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Biomedical subjects

A M Khan

Publications and source records attributed to A M Khan.

At least 55 records · Page 3Linked to original sources
PubMed2000

A prospective randomized placebo-controlled double-blinded pilot study of misoprostol rectal suppositories in the prevention of acute and chronic radiation proctitis symptoms in prostate cancer patients.

OBJECTIVE: Radiation proctitis is a known complication of radiation therapy for prostate cancer. Available medical treatment is usually ineffective and has focused on relieving symptoms after damage has occurred. Our study aimed at evaluating the use of misoprostol rectal suppositories in the prevention of acute as well as chronic radiation proctitis symptoms. METHODS: A prospective, randomized, placebo-controlled, double-blinded trial was conducted in patients with recently diagnosed stages B and C prostate cancer who underwent external beam irradiation. Patients received either a misoprostol or a placebo suppository 1 h before each radiation session. Misoprostol suppositories were made from two 200-microg tablets (Cytotec, Searle Pharmaceuticals, Skokie, IL), whereas the placebo was made from cocoa butter. A 12-point radiation proctitis symptom score was obtained from each patient at 4, 8, 12, and 36 wk after radiation therapy. RESULTS: A total of 16 patients were enrolled. Seven patients received placebo, and nine patients received misoprostol. Mean radiation proctitis symptom scores in the placebo group were 4.86, 5.86, 5.71, and 3.83 at 4, 8, 12, and 36 wk, respectively. The mean scores in the misoprostol group were 0.78, 0.67, 0.33, and 0.37 at 4, 8, 12, and 36 wk, respectively. The difference between the two groups was statistically significant (p < 0.05) at 4, 8, 12, and 36 wk. CONCLUSION: Misoprostol rectal suppositories significantly reduce acute and chronic radiation proctitis symptoms in patients receiving radiation therapy for prostate cancer.

Acute Disease↗
PubMed2000

Medial displacement of grommets: an unwanted sequel of grommet insertion.

Grommet insertion is one of the commonest surgical procedures performed in the UK. We have come across three cases in which grommets have displaced medially in the middle ear after establishing a satisfactory post-insertion position. We suggest that an abnormally long myringotomy incision and improper placement of the grommet are responsible for this unwanted outcome.

Child↗
PubMed2000

Reversible granulocytopenia in association with riluzole therapy.

OBJECTIVE: To report a case of severe neutropenia developing in association with riluzole 200 mg/d. CASE SUMMARY: A 63-year-old woman with amyotrophic lateral sclerosis (ALS) presented with nausea, anorexia, and fever two weeks following inadvertent dose escalation of riluzole from 100 to 200 mg/d. Granulocytopenia was diagnosed and evaluation for a possible causative infectious process was negative; riluzole was considered a possible offender. Blood counts returned to normal with discontinuation of riluzole and administration of filgramstim. DISCUSSION: Riluzole is a glutamate release inhibitor used in the treatment of ALS, a devastating, progressive neurodegenerative disorder affecting motor neurons. A variety of adverse effects have been described with riluzole therapy, most commonly dizziness and gastrointestinal disorders. In this patient, multiple investigations failed to reveal an infectious cause or other drug-induced cause for the granulocytopenia. CONCLUSIONS: Granulocytopenia has been reported as an adverse effect of riluzole but is not a complication well known to clinicians, and there are no detailed reports published in the literature. In this patient, several lines of evidence raise the possibility of a causal relationship between riluzole and granulocytopenia.

Agranulocytosis↗
PubMed1999

Varicella zoster virus infection associated with high-dose chemotherapy and autologous stem-cell rescue.

