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Biomedical subjects

S Solomon

Publications and source records attributed to S Solomon.

At least 73 records · Page 4Linked to original sources
PubMed2000

Skeletal development in the meat-type chicken.

1. This study ascertained how bone of modern meat-type chickens develops under typical commercial conditions and compares development with that in genetic precursor stock. 2. A modern fast-growing selected strain and a slower-growing control strain were used. Birds were weighed weekly. A random sample was taken from each population at a range of ages up to 39 d. 3. A tibiotarsus from each bird was X-rayed and its dimensions and estimated resistance to bending were determined. Cortical bone samples were ashed to measure total mineral, calcium and phosphorus content. Cortical samples were also taken for porosity assessment. 4. As expected, the selected strain grew faster and heavier than the control strain. Despite this, both strains demonstrated similar periods of rapid bone formation (days 4 to 18) and mineralisation (days 4 to 11), and achieved similar estimates of resistance to bending. 5. However, cortical bone of the selected strain was less well mineralised and more porous than that of the control strain and showed a significant increase in the molar Ca:P ratios above the expected range of values during the first 2 to 3 weeks of life. 6. Despite production of bones with the correct dimensions for load support, the relatively poor density and mineral content of bone in the selected strain is likely to reduce effective breaking strength of the tibiotarsus. Possible reasons may be either inadequate dietary supply of Ca and P or impaired utilisation of the minerals due to a rapid growth rate or genetic factors.

Animals↗
PubMed2000

Feasibility of ablating normal renal parenchyma by interstitial photon radiation energy: study in a canine model.

BACKGROUND AND PURPOSE: A miniature photon radiosurgery system (PRS) has been described as an alternative to surgical resection and external-beam radiation for tumors and may now offer an alternative for ablation of renal lesions. We evaluated the feasibility of ablation by PRS in a normal parenchyma canine model. MATERIALS AND METHODS: Twelve mongrel dogs were used in this survival study. In the left and right kidneys of each animal, a peripheral lesion and central-hilar lesion, respectively, were induced with PRS. The probes were placed in the renal parenchyma, and local radiation of 15 Gy at a radius of 1.3 cm was delivered over 10 minutes. Serum electrolytes were measured serially. Computed tomography scans were obtained, and the animals were sacrificed for pathologic correlation. In a separate study, the liver received three additional treatments of 10 to 20 minutes of radiation. RESULTS: Eleven dogs survived this 6-month study and were sacrificed as scheduled. One animal expired after 2 weeks from radiation-induced fulminant hepatic failure with normal renal function. No other complications were observed. The average lesion size was 2.5 cm in diameter. Histologic analysis confirmed coagulative necrosis with sharp demarcation from the surrounding parenchyma. CONCLUSION: Preliminary studies demonstrate the feasibility of PRS ablation of the renal parenchyma. Further tumor model testing will be important to determine the ultimate efficacy of local photon radiation energy.

Animals↗
PubMed2000

Oral lesions and conditions associated with human immunodeficiency virus infection in 300 south Indian patients.

BACKGROUND: Human immunodeficiency virus infection/acquired immunodeficiency syndrome (HIV/AIDS) is a major health problem in India. The National AIDS Control Organisation (NACO) of India reports a seropositivity of 25.03 per thousand for the whole country, as of October 1999. In spite of this high prevalence there are very few reports of oral lesions and conditions in Indian HIV/AIDS patients, which are important in early diagnosis and management of these patients. OBJECTIVE AND SETTING: The present report describes the oral lesions in 300 HIV positive symptomatic patients presenting to us at RAGAS-YRG CARE, a non-governmental organisation in Chennai, South India, over a period of 9 months in 1998. METHOD: Lesions were diagnosed on clinical appearance using international criteria. RESULTS: Of the 300 patients 89% had acquired the infection through heterosexual contact. There were 205 males and 95 females, aged from 7 months to 72 years. Forty-seven percent of the patients were in the age group 21-30 years. CD4 counts were ascertained for 105 patients, 64 (62%) had CD4 counts < or = 200. A total of 217 (72%) of the 300 patients had some oral lesion when examined. Gingivitis (47%) and pseudomembranous candidiasis (33%) were the most common oral lesions. The other oral lesions seen were oral mucosal pigmentation (23%), erythematous candidiasis (14%), periodontitis (9%), angular cheilitis (8%), oral ulcers (3%), oral hairy leukoplakia (3%), hyperplastic candidiasis (1%), oral submucous fibrosis (2%) and one case of leukoplakia. CONCLUSIONS: Oral lesions occur commonly in HIV infection. A comprehensive oral examination may not only suggest HIV disease but may also be useful in monitoring the disease progression. This is a cost-effective procedure, which may be useful in screening large populations in developing countries like India.

