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Biomedical subjects

A Thakur

Publications and source records attributed to A Thakur.

At least 37 records · Page 2Linked to original sources
PubMed2001

Surgical treatment of severe colonic inertia with restorative proctocolectomy.

Patients with severe constipation due to colonic inertia who remain symptomatic after extensive medical therapy or partial colonic resection have occasionally been treated with ileostomy as a last resort. The hospital records of five patients with persistent symptomatic idiopathic colonic inertia were reviewed. Each of the patients had undergone extensive medical management, and eventually four underwent one or more colonic resections to relieve the recurrent abdominal distention and pain. Three of the patients eventually received a distal ileostomy, which functioned well. Anorectal manometric studies were within normal range for each of the five patients. Restorative proctocolectomy (J pouch) was therefore performed for each. With a mean follow-up of 42 months after restorative proctocolectomy each of the five patients was relieved of constipation and small bowel distention. The average number of bowel movements per 24 hours at 6 months was 4.8. All patients were able to discriminate flatus from stool, could hold back for up to 1.5 hours after the initial urge to defecate, and had total daytime continence. Each returned to work or school within 3 months, and each reported greater satisfaction with bowel function than with the ileostomy. Restorative proctocolectomy with a J pouch provides a satisfactory option for the management of patients with persistent abdominal distention and pain due to idiopathic colonic inertia.

Adolescent↗
PubMed2001

Rapid tranquilization with olanzapine in acute psychosis: a case series.

Acute, high-dose loading strategies (rapid neuroleptization) with the first-generation antipsychotics administered orally or parenterally, alone or combined with benzodiazepines, have been a commonly used treatment paradigm for controlling acutely agitated psychotic patients. The rationale was to achieve high plasma levels of drug within a shorter time period, resulting in rapid symptom mitigation. However, studies have shown that rapid neuroleptization with first-generation antipsychotics is associated with a greater incidence of side effects. To our knowledge, loading strategies with second-generation antipsychotics have not been investigated, primarily owing to a need for dose titration. Olanzapine, a second-generation antipsychotic, is well tolerated in doses ranging from 5 to 20 mg. The objective of this report was to determine experience with the use of up to 20 mg of an oral loading dose of olanzapine administered within 4 hours in the treatment of patients early in an acute psychotic phase of their illness. In the reported case series of 57 patients, olanzapine initiated at 15 to 20 mg/day was a safe and effective medication for rapidly calming the agitation of acutely agitated psychotic patients (rapid tranquilization). Furthermore, dose reduction over 2 to 3 weeks was achieved in a number of patients without appreciable loss of efficacy.

Acute Disease↗
PubMed2000

Ontogeny of insulin-like growth factor 1 in a rabbit model of growth retardation.

Many cases of intrauterine growth retardation (IUGR) result from placental insufficiency, but the molecular signals accompanying this event are unknown. Insulin-like growth factor 1 (IGF-1) is a potent mitogen for fetal tissues and is lowered in the serum of human infants with IUGR. The rabbit provides an optimal model for the study of IUGR based on fetal position. To determine if IGF-1 expression is altered in the growth-retarded fetus, this naturally occurring rabbit model of IUGR was used. Four fetal rabbit pairs were harvested on Days 21, 23, 25, 27, 29, and 31 of their normal 31-day gestation; they were identified based on uterine position as normal or growth retarded. Fetal weight was recorded and the serum, amniotic fluid, liver, kidney, and small intestine (SI) were collected. The SI was divided into three equal segments: proximal, middle, and distal. Reverse transcription polymerase chain reaction (RT-PCR) was used to measure IGF-1/beta-actin mRNA densitometric band ratios in all tissues. Radioimmunoassay (RIA) was used to measure IGF-1 protein levels in the serum and amniotic fluid. Statistical analysis was performed using ANOVA and the paired Student's t test. Weights were decreased in fetuses with IUGR at all time points (P < 0.05), further validating this rabbit model in the study of IUGR. Liver, proximal, and distal SI IGF-1 mRNA decreased during late gestation (P < 0.01). Kidney IGF-1 mRNA increased throughout late gestation (P < 0.01). Compared with their normal counterparts, fetuses with IUGR had a trend toward decreased IGF-1 mRNA in the kidney, liver, and SI at all time points, reaching significance in the liver on Day 27 (P = 0.002). Serum IGF-1 decreased throughout gestation in all fetuses (P < 0.05). Compared with normal fetuses, fetuses with IUGR had lower serum IGF-1 at all time points, reaching significance at Day 27 (P = 0.02). Amniotic fluid IGF-1 was lower in fetuses with IUGR than in normal fetuses, though not quite reaching significance. Compared with normal fetuses, growth-retarded fetal rabbits trend toward depressed liver, kidney, and intestinal expression of IGF-1 mRNA and lower serum and amniotic fluid IGF-1 protein. Serum IGF-1 levels correlate with fetal weight change. Further studies and potential manipulation of fetal IGF-1 are warranted to investigate potential prenatal intervention in the treatment of IUGR.

