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Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 235 records · Page 13Linked to original sources
PubMed1994

Cerebrospinal fluid dopamine in HIV-1 infection.

BACKGROUND: Increasing evidence suggests significant involvement of the basal ganglia in patients with HIV-1 infection. OBJECTIVE: To study the effect of HIV-1 infection on cerebrospinal fluid (CSF) dopamine levels. DESIGN: CSF dopamine levels were measured by high-performance liquid chromatography. SETTING: A university-based outpatient clinic in south Florida involved in clinical AIDS research. SUBJECTS: Twenty-two subjects were enrolled in a prospective, longitudinal study of the neurological complications of AIDS. Five subjects were HIV-seronegative, but at risk for HIV-1 infection, 11 were HIV-1-seropositive without neurological disease and six had HIV-1-related neurological disease. RESULTS: The CSF dopamine mean values were significantly lower in the HIV-1-seropositive group with (P < 0.0001) or without (P < 0.0001) neurological disease than in the HIV-seronegative group. There was a very strong correlation between CD4 lymphocyte counts and CSF dopamine levels (P = 0.004) in the neurologically symptomatic group (P = 0.0008), but not in the other two groups. CONCLUSION: HIV-1 infection appears to have an effect on the central nervous system dopaminergic systems, as reflected in levels of CSF dopamine.

Adult↗
PubMed1994

Massive upper gastrointestinal bleeding due to Candida esophagitis.

Significant hemorrhage from esophageal candidiasis in patients without a major bleeding diathesis is extremely uncommon. A case of recurrent, severe upper gastrointestinal bleeding due to hemorrhagic candidal esophagitis in a man with renal failure is described. Dysphagia, odynophagia, and retrosternal chest discomfort were all absent. Oral thrush was present only at the outset. Standard therapy for massive bleeding with blood products alone was not successful. Intravenous amphotericin eventually resulted in resolution.

Acute Kidney Injury↗
PubMed1994

Brainstem auditory evoked response changes following electro-acupuncture therapy in chronic pain patients.

Brainstem auditory evoked responses were recorded in 17 patients with chronic pain who had been given electro-acupuncture therapy. The absolute peak latencies of waves I to V, and interpeak latencies and amplitudes of waves I and V were analysed before electro-acupuncture and compared with values obtained during electro-acupuncture and 5 min after its termination after one, five and 10 sittings. At these sittings the intensity of pain was recorded with the help of a 100 mm visual analogue scale. Each patient had 10 sittings given on alternate days. The absolute peak latencies of waves I, II, and III were delayed significantly (p < 0.05) after 5 and 10 sittings and amplitudes of wave V decreased significantly (p < 0.05) after 5 and 10 sittings. Visual analogue scores also decreased significantly (p < 0.01) during these sittings. It was established that before and after 10 sittings of electro-acupuncture, there was a significant positive correlation between visual analogue scores and the amplitude of wave V (p < 0.01). There was a negative correlation between visual analogue scores and absolute peak latencies of wave III at 1, 5 and 10 sittings, suggesting that there is a definite interaction between the electro-acupuncture neural mechanism and the generators of brainstem auditory evoked responses in the lower brainstem.

Adolescent↗
PubMed1994

Recovery from pre-operative sedation with clonidine--brain stem auditory evoked response.

In a randomised double-blind study, 34 elderly patients (ASA grades 1-2) underwent elective intra-ocular surgery. Patients were allocated randomly to two groups to receive oral clonidine 300 micrograms or oral diazepam 10 mg 2 h before surgery. Facial block and retrobulbar block were given at 2 h after premedication. Anaesthetic recovery was assessed using a clinical recovery score (at 0, 30, 60 and 120 min after arrival in the recovery room) and brain stem auditory evoked potential responses (BAER) (immediately after operation and at 120 min after operation). In both the groups the clinical recovery scores decreased significantly at 30 and 60 min following recovery (p < 0.01). At 120 min this score returned to the pre-operative value in the clonidine group, but in the diazepam group there was a significant difference between the 2h value and pre-operative value (p < 0.05). In the clonidine group there was no significant rise in the interpeak latencies and absolute peak latencies of brain stem auditory evoked responses recorded immediately after operation and 120 min after operation. In the diazepam group, there was a significant rise in the interpeak latencies immediately after operation and 120 min after operation and a rise in absolute peak latencies (p < 0.05) immediately after operation. In the clonidine group there was a reduction (p < 0.05) in amplitude of wave V at immediately after operation. We conclude that clonidine 300 micrograms orally before surgery does not delay recovery.