AIDS-Related Opportunistic Infections↗
PubMed2000

Corticotropin releasing hormone and proopiomelanocortin involvement in the cutaneous response to stress.

The skin is a known target organ for the proopiomelanocortin (POMC)-derived neuropeptides alpha-melanocyte stimulating hormone (alpha-MSH), beta-endorphin, and ACTH and also a source of these peptides. Skin expression levels of the POMC gene and POMC/corticotropin releasing hormone (CRH) peptides are not static but are determined by such factors as the physiological changes associated with hair cycle (highest in anagen phase), ultraviolet radiation (UVR) exposure, immune cytokine release, or the presence of cutaneous pathology. Among the cytokines, the proinflammatory interleukin-1 produces important upregulation of cutaneous levels of POMC mRNA, POMC peptides, and MSH receptors; UVR also stimulates expression of all the components of the CRH/POMC system including expression of the corresponding receptors. Molecular characterization of the cutaneous POMC gene shows mRNA forms similar to those found in the pituitary, which are expressed together with shorter variants. The receptors for POMC peptides expressed in the skin are functional and include MC1, MC5 and mu-opiate, although most predominant are those of the MC1 class recognizing MSH and ACTH. Receptors for CRH are also present in the skin. Because expression of, for example, the MC1 receptor is stimulated in a similar dose-dependent manner by UVR, cytokines, MSH peptides or melanin precursors, actions of the ligand peptides represent a stochastic (predictable) nonspecific response to environmental/endogenous stresses. The powerful effects of POMC peptides and probably CRH on the skin pigmentary, immune, and adnexal systems are consistent with stress-neutralizing activity addressed at maintaining skin integrity to restrict disruptions of internal homeostasis. Hence, cutaneous expression of the CRH/POMC system is highly organized, encoding mediators and receptors similar to the hypothalamic-pituitary-adrenal (HPA) axis. This CRH/POMC skin system appears to generate a function analogous to the HPA axis, that in the skin is expressed as a highly localized response which neutralizes noxious stimuli and attendant immune reactions.

Animals↗
PubMed2000

Marriage, monogamy and HIV: a profile of HIV-infected women in south India.

A retrospective study was conducted on 134 HIV-infected females evaluated at an HIV/AIDS centre in south India to characterize their sociodemographics, HIV risk factors and initial clinical presentations. The mean age was 29 years; 81% were housewives; 95% were currently or previously married; 89% reported heterosexual sex as their only HIV risk factor; and 88% reported a history of monogamy. The majority were of reproductive age, thus the potential for vertical transmission of HIV and devastating impacts on families is alarming. Nearly half of these women initially presented asymptomatically implying that partner recruitment can enable early HIV detection. Single partner heterosexual sex with their husband was the only HIV risk factor for the majority of women. HIV prevention and intervention strategies need to focus on married, monogamous Indian women whose self-perception of HIV risk may be low, but whose risk is inextricably linked to the behaviour of their husbands.

Adolescent↗
PubMed2000

Identification of Pneumocystis carinii in induced sputum of AIDS patients in Chennai (Madras).

Induced sputum samples were collected from 32 AIDS patients with respiratory ailments. Pneumcystis carinii was demonstrated in 9 out of 32 AIDS cases by Indirect Immunofluorescence technique (HF). Four cases were positive by all the three techniques namely Giemsa staining, Toluidine blue staining and IIF, three were positive by both toluidine blue and IIF, and two were positive only by IIF. Among other microbial pathogens, acid fast bacilli was demonstrated in all the P carinii positive cases and Candida albicans in 53% AIDS cases from the induced sputum sample.

AIDS-Related Opportunistic Infections↗
PubMed2000

Antiretroviral drugs in the treatment of people living with human immunodeficiency virus: experience in a south Indian tertiary referral centre.