Amniotic Fluid↗
PubMed2000

The outcome of research training during surgical residency.

BACKGROUND/PURPOSE: Graduates of a university surgical residency program were surveyed to identify the timing of specialty selection and the impact that studying in a research laboratory had on subsequent acceptance into a fellowship program. METHODS: Between 1975 and 1990, 86 residents completed general surgery training at UCLA Medical Center. A survey was sent to all graduates to determine the focus of their previous laboratory research and when they selected their eventual surgical specialty. Responses were received from 67 of the 86 graduates (78%). RESULTS: Forty-eight of the sixty-seven respondents (72%) took one or more years of surgical research during residency. Postresidency fellowship training was selected by 55 of 67 (82%); 50 applied to fewer than five programs; 49 of 55 (89%) received one of their top three choices. Twenty-seven of the sixty-seven residents pursued an academic career (40%). Residents who performed at least 2 years of research were more likely to become academicians (53%) than residents who did 1 year or less of research (22%). Only 39 of 67 residents (58%) had selected a specialty after 2 years of clinical training; 28 more made the selection after the third clinical year. All residents interested in cardiac surgery (n = 18) or plastic surgery (n = 4) prior to research were accepted into fellowships in those specialities, whereas only 37% of those who had an interest in other fields pursued the same specialty (P < 0.0001). Residents performing research in general surgery (n = 9), surgical oncology (n = 18), cardiac surgery (n = 14), and plastic surgery (n = 3) were more likely to practice in that specialty than those doing research in other specialty laboratories. CONCLUSIONS: General surgery residents performing research in a specialty laboratory are likely to pursue fellowship training relating to that field. Those who select a career in cardiac or plastic surgery prior to research are most likely to enter into these fields as their eventual specialty. Residents who perform 2 or more years of laboratory research publish more papers and often pursue an academic career.

General Surgery↗
PubMed2000

Contact lens wear alters the production of certain inflammatory mediators in tears.

Contact lens wear has been associated with an increased risk of corneal infection and/or inflammation. We studied the hypothesis that contact lens wear alters the number of polymorphonuclear leukocytes (PMNs) on the cornea during sleep and the levels of inflammatory mediators in the tear film. Three groups of subjects were analysed: a non-contact lens wearing group (NCLW), non-adapted (neophyte) contact lens wearers (NACLW) who wore lenses during sleep for the first time in this study and adapted contact lens wearers (ACLW) who normally wore lenses on a daily wear schedule. Ocular PMNs were collected by a non-contact irrigation technique and their numbers counted after staining. Tears were collected from each group and analysed using ELISAs for the presence of the PMN chemoattractants IL-8 and LTB(4)and the cytokines IL-1beta, IL-6 and GM-CSF. Corneal irrigation data demonstrated significantly higher numbers of PMNs from NACLW (P<0.05) compared to the other groups. ACLW showed significantly fewer PMNs (P =0.03) compared to NCLW group. The NACLW group had significantly lower concentrations (P<0. 05) of IL-8, LTB(4)and IL-6 in their tears after 8 hr of sleep compared to the other groups. The ACLW group had significantly (P<0. 05) higher levels of IL-8 at most time points compared to the other two groups. The levels of the chemoattractants IL-8 and LTB(4)in tears were inversely related to the numbers of PMNs from the corneal surface and the chemotaxis of PMNs in vitro. During one night sleep in contact lenses the numbers of PMNs and the concentration of certain inflammatory mediators are significantly altered compared to no lens wear. However, this alteration changes from NACLW to ACLW. This may have effects on the ability of the eye to defend itself during contact lens wear.

Adult↗
PubMed2000

Comparison of loop versus end ileostomy for fecal diversion after restorative proctocolectomy for ulcerative colitis.