Aged↗
PubMed1994

Human immunodeficiency virus type 1 Rev-responsive element RNA binds to host cell-specific proteins.

RNase protection-gel retention studies show human host cell-specific ribonucleoprotein complexes with human immunodeficiency virus type 1 Rev-responsive element (RRE) RNA. Nuclear proteins from rodent or murine cells appear to lack the ability to form these complexes. Human-mouse somatic cell hybrids retaining a single human chromosome, either 6 or 12, form the RRE-nuclear-protein complexes. One of the complexes requires the entire RRE RNA, while the other needs RRE RNA stem-loops 1 and 2 only. Two major proteins with molecular masses of 120 and 62 kDa specifically bind to RRE RNA. Rodent cells (CHO) either lack or contain small amounts of these RRE-binding proteins.

Animals↗
PubMed1994

Multiple carpometacarpal dislocations.

We present a case of dislocations of the carpometacarpal joints without associated fractures. Although carpometacarpal injuries are relatively uncommon, it is rare for multiple carpometacarpal dislocations to occur without associated fractures. The injury is difficult to diagnose because of swelling of the hand. A lateral radiograph of the wrist has been found to be mandatory to its precise diagnosis if suspected. In the case presented here early diagnosis and closed manipulation in the accident and emergency (A&E) department resulted in a good outcome.

Adult↗
PubMed1994

Familial atrioventricular septal defect: possible genetic mechanisms.

BACKGROUND: Most non-chromosomal congenital heart defects are thought to be caused by the interaction of genetic factors involving multiple genes and environmental factors. Families that have several affected members have been reported, however, which suggests that a single autosomal dominant or recessive gene may cause the cardiac defects. A family in which atrioventricular septal defect seemed to be a single gene disorder is reported. OBSERVATIONS: A family in which the mother and her two daughters from different fathers had atrioventricular septal defect not associated with trisomy 21 is reported. CONCLUSIONS: This family raises the possibility that cytoplasmic or mitochondrial inheritance may be involved in the causation of atrioventricular septal defects. The available data from pedigrees from other cases of familial atrioventricular septal defect do not support this genetic mechanism, but suggest that there is a subgroup without trisomy 21 that has a single gene disorder.

Adolescent↗
PubMed1994

Effects of TGF-beta and TNF-alpha on procoagulant and fibrinolytic pathways of human tracheal epithelial cells.

The epithelial lining of the airways is subject to injury through several processes, including infections, bronchiolitis, and fume exposures. Because airway fibrin deposition influences the course of local injury, we examined how two inflammatory cytokines influenced fibrin formation and clearance in human tracheal epithelial cells (TEC). TEC were treated with transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha). TNF-alpha increased release of tissue factor (TF)-related procoagulant activity that, through generation of factor Xa, promotes assembly of the prothrombinase complex at the cell surface. Fibrinolytic activity was plasminogen dependent and due to both urokinase (uPA) and tissue plasminogen activator (tPA). The cells expressed plasminogen activator inhibitor 1 (PAI-1), but relatively little PAI-2. Depression of fibrinolysis by TGF-beta correlated with increased PAI-1. Conversely, TNF-alpha increased plasminogen activator (PA) activity due to increased uPA. Fibrinolytic activity was inhibited by actinomycin D and cyclohexamide, but changes in mRNAs for uPA, tPA, PAI-1, and TF by either cytokine were not appreciable. PAI-2 mRNA was not found. The data indicate that TGF-beta decreases the fibrinolytic capacity of TEC, suggesting that this cytokine promotes fibrin retention. TNF-alpha increases expression of both procoagulant and fibrinolytic activities; this differential regulation could favor both pericellular fibrin formation and dissolution.

Base Sequence↗
PubMed1994

Latex antigens induce IgE and eosinophils in mice.

Hypersensitivity to latex proteins has been reported with increasing frequency in recent years. Elevated levels of latex specific IgE have been detected in the majority of these patients. Severe anaphylaxis and death resulting from latex exposure has also been reported. Nevertheless, the immune mechanism of latex allergy is not fully understood. In this report, we describe a model of latex allergy developed in mice exposed to latex proteins. Animals exposed to latex proteins demonstrated enhanced levels of total IgE, peripheral blood and lung eosinophilia, and elevated levels of serum IL-4 and IL-5. mRNA transcripts of IL-4 and IL-5, but not IFN-gamma, could be demonstrated in spleen lymphocytes. Antibodies to latex belonging to all IgG subclasses were detected in the sera of mice exposed to latex antigens. The histology of the lung showed non-necrotizing granulomas and extensive interstitial chronic inflammatory infiltrates, particularly around bronchioles and small blood vessels. Although this model of latex allergy demonstrates a heterogeneous immunological response, the CD4-positive Th2 cell-mediated response predominated.