OBJECTIVE: A decrease in the number of new acquired immunodeficiency syndrome (AIDS) cases and AIDS--related deaths was seen in developed countries since 1996 due to the use of new combination of antiretroviral drugs. This retrospective study discusses the use of antiretroviral drugs in the treatment of people living with human immunodeficiency virus (HIV) in a developing country setting. METHODS: A retrospective case note analysis was done of patients receiving antiretroviral therapy at YRG Centre for AIDS Research and Education between Aug. 1996 and Feb. 1999. Out of 936 persons with HIV treated at this centre, 6.1% of the patients were prescribed three groups of drugs: Group A was the combination of the reverse transcriptase inhibitors (nRTI) zidovudine 600 mg daily and lamivudine 300 mg daily, Group B was the combination of zidovudine 600 mg daily, lamivudine 300 mg daily with protease inhibitor (PI) ritonavir 1200 mg daily and Group C was the combination of zidovudine 600 mg daily and lamivudine 300 mg daily with indinavir 2400 mg daily. Twenty HIV positive pregnant women were given zidovudine 500 mg daily during the third trimester (Group D) to reduce the vertical transmission of HIV. RESULTS: The mean CD4 gain was 188.0 cells/micro litre in Group A, 118.8 cell/microlitre in Group B and 223.3 cells/microlitre in Group C with a mean duration of 4.3, 3.1 and 3.5 months respectively. Many patients stopped antiretroviral drugs due to high cost of therapy. CONCLUSION: Hence, physicians should prescribe antiretroviral drugs only after ensuring that the patients can afford and will comply with a longterm treatment. Prescribing guidelines should be available to those working in this field and should be adhered to so that emergence of resistant strains could be prevented.

Adult↗
PubMed2000

Immune recovery vitritis presenting as panuveitis following therapy with protease inhibitors.

Immune reconstitution in acquired immunodeficiency syndrome (AIDS) patients on highly active anti-retroviral therapy (HAART) with cytomegalovirus (CMV) retinitis manifested as posterior segment intraocular inflammation has been reported. We report an adult HIV-positive Indian male with clinically inactive CMV retinitis who developed panuveitis with hypopyon. This was related to immune recovery mediated by combination anti-retroviral treatment, including protease inhibitors.

AIDS-Related Opportunistic Infections↗
PubMed1999

On the role of the weather in the deaths of R. F. Scott and his companions.

Robert Falcon Scott and his companions reached the South Pole in January of 1912, only to die on their return journey at a remote site on the Ross Ice Shelf, about 170 miles from their base camp on the coast. Numerous contributing causes for their deaths have been proposed, but it has been assumed that the cold temperatures they reported encountering on the Ross Ice Shelf, near 82-80 degrees S during their northward trek toward safety, were not unusual. The weather in the region where they perished on their unassisted trek by foot from the Pole remained undocumented for more than half a century, but it has now been monitored by multiple automated weather stations for more than a decade. The data recorded by Scott and his men from late February to March 19, 1912, display daily temperature minima that were on average 10 to 20 degrees F below those obtained in the same region and season since routine modern observations began in 1985. Only 1 year in the available 15 years of measurements from the location where Scott and his men perished displays persistent cold temperatures at this time of year close to those reported in 1912. These remarkably cold temperatures likely contributed substantially to the exhaustion and frostbite Scott and his companions endured, and their deaths were therefore due, at least in part, to the unusual weather conditions they endured during their cold march across the Ross Ice Shelf of Antarctica.

Journal Article↗
PubMed1999

POMC-derived peptides and their biological action.

It has long been known that a large number of POMC-related peptides are found in skin. In this introduction I describe the formation of POMC-derived peptides in various tissues to indicate that processing is largely tissue-dependent. I focus on the peptides from the N-terminal fragment, such as gamma-MSH, ACTH and alpha-MSH, and beta-lipopropin as well as beta-endorphin. I touch on the factors that control the synthesis of the various peptides, which are now numerous and varied, and again are tissue specific. The biologic activity of the peptides generated from POMC are described in relation to their possible action in skin. In addition, I describe a new class of peptides induced in skin following injury and which are of great interest.

Adrenocorticotropic Hormone↗
PubMed1999

Neutrophil defensins induce histamine secretion from mast cells: mechanisms of action.

Defensins are endogenous antimicrobial peptides stored in neutrophil granules. Here we report that a panel of defensins from human, rat, guinea pig, and rabbit neutrophils all have histamine-releasing activity, degranulating rat peritoneal mast cells with EC50 ranging from 70 to 2500 nM, and between 45 and 60% of the total histamine released. The EC50 for defensin-induced histamine secretion correlates with their net basic charge at neutral pH. There is no correlation between histamine release and antimicrobial potency. Degranulation induced by defensins has characteristics similar to those of activation by substance P. The maximum percent histamine release is achieved in <10 s, and it can be markedly inhibited by pertussis toxin (100 ng/ml) and by pretreatment of mast cells with neuraminidase. These properties differ from those for degranulation induced by IgE-dependent Ag stimulation and by the calcium ionophore A23187. GTPase activity, a measure of G protein activation, was induced in a membrane fraction from mast cells following treatment with defensin. Thus, neutrophil defensins are potent mast cell secretagogues that act in a manner similar to substance P and 48/80, through a rapid G protein-dependent response that is mechanistically distinct from Ag/IgE-dependent mast cell activation. Defensins may provide important pathways for communication between neutrophils and mast cells in defenses against microbial agents and in acute inflammatory responses.