BACKGROUND: The goal of this study was to compare the benefits versus complications of temporary loop ileostomies and end ileostomies in a consecutive series of patients undergoing colectomy and ileal pouch-anal anastomosis for ulcerative colitis. STUDY DESIGN: A retrospective review was performed of all patients undergoing restorative proctocolectomy with diverting ileostomy for ulcerative colitis at the UCLA Medical Center during a 4-year period. An end ileostomy (EI) was used for 38 patients and a loop ileostomy (LI) for 39. All patients had a J pouch, with all EI patients having a hand-sewn ileoanal anastomosis, and 33 LI patients having a double-stapled anal anastomosis. EI closure was performed through a laparotomy, and LI closure was performed through a periileostomy incision. RESULTS: The mean operative time for EI closure was 157 minutes, and for LI closure was 103 minutes. The wound infection rate after EI closure was 5.3% and after LI was 10.3%. For EI patients, 2 of 38 patients required reoperation, compared with 5 of 39 for LI. The mean hospital stay after EI closure was 6.7 days, and after LI closure was 7.1 days. Peristomal skin irritation was more severe, more prolonged, and occurred in more than twice as many LI as EI patients. Home ostomy nurse care was necessary for a mean of two visits for EI patients and five visits for LI patients. The cost ofostomy supplies and care was more than double for LI patients compared with those with EI. Patient satisfaction and ability to resume physical and social activities early after ileostomy construction were much more favorable for EI than LI patients. CONCLUSIONS: The benefit of shorter operating time for LI closure compared with EI closure is often outweighed by the complications and costs of LI stomal care and patient dissatisfaction. EI should be considered more frequently for temporary ileal diversion after restorative proctocolectomy.

Adolescent↗
PubMed2000

KC production in the cornea in response to Pseudomonas aeruginosa challenge.

Pseudomonas aeruginosa can cause ulcerative bacterial keratitis. A feature of keratitis is the rapid infiltration of the avascular corneal stroma by neutrophils. KC is a potent neutrophil chemokine. The present study used a mouse model of ocular infection to assess the relationship between KC and inflammation in the cornea in response to challenge with a strain of P. aeruginosa causing keratitis. Low levels of KC mRNA and protein were detected by in situ hybridization and ELISA, respectively, in unchallenged corneas. Dramatically increased numbers of KC mRNA+ cells were present in P. aeruginosa strain 6294-challenged corneas. Expression of KC mRNA was found to be up-regulated in the corneal epithelium in response to wounding alone. The KC mRNA+ cells were located in the epithelium and corresponding to infiltrating neutrophils cells in the stroma. Quantification of KC protein at different time points showed peak levels at 8 h of bacterial challenge. These results suggest that KC may be involved with the regulation of leucocyte infiltration early during bacterial keratitis.

Animals↗
PubMed2000

Pro-inflammatory cytokine/chemokine gene expression in human corneal epithelial cells colonized by Pseudomonas aeruginosa.

Pro-inflammatory cytokines interleukin-6 (IL-6), interleukin-1beta (IL- 1beta), tumour necrosis factor-alpha (TNF-alpha) and chemokine interleukin-8 (IL-8) may play a significant role in the regulation of bacterial corneal infection. The aim of this study was to investigate the gene expression of these four mediators in a human corneal epithelial cell line challenged with Pseudomonas aeruginosa within 12 h. Human corneal epithelial monolayers were colonized with P. aeruginosa strains Paerl, 6206 and 6294. Expression of IL-6, IL-8, IL-1beta and TNF-alpha was analysed using semi-quantitative reverse transcription-polymerase chain reaction. Results showed that both IL-6 and IL-8 mRNA were expressed very early (4 h) during bacterial colonization and remained at high levels until the end of the experiment. Expression of IL-1beta and TNF-alpha mRNA appeared at 8 h after bacterial stimulation. No expression of IL-8, IL-1beta and TNF-alpha mRNA was observed in unstimulated cells. Interleukin-6 mRNA was expressed at low levels in unstimulated cells. In conclusion, bacterial colonization of human corneal epithelial cells induced expression of IL-6 and IL-8 mRNA earlier and at higher levels than IL-1beta and TNF-alpha mRNA.

Cell Count↗
PubMed2000

The differential regulation of nitric oxide by Herpes simplex virus-1 and -2 in a corneal epithelial cell line.

Herpes simplex keratitis s a significant cause of blindness worldwide. Nitric oxide (NO) has been shown to play a role in non-specific defence mechanisms and cell signalling in bacterial and parasitic infections. We investigated if Herpes simplex virus (HSV) isolated from keratitis could induce NO production. Human corneal epithelial cells were infected with high (multiplicity of infection; MOI 0.4) and low (MOI 0.04) HSV-1 and HSV-2 concentrations. Culture supernatants were collected at 1 h, 4 h, 8 h, 12 h and 24 h postchallenge. Samples were prepared by removal of proteins by ultrafiltration. Production of NO was measured using nitrite and nitrate assays. Herpes simplex virus-1 downregulated the production of NO, while HSV-2 upregulated NO production. Downregulation of NO could be a survival strategy against the cytotoxic action of NO, to eliminate infected cells. Upregulation of NO production may be associated with the presence of glycoproteins on the viral coat, which have been shown to induce NO in other disease conditions. Further studies are required to confirm the role of NO in viral keratitis.

Adenoviridae↗
PubMed2000

Staphylococcus aureus causes acute inflammatory episodes in the cornea during contact lens wear.

