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Biomedical subjects

M Khan

Publications and source records attributed to M Khan.

At least 127 records · Page 7Linked to original sources
PubMed1999

Ascaris-induced liver abscess.

The prevalence, symptomatology, and outcome of Ascaris-induced liver abscess was studied prospectively in Kashmir, India, which is an endemic area of ascariasis, from December 1987 to December 1997. Of 510 patients with liver abscess admitted during this period, 74 had biliary ascariasis as the cause (14.51%). Of these 74 patients, 11 had intact ascaridae (live or dead) within the abscess. Six patients had a single abscess, and five had multiple abscesses. Seven patients had associated worms in the bile ducts. Ultrasonography was the main diagnostic procedure used. Ten patients were diagnosed based on clinical and ultrasound findings, and one was diagnosed during laparotomy. Most of the patients were young (age range 3-40 years) with a mean age of 17.20 years. Seven were females, and four were males. Ten patients underwent surgery; nine recovered completely, and one died postoperatively due to septicemia. Another patient died as well: a young child who presented late, was in refractory septic shock following suppurative cholangitis and liver abscess, and could not be taken for surgery. The mortality thus was 9.9%. Liver abscess following invasion of intrahepatic biliary radicles by ascaridae through the ampulla is an unusual complication of an otherwise common disease in Kashmir Valley, affecting children and young adults. The outcome depends on early diagnosis and surgical drainage of the abscess with extraction of worms from the ducts.

Adolescent↗
PubMed1999

Regulation of DNA synthesis in Leydig cells obtained from neonatal pig testes.

Three distinct waves of Leydig cell development are found in the pig testes, which occur during fetal, perinatal, and prepubertal periods. Proliferation of Leydig cells is primarily regulated by luteinizing hormone (LH); however, effects of LH on proliferation of immature rat Leydig cells are mediated by specific growth factors and cytokines such as transforming growth factor-alpha (TGFalpha), insulin-like growth factor-1 (IGF-1), interleukin-1beta (IL-1beta), steroidogenesis-inducing protein (SIP), and TGFbeta. The objective of the present study was to identify growth factors that could possibly be involved in the proliferation of Leydig cells in the neonatal pig testis. Leydig cells were isolated from 3- to 5-d-old pig testes, cultured for 48 hr in serum-free media, washed, and treated with hCG and/or IGF-1, epidermal growth factor (EGF), IL-1beta, SIP, and TGFbeta for 18 hr. Tritiated thymidine incorporation into DNA was assessed over a subsequent 4-hr period. Incorporation of [3H]-thymidine was stimulated by hCG treatment with a 2.3-fold increase over control cultures. SIP also induced a significant increase (P < 0.0001) in the incorporation of [3H]thymidine into Leydig cell DNA. Similarly, EGF and IGF-1 also increased DNA synthesis in neonatal porcine Leydig cells, whereas IL-1beta had no effect. TGFbeta had very little, if any, effect on DNA synthesis when added alone, but inhibited the stimulatory effects of other mitogens (SIP, hCG, EGF/TGFalpha, and IGF-1). Our results indicate that these growth factors may play a role in the LH/hCG-dependent proliferation of Leydig cells during the perinatal period of development.

Animals↗
PubMed1999

Reversible activation of c-Myc in skin: induction of a complex neoplastic phenotype by a single oncogenic lesion.

The protooncogene c-myc regulates cell growth, differentiation, and apoptosis, and its aberrant expression is frequently observed in human cancer. However, the consequences of activating c-Myc in an adult tissue, in which these cellular processes are part of normal homeostasis, remain unknown. In order to achieve this, we have targeted expression of a switchable form of the c-Myc protein to the skin epidermis, a well characterized homeostatic tissue. We show that activation of c-MycER in adult suprabasal epidermis rapidly triggers proliferation and disrupts differentiation of postmitotic keratinocytes. Sustained activation of c-Myc is sufficient to induce papillomatosis together with angiogenesis--changes that resemble hyperplastic actinic keratosis, a commonly observed human precancerous epithelial lesion. All these premalignant changes spontaneously regress upon deactivation of c-MycER.

Animals↗
PubMed1999

Clinical significance of hepatic dysfunction with jaundice in typhoid fever.