A retrospective evaluation of 215 consecutive recipients of high-dose chemotherapy (HDC) and autologous stem cell rescue (ASCR) was conducted to ascertain the incidence, temporal course, and outcome of varicella zoster virus (VZV) infection. Herpes zoster was identified in 40 individuals at a median of 69 days following ASCR. Six of these cases occurred at a median of 33 days prior to ASCR but following the initiation of high doses of stem cell mobilization chemotherapy. Twenty-five percent of patients demonstrated cutaneous or systemic dissemination and 32.5% required medical intervention for post-herpetic neuralgia. All except two individuals received antiviral chemotherapy. One patient with active VZV infection died of multiorgan failure 39 days after ASCR. Multivariate analysis of risk factors disclosed the significance of prophylactic acyclovir use in Herpes simplex virus seropositive individuals in reducing the risk of VZV infection. Moreover, the use of busulfan, thiotepa and carboplatin as the conditioning chemotherapy regimen was associated with an increased risk of subsequent VZV infection. The incidence of VZV reactivation after HDC and ASCR is similar to that observed following bone marrow transplantation but has an earlier onset. This may be related to an earlier induction of immunosuppression by stem cell mobilization chemotherapy administered prior to ASCR. We demonstrated a marked reduction in the proliferative and synthetic capacities of peripheral blood mononuclear cells obtained prior to and following stem cell mobilizing chemotherapy. Moreover, greater than 80% of VZV infections occurred within 6 months following ASCR and late cases were seldom observed compared to allogeneic and autologous bone marrow transplantation. The role of antiviral chemoprophylaxis during the period of maximum immunocompromise needs to be studied further in the HDC-ASCR setting.

Adult↗
PubMed1999

Incidence and outcome of Clostridium difficile infection following autologous peripheral blood stem cell transplantation.

A retrospective evaluation of 200 consecutive recipients of autologous peripheral blood stem cell transplantation (PBSCT) was conducted to ascertain the incidence and outcome of infection with Clostridium difficile. The diagnosis was confirmed in 14 patients with diarrhea (15 episodes) at a median of 33 days after stem cell infusion. Five patients were neutropenic at the time of diagnosis. Every individual had adverse known risk factors such as recent or current use of antibiotic, corticosteroid and antiviral therapy, recent administration of myeloablative chemotherapy and numerous, prolonged periods of hospitalization. Diarrhea, frequently hemorrhagic, was the most common presenting feature along with fever, abdominal cramps and abdominal distention. Diagnosis was established by the stool-cytotoxin test. Response to standard treatment with oral vancomycin or metronidazole was prompt despite the presence of several adverse prognostic features in these patients. There was only one instance of relapse which was also treated successfully. Several transplant-related variables such as age, sex, underlying malignancy, myelo-ablative regimen, duration of neutropenia, and prophylactic use of oral ampicillin underwent statistical analysis but failed to be predictive of C. difficile infection in such a setting. Finally, C. difficile is not uncommon after autologous PBSCT and must be included in the differential diagnosis in any such patient with diarrhea.

Adolescent↗
PubMed1999

Lateral hypothalamic NMDA receptor subunits NR2A and/or NR2B mediate eating: immunochemical/behavioral evidence.

Cells within the lateral hypothalamic area (LHA) are important in eating control. Glutamate or its analogs, kainic acid (KA) and N-methyl-D-aspartate (NMDA), elicit intense eating when microinjected there, and, conversely, LHA-administered NMDA receptor antagonists suppress deprivation- and NMDA-elicited eating. The subunit composition of LHA NMDA receptors (NMDA-Rs) mediating feeding, however, has not yet been determined. Identifying this is important, because distinct second messengers/modulators may be activated by NMDA-Rs with differing compositions. To begin to address this, we detected LHA NR2A and NR2B subunits by immunoblotting and NR2B subunits by immunohistochemistry using subunit-specific antibodies. To help determine whether NMDA-Rs mediating feeding might contain these subunits, we conducted behavioral studies using LHA-administered ifenprodil, an antagonist selective for NR2A- and/or NR2B-containing NMDA-Rs at the doses we used (0.001-100 nmol). Ifenprodil maximally suppressed NMDA- and deprivation-elicited feeding by 63 and 39%, respectively, but failed to suppress KA-elicited eating, suggesting its actions were behaviorally specific. Collectively, these results suggest that LHA NMDA-Rs, some of which contribute to feeding control, are composed of NR2A and/or NR2B subunits, and implicate NR2A- and/or NR2B-linked signal transduction in feeding behavior.