The aim of this investigation was to determine the ability of Staphylococcus aureus to cause keratitis during contact lens wear in the rabbit. Rabbits were fitted with hydrogel lenses and wore them on an extended wear schedule for 7 weeks. At the end of each week of wear, one drop of S. aureus was added to the eyes, and the eyes were monitored using slit lamp bio-microscopy, with subsequent microbial and histological studies of the cornea. In the presence of S. aureus, keratitis occurred after 3 weeks of lens wear, a condition that was characterized by diffuse infiltration of the peripheral cornea and limbal redness. In the absence of bacteria, there was no infiltration until week 6. Contact lens wear also prolonged the retention of bacteria in the eye. Extended contact lens wear and S. aureus caused non-ulcerative keratitis in a rabbit model, and disturbances in the ability of the eye to remove bacteria.

Acute Disease↗
PubMed2000

Effect of dexamethasone on insulin-like growth factor-1 expression in a rabbit model of growth retardation.

BACKGROUND/PURPOSE: The maternal administration of steroids promotes fetal maturative effects in the gastrointestinal tract. To determine if fetal insulin-like growth factor-1 (IGF-1) expression is altered in response to maternal dexamethasone administration, this rabbit model of intrauterine growth retardation (IUGR) was utilized. METHODS: Eight pregnant rabbits received either dexamethasone (Dex 0.1 mg/kg/d intramuscular), or normal saline (Cont) on gestational days 26 and 27. Fetuses were harvested on gestational day 28 or 29 and were identified as favored (Fav) or runt (Runt): DexFav, DexRunt, ContFav, and ContRunt. Fetal weight was recorded and the serum, amniotic fluid, liver, kidney, and small intestine (SI) were collected. Reverse transcription polymerase chain reaction (RT-PCR) was used to measure IGF-1/beta-actin mRNA densitometric band ratios in all tissues. Radioimmunoassay (RIA) was used to measure IGF-1 protein levels in the serum and amniotic fluid. RESULTS: Weight was decreased in the Runt fetuses at all time-points (P < .08). The percent weight accretion from day 28 to 29, was greatest in the DexRunt fetus (P < .001), suggesting "catch-up" growth. All Dex fetuses (Fav and Runt) had increased liver and proximal, middle and distal SI IGF-1 mRNA at day 28 and elevated levels in the liver, proximal and distal SI at day 29 compared with control fetuses. The DexRunt fetuses had serum IGF-1 protein surpassing that of the DexFav fetus at day 28. CONCLUSIONS: This report provides the first description of maternal steroid administration effecting a marked increase in fetal IGF-1 mRNA expression and IGF-1 protein levels in an in vivo rabbit model of IUGR. The growth-retarded fetus appears to be particularly responsive.

Actins↗
PubMed2000

Bronchial perforation after closed-tube endotracheal suction.

Iatrogenic bronchial perforation is an uncommon complication in intubated premature infants. The authors present 2 cases of bronchial perforation caused by closed-tube endotracheal suction catheters. These presented in the first 3 days of life with pneumothorax requiring chest tube placement. Medical management was unsuccessful because of the high-volume air leak present and surgical intervention was required. A bronchial perforation of the right lower bronchus was identified in both cases and was repaired in the second case. This represents the first report in the literature of iatrogenic bronchial perforation in premature infants by closed-tube endotracheal suctioning catheters. Bronchial perforation requires early recognition and prompt repair if successful outcome is to be obtained.

Bronchi↗
PubMed2000

Effect of pH and inorganic carbon concentration on growth, glycerol production, photosynthesis and dark respiration of Dunaliella salina.

The growth of Dunaliella salina was studied with respect to pH and varying concentrations of NaHCO3 in the medium. The growth rate, photosynthesis and dark respiration were maximal at pH 8 and 4 mM NaHCO3 in the medium. Photosystem I of the Hill reaction was affected more by inorganic carbon concentration than photosystem II.

Carbon Compounds, Inorganic↗
PubMed1999

Laryngeal swabs for diagnosing tuberculosis.

The value of smear and culture of laryngeal swabs as a method of confirming pulmonary tuberculosis was investigated in Indian children. A total of 116 children with 'suspected' tuberculosis had a Mantoux test and chest X-ray. Of these, 51 had a positive Mantoux and/or chest X-ray compatible with tuberculosis, and this group had two laryngeal swabs taken on each of 3 consecutive days. The Mantoux test was positive in 37 (73%) of the 51 'probable' cases. Chest X-ray was abnormal in 36 (71%) cases and compatible with tuberculosis in 20 (39.7%). Mycobacterium tuberculosis was cultured from laryngeal swabs in 14 (28%) children and in another three children smears were positive but culture-negative. The overall confirmation rate for tuberculosis was 33%. Laryngeal swabs are a simple method of confirming tuberculosis and may be undertaken in out-patients.

Adolescent↗