A retrospective case note review was undertaken to assess the clinical significance of hepatic dysfunction with jaundice in typhoid fever. Of the 57 patients, 21 (36.8%) had jaundice, while 36 (63.2%) did not have jaundice. Significantly higher proportions of jaundiced patients were females (P = 0.04). Confusion (P = 0.01), upper abdominal pain (P = 0.02), right upper quadrant tenderness (P = 0.0001), and low prothrombin index (P = 0.04) were statistically significant occurrences in jaundiced patients on admission. Admission mean values of serum bilirubin (P = 0.0001), gamma-glutamyltranspeptidase (GGT; P = 0.009), and alanine aminotransferase (ALT; P = 0.0005) were significantly higher in icteric patients while mean values of total serum protein (P = 0.0009) and albumin (P = 0.0001) were significantly higher in anicteric patients. There were no deaths. Glomerulonephritis occurred significantly (P = 0.001) more frequently in icteric patients. It is concluded that hepatic dysfunction with jaundice in typhoid fever indicates more severe hepatic injury, which may precipitate the development of clinically detectable glomerulonephritis.

Adolescent↗
PubMed1999

Reference values of total serum IgE and their significance in the diagnosis of allergy among the young adult Kuwaiti population.

BACKGROUND: The reference total serum immunoglobulin (IgE) values and the usefulness of total IgE values in the diagnosis of allergy have not been established for the Kuwaiti population. The literature reference values may not be applicable since such values often vary among ethnic nationalities. OBJECTIVE: The aim of this study was to establish the reference IgE values for the young adult Kuwaiti population and to determine the usefulness of such values in the diagnosis of allergic diseases in the community. METHODS: A total of 1057 randomly selected young adults were screened for atopy using the Pharmacia CAP-PhadiatopR method. Atopy was detected in 423 individuals (40.0%). Total serum IgE was then measured in 542 randomly selected Phadiatop-negative (non-atopic) cases in the age range 18-50 years (mean 28.9 years) and male:female ratio of 1.3. RESULTS: Serum total IgE values in non-atopics covered a very wide range (< 2-1993 kU/L) with a geometric mean (GM) value of 43.7 kU/L. The reference range, calculated as the 95% confidence interval of the log IgE (95% CI) was 3.2-602.5 kU/L. The 90% CI was 11.7-162 kU/L. The GM was significantly higher for males than females, (53.7 vs. 35.5 kU/L, P < 0.001) and for smokers than non-smokers, (64.6 vs. 40.7 kU/L, P < 0.01), but was independent of age. Although the GM for the non-atopics (43.7 kU/L) was significantly lower than those of the asymptomatic atopics (213.8 kU/L) and allergic asthmatics (626.6 kU/L), the 95% CI for the three groups showed considerable overlap. CONCLUSIONS: These results show that the normal total IgE values in the young adult Kuwaiti population are generally high and that the distribution of the values is so wide that the diagnostic value of total serum IgE in this community is likely to be very limited.

Adolescent↗
PubMed1999

Atheroprotection with amlodipine: cells to lesions and the PREVENT trial. Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial.

Oxidized lipid and calcium regulatory abnormalities appear to play important roles in early atherogenesis secondary to cholesterol enrichment of the cell membrane in endothelial and arterial smooth muscle cells (SMCs). However, the link between the two is poorly understood. The findings reviewed here demonstrate that amlodipine has membrane-modifying and antioxidant actions at the cell membrane level in addition to its classical calcium channel blocking properties. These multiple pharmacologic actions may explain the cellular mechanisms of the atheroprotective effects of amlodipine in spontaneous atherogenesis and in accelerated atherosclerotic syndromes. Recent animal model studies have demonstrated that amlodipine inhibits the progression of atherosclerotic lesions and protects against restenosis after angioplasty. Amlodipine inhibits the cholesterol-induced increase in calcium permeability in SMCs, and has been shown to repair abnormalities in SMC membrane structure. Recent data have also demonstrated that amlodipine has a marked antioxidant action in membrane bilayers enriched with polyunsaturated fatty acids. However, these findings have been in animal models only; the efficacy of amlodipine in atheroprotection in humans cannot be predicted. The PREVENT trial has therefore been launched to examine the atheroprotective potential of amlodipine in spontaneous lesion development in humans with ischemic heart disease and in the prevention of restenosis after angioplasty.

Amlodipine↗
PubMed1999

A search for the evidence supporting community paediatric practice.

