 500 micrograms/ml compared to streptomycin (CAS 57-92-1) and kanamycin (CAS 59-01-8). The alkyl groups present in the benzenoid part and the higher amino acid residues like 3a, 3c, 5a and 5b were found to be more active in the title compounds (i.e. 2d and 2e).

4-Hydroxycoumarins↗

PubMed1997

Deletions of 20p12 in Alagille syndrome: frequency and molecular characterization.

Alagille syndrome is an autosomal dominant disorder comprising cholestasis (associated with intrahepatic bile duct paucity), characteristic facial appearance, and cardiac, ocular and skeletal defects. Multiple patients have been reported with deletions or translocation involving 20p11.23-p12, providing evidence for the localization of the disease gene to this region. Fifty-six Alagille syndrome patients have been studied by cytogenetic and/or molecular analysis to determine the frequency of detectable abnormalities of 20p12. Two of fifty-six patients studied by cytogenetic analysis had abnormalities: an interstitial deletion in one patient and a translocation in another. Of forty-five patients studied by molecular analysis, three were found to have deletions of 20p, including the two patients identified with cytogenetic abnormalities. Molecular and molecular cytogenetic (FISH) analysis of the translocation (46,XX,t(2;20)(q21.3p12)) demonstrated a deletion at the translocation breakpoint. The deletions identified in the three patients are overlapping, contributing to the delineation of an Alagille syndrome critical region within 20p12. This region lies between markers D20S41 and D20S162. The frequency of detectable cytogenetic abnormalities of 20p12 in this group of Alagille patients is 2/56 (3.6%), and the frequency of molecular deletions is 3/45 (6.7%). This is considerably lower than the frequency of deletions observed in contiguous gene deletion syndromes suggesting that Alagille syndrome may be caused by the alteration of a single gene.

Adolescent↗

PubMed1995

Transient leukemia with trisomy 21: description of a case and review of the literature.

Transient myeloproliferative disease (TMD) is often associated with a trisomy 21 cell line, but it is not always associated with clinical signs of Down syndrome. We report on a phenotypically normal newborn boy who presented with a high white blood cell count, undifferentiated blasts, and cutaneous leukemic infiltrates and compare this patient with the literature on TMD and trisomy 21. Chromosome analysis of bone marrow, and subsequently of skin fibroblasts, documented constitutional mosaicism for trisomy 21. A decrease in the frequency of blast cells paralleled a decrease in cells demonstrating trisomy 21 in hematopoietic tissues, and a complete clinical recovery was seen without the use of chemotherapy. Recognition of this transient form of congenital leukemia is important to prevent the unnecessary use of toxic chemotherapeutic agents in such patients.

Bone Marrow↗

PubMed1995

Pulmonary consequences of carbon dioxide insufflation for laparoscopic cholecystectomies.

Twenty patients having laparoscopic cholecystectomies were studied for changes in thoracic and lung compliance at 5, 10 and 15 mmHg of intra-abdominal pressure. Fifteen mmHg of intra-abdominal pressure decreased the thoracic and the lung static compliance by 49 and 39% respectively. This was unaffected by the degree of head elevation. During the procedure the end-tidal carbon dioxide increased by a mean of 1.6 kPa at 1 h and 2.0 kPa at 2 h. This did not appear to be related to either the mean intra-abdominal pressure or the total volume of carbon dioxide insufflated. The physiological changes and implications for anaesthetic practice are considered.

Abdomen↗

PubMed1994

Microcephalic osteodysplastic dysplasia.

We present two patients with a distinct facial phenotype, short stature, brachydactyly, clubfoot deformities, cataracts, microcephaly, and normal intelligence. Similar radiographic abnormalities of the spine, long bones, hands, and feet were noted. These patients are similar to 2 males previously described by Saul and Wilson [1990: Am J Med Genet 35:388-393]. These 4 patients appear to have a unique skeletal dysplasia characterized by microcephaly, distinct facial phenotype, multisystem abnormalities, and short stature of postnatal onset.

Abnormalities, Multiple↗

PubMed1994

Chrysosporium tropicum as a probable cause of mycosis of poultry in India.

Chrysosporium tropicum was isolated from comb lesions in two different breeds of chickens in India and subcultures were shown to be pathogenic when inoculated onto prepared skin of guinea pigs. This report provides additional evidence to consider Ch. tropicum as a pathogenic fungus and a probable cause of a dermatomycosis in chickens.

Animals↗

PubMed1993

Extraskeletal mesenchymal chondrosarcoma of the orbit.

Mesenchymal chondrosarcoma, an uncommon lesion of bone and extraskeletal tissue, is rare in the orbit. A case of extraskeletal mesenchymal chondrosarcoma of the orbit in a 28-year-old woman presenting with proptosis and diminution of vision in the left eye is reported. Histologically, the tumor showed areas of undifferentiated mesenchymal cells with islands of cartilage. Immunohistochemical analysis for S-100 protein showed focal positivity in chondroid areas. The eye was preserved and the patient has good vision after 2 years of follow-up.

Adult↗

PubMed1993

Alterations in repair of alkylating agent-induced DNA damage in polyamine-depleted human cells.

Treatment of HeLa cells with the polyamine biosynthesis inhibitors difluoromethylornithine (DFMO) and/or methylglyoxal bis(guanylhydrazone) (MGBG) results in marked depression in levels of the cellular polyamines putrescine, spermidine and spermine. Cells in this polyamine-depleted state exhibited increased sensitivity to monofunctional alkylating agents, manifested as decreased cloning ability and retardation of the DNA excision repair process. DFMO treatment did not alter the initial level of interaction of radiolabeled alkylating agent with cellular DNA, but combined treatment with DFMO and MGBG reduced covalent binding, probably through effects on cell cycling. Polyamine supplementation had no effects on initial yield of DNA single-strand breaks in drug-treated cells. The repair defect appeared similar to that observed previously in polyamine-depleted cells following X-irradiation and UV irradiation, namely retarded sealing of DNA strand breaks. It was not possible to reverse the effects of these inhibitors by short periods of polyamine loading, despite the fact that all three polyamines could be restored to near-normal levels. These findings provide the first demonstration of altered response of polyamine-depleted cells to monofunctional alkylating agents and contribute to our understanding of altered responses of polyamine-depleted cancer cells to a variety of DNA-reactive chemotherapeutic drugs.

Alkylating Agents↗