Animals↗
PubMed1994

Topical atropine and timolol therapy in failed retinal detachment surgery.

We conducted a double-blind randomized prospective study to evaluate the efficacy of topical timolol alone and topical timolol and atropine combined in cases of operated failed retinal detachment surgery cases in which no apparent open break explained the surgical failure. In both groups with and without proliferative vitreoretinopathy no statistically significant difference in retinal reattachment was found.

Administration, Topical↗
PubMed1994

Pathways of fibrin turnover in lavage of premature baboons with hyperoxic lung injury.

Lung injury induced by 100% O2 over 6 days is characterized by markedly less alveolar fibrin and rare hyaline membranes in premature versus adult baboons. To determine the mechanism(s) underlying alveolar fibrin deposition in the evolution of hyaline membrane disease (HMD) through diffuse alveolar damage (DAD) and bronchopulmonary dysplasia (BPD), we measured procoagulant and fibrinolytic activities in lung lavage of premature baboons with HMD, those treated with 100% O2 for 6 days (DAD) or for 7 days followed by 14 days 80% O2 (BPD). Lavage procoagulant activity, mainly due to tissue factor associated with Factor VII, was increased by hyperoxia. Plasminogen-dependent fibrinolytic activity, due to both tissue plasminogen activator and urokinase, was stable or increased after hyperoxia. Plasminogen activator inhibitor 1 (PAI-1) was detectable in lavage of animals with HMD but not those with evolving DAD or BPD. Antiplasmin activity was stable or decreased. Although plasminogen was undetectable in lavage, D-dimer was increased in lavage of the groups exposed to hyperoxia versus HMD. The defect in plasminogen activator activity in lavage fluids of adult baboons with DAD induced by O2 does not occur in premature baboons with HMD, evolving DAD, or BPD. Expression of fibrinolytic activity in the lower respiratory tract of premature baboons is dependent on local access to plasminogen, which is present in relatively low concentrations in plasma of these animals.

Age Factors↗
PubMed1994

SLE in Indian men: analysis of the clinical and laboratory features with a review of the literature.

Data on the clinical and laboratory profile of 39 male lupus patients has been analysed. An attempt has been made to (1) delineate the pattern of SLE in Indian males, (2) compare it with that reported in the world literature, (3) find out differences, if any, between male children and adults with the disease, and (4) compare it with our previously published data on Indian females with SLE. Several important points were brought out in this study. First, SLE in Indian males has an earlier age of disease onset, a higher incidence of mucocutaneous and renal involvement and a lower incidence of neuropsychiatric, gastrointestinal and hematological disease in comparison to those published from the developed countries. Second, leucopenia and lymphopenia, a reflection of disease severity, occur significantly more in male children compared with adults. Thrombocytopenia is exclusively noted in adult males and virtually non-existent in children. Third, male patients overall have a less severe form of the disease in comparison with their female counterpart, as was evident by significantly less patients with hypocomplementemia, diffuse proliferative lupus nephritis and psychosis. Finally, a higher frequency of infection, particularly tuberculosis, was seen in male patients, which was the cause of death in some.

Adolescent↗
PubMed1994

Influence of hypophysectomy on renal proteoglycans and their modulation by insulin-like growth factor-I and its receptor.

Hypophysectomy leads to growth retardation of the animals, which is believed to be related to the deficiency of certain growth factors influencing the metabolism and synthesis of glycoproteins. Conceivably, the extracellular matrix proteins (ECM) are also affected, in particular the sulfated proteoglycans (PGs). In this study, we investigated the status of the ECM proteins and sulfated PGs, and the expression and de novo synthesis of insulin-like growth factor-I (IGF-I) receptor (IGF-IR) in hypophysectomized (Hx) rats. The studies were extended to ascertain the effect of IGF-I on the de novo synthesis of glomerular ECM glycoproteins in Hx rats. An organ perfusion system was used in which isolated rat kidneys were radiolabeled with either [35S]sulfate or [35S]methionine, after which IGF-IR and ECM macromolecules were isolated and characterized by biochemical and tissue autoradiographic procedures. Hypophysectomy resulted in a fall in IGF-I levels in serum and isolated renal glomeruli. Reduced synthesis of ECM proteins, i.e. type IV collagen, laminin, and sulfated PGs, and reduced synthesis and mRNA expression of IGF-IR were observed in the glomeruli of the Hx rats. Tissue autoradiographic studies revealed a reduced grain density (concentration of radiation) over various cell types of the glomerulus. After inclusion of IGF-I in the perfusion medium not only was synthesis restored to normal in Hx rats, but it far exceeded the control basal values in the intact animals. Under the influence of IGF-I, the magnitude of increased synthesis of the ECM proteins, in particular the sulfated PGs, was highly accentuated in the kidneys of the Hx group compared to the controls. Also, a remarkably increased [35S]sulfate incorporation was observed in the glomerular mesangial cells. The analysis of IGF-IR by specific binding studies revealed a decreased concentration of the receptors, but an increased IGF-I-binding affinity, the latter of which probably contributed to the IGF-I-induced accentuated synthesis of renal glomerular PGs in the Hx group.