AIM: Controversy exists regarding the evidence base of medicine. Estimates range from 20% to 80% in various specialties, but there have been no studies in paediatrics. The aim of this study was to ascertain the evidence base for community paediatrics. METHODS: Twelve community paediatricians working in clinics and schools in Yorkshire, Manchester, Teesside, and Cheshire carried out a prospective review of consecutive clinical contacts. Evidence for diagnostic processes, prescribing, referrals, counselling/advice, and child health promotion was found by searching electronic databases. This information was critically appraised and a consensus was obtained regarding quality and whether it supported actions taken. RESULTS: Two hundred and forty-seven consultations and 1149 clinical actions were performed. Good evidence was found from a randomised controlled trial or other appropriate study for 39.9% of the 629 actions studied; convincing non-experimental evidence for 7%; inconclusive evidence for 25.4%; evidence of ineffectiveness for 0.2%; and no evidence for 27.5%. Prescribing and child health promotion activities had the highest levels of quality evidence, and counselling/advice had the lowest. CONCLUSIONS: An encouraging amount of evidence was found to support much of community paediatric practice. This study improved on previous research in other specialties because actions other than medications and surgery were included.

Child↗
PubMed1999

Exploring the scope for advocacy by paediatricians.

AIMS: To ascertain the type and extent of problems requiring advocacy in paediatrics. To develop an approach for analysing problems according to their root causes and the level of society at which advocacy is needed. METHODS: Nine paediatricians kept detailed clinical diaries for two weeks to identify problems. Classifications were developed to categorise problems by cause and the level of society at which they needed to be addressed. The press was surveyed for one week for childhood issues attracting media attention. RESULTS: 60 problems requiring advocacy were identified. Root causes included failures within agencies, between agencies, and inadequate provision. In addition to advocacy required individually, "political" action was needed at the community level (16 issues), city level (16 issues), and nationally (15 issues). 103 articles were found in the press, these did not relate closely to issues identified by clinicians. CONCLUSIONS: Many opportunities for advocacy arise in the course of daily work. A systematic way of analysing them has been developed for use in planning action. To optimise the health and health care of children, there is a need to train and support paediatricians in advocacy work for local as well as national issues. Ten issues were identified that might be prioritised by paediatricians working on an agenda for action.

Child↗
PubMed1999

Epidemic and endemic seroprevalence of antibodies to Cryptosporidium and Giardia in residents of three communities with different drinking water supplies.

This study was carried out to compare cryptosporidiosis and giardiasis seroprevalence rates in residents of three communities. Community (Com 1) uses drinking water from deep wells, community 2 (Com 2) uses surface water from a protected watershed, and community 3 (Com 3) uses surface water frequently containing Cryptosporidium oocysts and Giardia cysts. Unfiltered drinking water from each community was collected at the tap and tested for Cryptosporidium oocysts and Giardia cysts during the 12 months in which sera were collected for testing. No oocysts or cysts were detected in the water from the Com 1 deep wells; oocysts and cysts were detected intermittently in the drinking water from the other two communities. A waterborne outbreak of cryptosporidiosis occurred in a municipality adjacent to Com 3 six months into this 12-month study. Sera from residents of each of the communities were collected proportionately by month and by population size. Coded sera were tested for IgG to Cryptosporidium using a previously developed Western blotting method. The presence or absence of bands at 15-17 kD and/or 27 kD was recorded for the 1,944 sera tested. Definite bands at 15-17 kD and/or 27 kD were detected in 981 (50.5%) of the sera. A total of 33.2% of sera from Com 1 (community using deep wells) were positive using the same criteria compared with 53.5% (Com 2) and 52.5% (Com 3) of sera from the two communities using surface drinking water. Both bands (15-17 kD plus 27 kD) were detected in 582 sera (29.9%) from the three communities: 14.1% of sera from Com 1 compared with 32.7% from Com 2 and 31.5% from Com 3. These findings are consistent with a lower risk of exposure to Cryptosporidium from drinking water obtained from deep well sources. However, analysis of results by calendar quarter showed a significant (P < 0.001) increase in the number of Com 3 positive sera (compared with Com 1) following the waterborne outbreak. Without this outbreak-related observation, a significant overall difference in seropositivity would not have been seen. We also observed that in sera from the community affected by the outbreak, the presence on immunoblots of both Cryptosporidium bands appeared to be the best indicator of recent infection. Seroprevalence rates using an ELISA to detect IgG to Giardia were estimated using the same sera. Overall 30.3% (590 of 1,944) of sera were positive by the ELISA. A total of 19.1% of sera from Com 1, 34.7% from Com 2 and 16.0% from Com 3 were seropositive. Rates for both Com 3 and Com 1 did not change significantly over time. In Com 2, rates decreased significantly (P < 0.001) during the last half of the study period (third and fourth calendar quarters). The reasons for the decrease in seroprevalence in Com 2 sera are presently not known. These studies show intriguing associations between seroprevalence, outbreak-related laboratory serologic data, and patterns of parasite contamination of drinking water. Further studies are required to validate the serologic approach to risk assessment of waterborne parasitic infections at a community level.