Animals↗
PubMed1999

Effects of dexamethasone on meconium aspiration syndrome in newborn piglets.

We examined the effects of dexamethasone on lung function in a piglet model of meconium aspiration syndrome. We induced lung injury in 10 newborn piglets (age 5 +/- 0.2 d) with 4 mL/kg body weight of 20% sterile human meconium in normal saline given via tracheostomy. Ventilator management was aimed at maintaining comparable values of end tidal carbon dioxide, Hb saturation, and arterial blood gases. Lung function was assessed using a BICORE CP100 neonatal monitor. Five piglets received 0.5 mg/kg of dexamethasone 2 and 8 h after meconium administration, whereas control piglets received normal saline at similar times. Ventilator settings, oxygen requirements, and lung compliance were similar between groups at the start of the study. Two hours after the instillation of meconium, there was marked lung dysfunction in both groups as evidenced by increased oxygen requirements [fraction of inspired oxygen (FiO2) 0.98 +/- 0.01 versus FiO2 0.21 +/- 0, p < 0.0001] and reduced lung compliance (0.35 +/- 0.03 versus 0.8 +/- 0.03 mL x kg(-1) x cm(-1) H2O, p < 0.0001). Administration of dexamethasone resulted in lower oxygen requirements (FiO2 0.27 +/- 0.01 versus FiO2 1.0 +/- 0.0, p < 0.00001), lower oxygenation index (2.17 +/- 0.17 versus 22.64 +/- 3.39, p < 0.0001), ventilatory efficiency index (0.30 +/- 0.01 versus 0.07 +/- 0.01, p < 0.0001), and improved lung compliance (0.68 +/- 0.04 versus 0.34 +/- 0.05 mL x kg(-1) x cm(-1) H2O, p < 0.001) compared with the control group. In summary, a two-dose course of 0.5 mg/kg of dexamethasone improved blood gases and lung function in a piglet model of meconium aspiration syndrome.

Animals↗
PubMed1999

Use of a custom retrograde intramedullary rod for the management of distal femoral nonunion: a report of two cases.

Nonunion of the distal femur is a rare injury that is difficult to manage. A variety of surgical implants and techniques are available. We present an alternative mode of treatment for supracondylar femoral nonunion using a custom retrograde titanium femoral nail (Biomet; Warsaw, IN) to successfully achieve union in two cases. We believe the added length, custom modifications, and enhanced stability allowed better fixation in an osteopenic distal femur.

Adult↗
PubMed1999

Lymphatic filariasis in two distinct communities of upper Assam.

Current status of bancroftian filariasis among two distinct communities of Upper Assam was evaluated. High prevalence (10.3% mf rate) in tea workers descendents of tribals migrated from endemic states such as Orissa, Bengal, Uttar Pradesh and southern states of India, were recorded. Among non tea workers (indigenous population) significantly low mf rate was found in spite of the fact that both the communities are living in close vicinity and in similar ecological and mosquitogenic conditions. Culex quinquefasciatus was incriminated as vector in the areas of both the communities. A group of recent migrants of Bihar and Bengal living in the locality of non tea worker population were also found microfilaraemic. Significantly lower infection rate in non tea worker population appears to be associated with host susceptibility to the infection. Familial clustering in microfilaraemic subjects noticed in tea workers group also suggests involvement of racial susceptibility to infection.

Adolescent↗
PubMed1998

The second messenger cAMP elicits eating by an anatomically specific action in the perifornical hypothalamus.