Animals↗
PubMed1994

Interleukin-1 regulates corticosterone secretion from the rat adrenal gland through a catecholamine-dependent and prostaglandin E2-independent mechanism.

Studies from this and other laboratories have shown that interleukin-1 alpha (IL-1 alpha) stimulates corticosterone and prostaglandin (PG) release from primary cultures of rat adrenal cells. A previous report from our laboratory (1) indicated involvement of the alpha-adrenergic system in IL-1 alpha-stimulated corticosterone secretion from primary cultures of rat adrenal cells. The present experiments were conducted to determine the role of catecholamines and eicosanoids in IL-1-stimulated corticosterone release from primary rat adrenal cells. Primary adrenal cells were incubated for 24 h at 37 C with IL-1 alpha (10 nM), medium, or the appropriate agonist. After incubation, the supernatant was removed and assayed for epinephrine, prostaglandin E2 (PGE2), and corticosterone concentrations. At this time, untreated adrenal cells were fixed for immunohistochemical staining with a specific antirat tyrosine hydroxylase antibody. The results indicate that the primary adrenal cells contained 3.1 +/- 0.45% tyrosine hydroxylase-positive cells. On the ultrastructural level, the chromaffin cells were found to be in direct cellular contact with cortical cells. IL-1 alpha significantly increased (P < 0.05) epinephrine, PGE2, and corticosterone levels above those in medium-treated controls from primary adrenal cells. In the presence of the alpha-adrenergic antagonist phentolamine (10 microM), IL-1 alpha-stimulated (P < 0.05) corticosterone release was inhibited, whereas IL-1 alpha-induced PGE2 release was not affected. Conversely, the presence of the cyclooxygenase inhibitor indomethacin (10 microM) significantly inhibited IL-1 alpha-induced PGE2 secretion without altering the effect of IL-1 alpha on corticosterone release. Inhibitors of the 5-lipoxygenase system (10 microM CGS 8518) and the lipoxygenase and cytochrome P450 monooxygenase systems (10 microM nordihydroguaiaretic acid) did not effect IL-1 alpha-induced corticosterone or PGE2 release. These observations indicate that IL-1 alpha stimulates corticosterone release through an alpha-adrenergic mechanism that is independent of PGE2 release from primary rat adrenal cells.

Adrenal Glands↗
PubMed1994

Differential growth factor-induced modulation of proteoglycans synthesized by normal human renal versus cyst-derived cells.

In polycystic kidney disease (PKD), there is an insiduous enlargement of the kidneys and dilation of the renal tubules associated with extracellular matrix (ECM) alterations. The latter include thickening of tubular basement membrane and decreased synthesis of sulfated proteoglycan (PG). Because PKD is believed to be a disorder of cell growth and deranged ECM metabolism, it is conceivable that the formation of cystic tubules may be modulated by certain growth factors (GF) that influence the synthesis of ECM glycoproteins. In this study, the effect of various GF, i.e., epidermal, hepatocyte (HGF) and transforming (TGF), and triiodothyronine on the PG synthesized by normal human kidney (NK) epithelial cells and cells derived from cysts of patients with autosomal dominant PKD (ADPKD) was assessed. (35S) sulfate incorporation studies revealed that, among various GF, HGF and TGF-beta 1 had the maximal stimulatory effect on the synthesis of PG extracted from ADPKD cells. A minimal increase in the PG synthesis was observed in NK cells; however, PG synthesized under the influence of HGF or TGF-beta 1 were of relatively higher molecular weight, with a shift of K(av) from 0.28 to 0.12, as ascertained by Sepharose-6B chromatography. PG synthesized by ADPKD cells had a K(av) = 0.18, and it did not change with the GF treatment. The charge-density characteristics of PG of ADPKD cells were relatively lower than those of NK cells, and they were unaffected by HGF or TGF-beta 1 treatment. Interestingly, both the HGF and TGF-beta 1 significantly affected posttranslational modifications of PG.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