Animals↗
PubMed1999

Influence of sex on clinical features, laboratory findings, and complications of typhoid fever.

Clinical features, laboratory findings, and complications of typhoid fever were correlated with sex through a retrospective case note review of 102 hospitalized culture-positive patients in Durban, South Africa. Intestinal perforation (P = 0.04), occult blood losses in stools (P = 0.04), and a mild reticulocytosis in the absence of hemolysis (P = 0.02) occurred more frequently in males than in females. A single pretreatment Widal O antibody titer > or = 1:640 was also a statistically significant occurrence in males (P = 0. 006). Female patients were significantly more severely ill (P = 0.0004) on admission and had chest signs consistent with bronchopneumonia (P = 0.04), transverse myelitis (P = 0.04), abnormal liver function test results (P = 0.0003), and abnormal findings in urinalyses (P = 0.02). Typhoid hepatitis (P = 0.04) and glomerulonephritis (P = 0.02) were present significantly more frequently in females. Whether these differences were due to differences in host's immune response to acute infection need to be determined in a prospective study.

Adolescent↗
PubMed1999

Hyperlipidemia and neuropathy.

Detailed histories/physical examinations (n = 47) and nerve conduction studies (n = 34) were performed in a large kindred with congenital partial lipodystrophy (CPL) in an effort to evaluate the association of hyperlipidemia and neuropathy. CPL, in the absence of diabetes, did not predispose to either focal mononeuropathy or generalized polyneuropathy, and the likelihood of either did not correlate with the degree of cholesterol or triglyceride elevation. This study does not provide support for an association between neuropathy and hyperlipidemia.

Adolescent↗
PubMed1999

Study of the mechanisms of killing of Mycobacterium bovis BCG by apoptosis in J774 murine macrophages.

OBJECTIVE: To determine the relationship between the mechanism of apoptosis and intracellular killing of Mycobacterium bovis BCG. Apoptosis, "programmed cell death"--a physiologically beneficial and distinct form of cell death. SETTING: In vitro study was carried out in murine macrophage cell line J774 that was infected with Mycobacterium bovis BCG in different set of conditions. Percentage of surviving BCG and apoptotic cells was determined. METHODS: IFN-g and/or LPS-activated and non-activated J774 mouse macrophage cells were infected with BCG in a ratio of 1:5. The morphology of the host cells was studied after 4 hours, 24 hours and 48 hours of infection in cytospins stained with Jenner-Giemsa. Surviving bacteria were counted by incorporation of radiolabelled-uridine after cell lysis. RESULTS: Both in the activated and non-activted J774 cultures some cells undergo apoptosis. In cells activated with IFN-g or LPS without BCG, less than 10% of cells were found to be apoptotic. More apoptosis was seen when LPS-activated cells were infected with BCG. In the cells activated with IFN-g or LPS-activated cells the percentage of apoptotic cells was much higher than in non-activated cells or cells activated with either INF-g or LPS alone. After 24 hours culture, without BCG, about 15% of the cells were found to be apoptotic and with BCG infection this increased to 23% (p < 0.01). The level further increased after 48 hours of infection. BCG growth inhibition was observed in both non-activated J774 cells and cells activated with LPS, INF-g or both and was sustained to 48 hours of co-culture. CONCLUSION: It is evident that BCG-infected J774 cells undergo apoptosis in the presence of a high concentration of RNI and/or ROI. During this process the cells shrink considerably in volume with the removal of water that may concentrate toxic products in the cell. The increased concentration of toxic species and the disorganisation of the phagocytic vacuoles may account for the enhanced stasis and/or death of the intracellular micro-organisms. We conclude that host cell apoptosis may arrest the growth and account for the death of the intracellular mycobacterial pathogen.

Animals↗
PubMed1998

A multidisciplinary approach for improving services in primary care: randomised controlled trial of screening for haemoglobin disorders.

OBJECTIVE: To investigate the feasibility of improving screening for carriers of haemoglobin disorders in general practice by using a nurse facilitator to work with primary care teams and the relevant haematology laboratories; to identify problems in communication between all those involved in delivering the service, and to implement solutions. DESIGN: Two year, practice based randomised controlled trial. SETTING: North London area where 29% of residents and 43% of births are in ethnic groups at risk for haemoglobin disorders. SUBJECTS: 26 of the 93 practices using the services of the area's haematology laboratory agreed to take part and were randomly divided into control and intervention practices. MAIN OUTCOME MEASURE: Change in number of requests for screening tests for haemoglobin disorders made by control and intervention practices in baseline and intervention years. RESULTS: The number of screening tests requested varied from 0-150 in the 93 practices in the baseline year. Study practices tended to have made a moderate number of requests (10-50) during this period. During the intervention year intervention practices made 292 more requests (99% increase) and control practices made 74 fewer requests (23% decrease; P=0.001 for difference in median change). Four practices, three of which were singlehanded, accounted for 75% of the increase. The number of requests from intervention practices, adjusted for baseline requests, was 3.2 times higher than control practices (P<0.0001). CONCLUSION: General practitioners and practice nurses are willing to undertake a new genetic screening service (or expand an existing one) if they are persuaded that it benefits the health of a significant proportion of their practice population. They need appropriate tools (for example, information materials for carriers and groups at risk), and the laboratory must be sensitive to their needs. Preconceptional carrier screening and counselling need to be coupled with antenatal screening.