We have previously shown that a membrane-permeant analog of cAMP, 8-bromo-cAMP (8-br-cAMP), elicits a vigorous eating response when microinjected into the perifornical hypothalamus (PFH) or lateral hypothalamus (LH) of satiated rats, suggesting that increases in cAMP in these areas may be important in the neural control of eating. To determine the locus of this effect, we compared the ability of 8-br-cAMP (1-100 nmol/0.3 microl) to elicit eating after microinjection into the PFH, LH, or the following bracketing areas: the anterior and posterior LH, paraventricular nucleus of the hypothalamus, thalamus, and amygdala. 8-br-cAMP at 50 nmol elicited eating (>/=3.4 gm in 2 hr) exclusively in the PFH and LH. At 100 nmol, 8-br-cAMP elicited a larger response in these areas and elicited a smaller, more variable response in the thalamus. We similarly mapped the feeding-stimulatory effects of compounds that increase endogenous cellular cAMP in naive rats. Combined microinjection of matched doses (300 nmol) of 3-isobutyl-1-methylxanthine and 7-deacetyl-7-O-(N-methylpiperazino)-gamma-butyryl-forskolin was effective exclusively in the PFH, eliciting an average 2 hr food intake of 8.4 +/- 2.0 gm. Collectively, these results suggest that increases in cellular cAMP within a specific brain site, the PFH, may play a role in the neural stimulation of eating.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Colocalization of calretinin and calbindin-D28k with oxytocin and vasopressin in rat supraoptic nucleus neurons: a quantitative study.

Recent electrophysiological experiments, in which purified calbindin-D28k (calbindin) and calretinin antibodies were diffused into these neurons, showed that Ca2+-dependent membrane potentials and firing patterns were profoundly and predictably affected by Ca2+-binding proteins (CaBPs). The present study used quantitative analyses of a dual-labeling immunofluorescence method to investigate the colocalization of the CaBPs, calbindin and calretinin in oxytocin (OT)- and (VP)-containing neurons of the supraoptic nucleus. Analyses of tissue immunostained with two different dilutions of each CaBP antibody used, revealed that 84% and 72% of the OT neurons were positive for calbindin immunoreactivity (-ir) at the higher and lower antibody concentrations, respectively. 52% and 50% of OT neurons were positive for calretinin-ir; thus, many OT neurons express both calbindin and calretinin. In contrast, only 25% and 18% of VP neurons showed calbindin-ir, and they were virtually devoid of calretinin-ir. These results provide evidence that CaBP expression in OT neurons is both greater and more diverse than in VP neurons, and are consistent with the hypothesis that Ca2+ buffering capacity contributes to the control of intrinsic firing patterns.

Analysis of Variance↗
PubMed1998

Utility of daily head ultrasonography for infants on extracorporeal membrane oxygenation.

BACKGROUND/PURPOSE: Intracranial hemorrhage (ICH) is a major concern during extracorporeal membrane oxygenation (ECMO). Daily cranial ultrasonography has been used by many ECMO centers as a diagnostic tool for both detecting and following ICH while infants are on bypass. The purpose of this patient review was to look at the usefulness of performing daily cranial ultrasonography (HUS) in infants on ECMO in detecting intraventricular hemorrhage of a magnitude sufficient to alter patient treatment. METHODS: The authors reviewed retrospectively all of the records of all neonates treated with ECMO at the Hermann Children's Hospital, Wilford Hall USAF Medical Center, Cincinnati Children's Hospital, The University of Texas Medical Branch at Galveston, and Texas Children's Hospital between February 1986 to March 1995. Two hundred ninety-eight patients were placed on ECMO during this period. All patients had HUS before, and daily while on ECMO, and all were reviewed by the staff radiologists. A total of 2,518 HUS examinations were performed. RESULTS: Fifty-two of 298 patients (17.5%) had an intraventricular hemorrhage seen on ultrasound scan. Nine of 52 patients (17.3%) had an ICH seen on the initial HUS examination before ECMO, all of which were grade I, and 43 of 52 patients (82.7%) had ICH while on ECMO. Of these ICH, 15 were grade I, 10 were grade II, 10 were grade III, and eight were grade IV. Forty of these ICH (93%) were diagnosed by HUS during the first 5 days of the ECMO course. Seven hundred eighty-six HUS were performed after day 5, at an estimated cost of $300,000 to $450,000 (charges), demonstrating three new intraventricular hemorrhages, one grade I, and one grade IV on day 7 and one grade I on day 8. Eight patients were taken off ECMO because of ICH diagnosed within the first 5 days. One patient was taken off ECMO because of ICH diagnosed after 5 days. This patient had clinical symptoms suggestive of ICH. CONCLUSIONS: Almost all ICH occur during the first 5 days of an ECMO course. Unless there is a clinical suspicion, it is not cost effective to perform HUS after the fifth day on ECMO, because subsequent HUS examinations are unlikely to yield information significant enough to alter management.