Amino Acid Sequence↗
PubMed1999

Familial dilated cardiomyopathy locus maps to chromosome 2q31.

BACKGROUND: Inherited gene defects are an important cause of dilated cardiomyopathy. Although the chromosome locations of some defects and 1 disease gene (actin) have been identified, the genetic etiologies of most cases of familial dilated cardiomyopathy remain unknown. METHODS AND RESULTS: We clinically evaluated 3 generations of a kindred with autosomal dominant transmission of dilated cardiomyopathy. Nine surviving and affected individuals had early-onset disease (ventricular chamber dilation during the teenage years and congestive heart failure during the third decade of life). The disease was nonpenetrant in 2 obligate carriers. To identify the causal gene defect, linkage studies were performed. A new dilated cardiomyopathy locus was identified on chromosome 2 between loci GCG and D2S72 (maximum logarithm of odds [LOD] score=4.86 at theta=0). Because the massive gene encoding titin, a cytoskeletal muscle protein, resides in this disease interval, sequences encoding 900 amino acid residues of the cardiac-specific (N2-B) domain were analyzed. Five sequence variants were identified, but none segregated with disease in this family. CONCLUSIONS: A dilated cardiomyopathy locus (designated CMD1G) is located on chromosome 2q31 and causes early-onset congestive heart failure. Although titin remains an intriguing candidate gene for this disorder, a disease-causing mutation is not present in its cardiac-specific N2-B domain.

Adolescent↗
PubMed1999

Stereotypes and terror management: evidence that mortality salience enhances stereotypic thinking and preferences.

If stereotypes function to protect people against death-related concerns, then mortality salience should increase stereotypic thinking and preferences for stereotype-confirming individuals. Study 1 demonstrated that mortality salience increased stereotyping of Germans. In Study 2, it increased participants' tendency to generate more explanations for stereotype-inconsistent than stereotype-consistent gender role behavior. In Study 3, mortality salience increased participants' liking for a stereotype-consistent African American and decreased their liking for a stereotype-inconsistent African American; control participants exhibited the opposite preference. Study 4 replicated this pattern with evaluations of stereotype-confirming or stereotype-disconfirming men and women. Study 5 showed that, among participants high in need for closure, mortality salience led to decreased liking for a stereotype-inconsistent gay man.

Adult↗
PubMed1999

Death, sex, love, and neuroticism: why is sex such a problem?

Terror management theory posits that sex is a ubiquitous human problem because the creaturely aspects of sex make apparent our animal nature, which reminds us of our vulnerability and mortality. People minimize this threat by investing in the symbolic meaning offered by the cultural worldview. Because people high in neuroticism have difficulty finding or sustaining meaning, sex is a particular problem for them. In Study 1, mortality salience caused high-neuroticism participants to find the physical aspects of sex less appealing. Study 2 revealed that for such individuals thoughts of physical sex increase the accessibility of death-related thoughts. This finding was replicated in Study 3, which also showed that providing meaning by associating sex with love reduces the accessibility of death-related thoughts in response to thoughts of physical sex. These findings provide insight into why people high in neuroticism have conflicting thoughts about sexuality and why sexuality is so often regulated and romanticized.

Adult↗
PubMed1999

A dual-process model of defense against conscious and unconscious death-related thoughts: an extension of terror management theory.

Distinct defensive processes are activated by conscious and nonconscious but accessible thoughts of death. Proximal defenses, which entail suppressing death-related thoughts or pushing the problem of death into the distant future by denying one's vulnerability, are rational, threat-focused, and activated when thoughts of death are in current focal attention. Distal terror management defenses, which entail maintaining self-esteem and faith in one's cultural worldview, function to control the potential for anxiety that results from knowing that death is inevitable. These defenses are experiential, are not related to the problem of death in any semantic or logical way, and are increasingly activated as the accessibility of death-related thoughts increases, up to the point at which such thoughts enter consciousness and proximal threat-focused defenses are initiated. Experimental evidence for this analysis is presented.

Behavior Therapy↗