Communication↗
PubMed1998

Cytokine-mediated induction of ceramide production is redox-sensitive. Implications to proinflammatory cytokine-mediated apoptosis in demyelinating diseases.

The present study underlines the importance of reactive oxygen species in cytokine-mediated degradation of sphingomyelin (SM) to ceramide. Treatment of rat primary astrocytes with tumor necrosis factor-alpha (TNF-alpha) or interleukin-1beta led to marked alteration in cellular redox (decrease in intracellular GSH) and rapid degradation of SM to ceramide. Interestingly, pretreatment of astrocytes with N-acetylcysteine (NAC), an antioxidant and efficient thiol source for glutathione, prevented cytokine-induced decrease in GSH and degradation of sphingomyelin to ceramide, whereas treatment of astrocytes with diamide, a thiol-depleting agent, alone caused degradation of SM to ceramide. Moreover, potent activation of SM hydrolysis and ceramide generation were observed by direct addition of an oxidant like hydrogen peroxide or a prooxidant like aminotriazole. Similar to NAC, pyrrolidinedithiocarbamate, another antioxidant, was also found to be a potent inhibitor of cytokine-induced degradation of SM to ceramide indicating that cytokine-induced hydrolysis of sphingomyelin is redox-sensitive. Besides astrocytes, NAC also blocked cytokine-mediated ceramide production in rat primary oligodendrocytes, microglia, and C6 glial cells. Inhibition of TNF-alpha- and diamide-mediated depletion of GSH, elevation of ceramide level, and DNA fragmentation (apoptosis) in primary oligodendrocytes by NAC, and observed depletion of GSH, elevation of ceramide level, and apoptosis in banked human brains from patients with neuroinflammatory diseases (e.g. X-adrenoleukodystrophy and multiple sclerosis) suggest that the intracellular level of GSH may play a critical role in the regulation of cytokine-induced generation of ceramide leading to apoptosis of brain cells in these diseases.

Acetylcysteine↗
PubMed1998

Restoration of phytanic acid oxidation in Refsum disease fibroblasts from patients with mutations in the phytanoyl-CoA hydroxylase gene.

Refsum disease (RD) is biochemically characterized by the excessive accumulation of phytanic acid in tissues and body fluids due to deficiency of phytanoyl-CoA hydroxylase (PAHX). In this study, we screened three RD patients and identified a novel deletion (88 amino acids), and a missense mutation (Arg275Trp) in the previously reported PAHX cDNA (Jansen et al., 1997; Mihalik et al., 1997). Moreover, transfection of skin fibroblasts from two RD patients with wild-type PAHX gene restored the activity for alpha-oxidation of phytanic acid. Southern analysis on a somatic cell hybrid panel detected the PAHX gene on chromosome 10, corroborating radiation hybrid and homozygosity mapping data (Mihalik et al., 1997; Nadal et al., 1995).

Chromosome Mapping↗
PubMed1998

Lovastatin and sodium phenylacetate normalize the levels of very long chain fatty acids in skin fibroblasts of X- adrenoleukodystrophy.

The present study underlines the importance of lovastatin, an inhibitor of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase, and the sodium salt of phenylacetic acid (NaPA), an inhibitor of mevalonate pyrophosphate decarboxylase, in normalizing the pathognomonic accumulation of saturated very long chain fatty acids (VLCFA) in cultured skin fibroblasts of X-adrenoleukodystrophy (X-ALD) in which the ALD gene is either mutated or deleted. Lovastatin or NaPA alone or in combination stimulated the beta-oxidation of lignoceric acid (C24:0) and normalized the elevated levels of VLCFA in skin fibroblasts of X-ALD. Ability of lovastatin and NaPA to normalize the pathognomonic accumulation of VLCFA in skin fibroblasts of X-ALD may identify these drugs as possible therapeutics for X-ALD.

Adrenoleukodystrophy↗