Cerebral Hemorrhage↗
PubMed1998

Effects of hyperventilation and hypoventilation on PaCO2 and intracranial pressure during acute elevations of intraabdominal pressure with CO2 pneumoperitoneum: large animal observations.

BACKGROUND: The side effects of acute elevations in intraabdominal pressure (IAP) are related to a multifactorial etiology. Previous studies have reported that acute elevations in IAP produce an immediate increase in intracranial pressure (ICP). This study was designed to analyze the reasons for increased ICP during acute elevations of IAP and to determine the combined effects of IAP and changes in ventilation indices on ICP and hemodynamic indices. STUDY DESIGN: Five pigs were studied. A subarachnoid screw was placed for ICP monitoring. The jugular vein, femoral vein, and femoral artery were cannulated. Mean arterial pressure (MAP), central venous pressure (CVP), ICP, and arterial pressure of carbon dioxide (PaCO2) were monitored before and after carbon dioxide pneumoperitoneum was established at 0, 10, and 20 mmHg of IAP Effects of hyperventilation and hypoventilation were recorded and compared with baseline ventilation. Cavography was performed to evaluate the morphology of the inferior vena cava (IVC) at different levels of IAP. Multiple regression and Student's t-test were used to examine the effects of IAP and ventilation on dependent variables. RESULTS: The IVC showed a progressive narrowing at the level of the diaphragm as IAP was increased. There was a simultaneous increase in CVP, MAP, and ICP. The mean changes in ICP with hypoventilation were significantly larger than with hyperventilation. CONCLUSIONS: Acutely increased IAP displaces the diaphragm cranially, narrowing the IVC and increasing intrathoracic pressure. This increases CVP and increases ICP by venous stasis and increased pressure in the sagittal sinus with decreased resorption of cerebrospinal fluid. Hemodynamic changes are directly related to the rise in ICP. Hypoventilation and hypercarbia significantly increase ICP when compared with hyperventilation and hypocarbia. Hyperventilation does not significantly decrease ICP during acute elevations of IAP.

Abdomen↗
PubMed1998

Geriatric nurse practitioners in long-term care: demonstration of effectiveness in managed care.

OBJECTIVE: This study was undertaken to review the impact of utilizing geriatric nurse practitioner/physician (GNP/ MD) teams on cost and utilization for a cohort of Medicare HMO enrollees residing in long-term care facilities. The results would be used by the organization for further development of the GNP Program. DESIGN: A 1-year retrospective data analysis on revenues and cost for 1077 HMO enrollees residing in 45 long term-care facilities. SETTING: Proprietary and not-for-profit, licensed long term care facilities in the HMO's service area of central Massachusetts. Facilities in the study had both skilled (Medicare-certified) and custodial beds. MEASUREMENTS: Data were collected retrospectively on overall cost, revenues, emergency department (ED) transfers, hospital, and subacute days. RESULTS: Of 1077 residents, 414 were cared for by GNP/MD teams compared with 663 by physicians alone. Acute care and ED costs were significantly lower for the GNP/MD-covered patients. There was a gain of $72 per resident per month (PRPM) with the GNP/MD-covered patients compared with a loss of $197 PRPM for physicians alone. There were no significant differences in ancillary services or prescriptions. CONCLUSION: The use of GNPs in collaboration with physicians reduced ED and acute care utilization costs as well as overall costs for a cohort of HMO enrollees in long-term care. This encouraged the HMO to support the concept that all long-term care HMO residents should be covered by GNP/MD teams.

Aged↗